{ "name": "ChatPPG Wearable Accuracy Database", "version": "1.0.0", "released": "2026-10-17", "license": "CC BY 4.0", "description": "Published validation results for consumer wearables, one row per device × metric × statistic, each with the DOI, reference standard, sample and the exact quote it was taken from.", "citation": "ChatPPG (2026). Wearable Accuracy Database, version 1.0.0. https://chatppg.com/research/accuracy", "method": [ "Original papers only, taken from the abstract or open full text; every DOI verified on Crossref. Preprints are marked peer_reviewed = false and never ranked.", "Each value is quoted verbatim from the source; quotes are machine-checked against the source text.", "Rankings compare rows only with the same metric, the same statistic and a comparable reference standard.", "industry_funded is true when the paper discloses funding, employment or support from the maker of that device." ], "metrics": { "hr_rest": "Heart rate at rest", "hr_exercise": "Heart rate during exercise", "hr_sleep": "Overnight heart rate", "hrv_rmssd": "HRV (RMSSD)", "spo2": "Blood oxygen (SpO2)", "sleep_stages": "Sleep stages (4-stage)", "sleep_wake": "Sleep vs wake (2-stage)", "sleep_tst": "Total sleep time", "af": "Atrial fibrillation detection", "bp": "Blood pressure", "skin_temp": "Skin temperature", "resp_rate": "Respiratory rate", "energy": "Energy expenditure (calories)", "vo2max": "VO2max estimate" }, "statistics": { "mae_bpm": { "label": "Mean absolute error", "unit": "bpm", "higher_is_better": false }, "mae_ms": { "label": "Mean absolute error (absolute bias)", "unit": "ms", "higher_is_better": false }, "mae_pct": { "label": "Mean absolute error", "unit": "% points", "higher_is_better": false }, "mae_min": { "label": "Mean absolute error", "unit": "min", "higher_is_better": false }, "mae_mlkgmin": { "label": "Mean absolute error", "unit": "mL/kg/min", "higher_is_better": false }, "mape_pct": { "label": "Mean absolute percentage error", "unit": "%", "higher_is_better": false }, "rmse_pct": { "label": "Root-mean-square error", "unit": "% points", "higher_is_better": false }, "rmse_bpm": { "label": "Root-mean-square error", "unit": "breaths/min", "higher_is_better": false }, "ccc": { "label": "Lin's concordance correlation", "unit": null, "higher_is_better": true }, "icc": { "label": "Intraclass correlation", "unit": null, "higher_is_better": true }, "r": { "label": "Pearson correlation", "unit": null, "higher_is_better": true }, "kappa": { "label": "Cohen's kappa", "unit": null, "higher_is_better": true }, "agreement_pct": { "label": "Epoch-by-epoch agreement", "unit": "%", "higher_is_better": true }, "sensitivity_pct": { "label": "Sensitivity", "unit": "%", "higher_is_better": null }, "specificity_pct": { "label": "Specificity", "unit": "%", "higher_is_better": null }, "ppv_pct": { "label": "Positive predictive value", "unit": "%", "higher_is_better": null }, "bias": { "label": "Mean bias (signed)", "unit": null, "higher_is_better": null }, "cv_pct": { "label": "Coefficient of variation", "unit": "%", "higher_is_better": false }, "finding": { "label": "Study finding (no single number)", "unit": null, "higher_is_better": null } }, "references": { "psg": "Polysomnography (PSG)", "ecg": "ECG", "ecg_chest": "ECG chest strap (Zephyr BioHarness / Faros)", "ecg_holter": "Holter ECG", "ecg_12lead": "12-lead ECG", "ecg_patch": "ECG patch", "chest_strap": "ECG chest strap (Polar H7/H10)", "chest_strap_kubios": "Polar H10 + Kubios HRV", "pulse_oximeter": "Medical-grade pulse oximeter", "arterial_blood_gas": "Arterial blood gas (SaO2)", "psg_oximetry": "PSG pulse oximetry", "indirect_calorimetry": "Indirect calorimetry", "actigraphy": "Research actigraphy", "actiheart": "Actiheart (ECG + accelerometer)", "actiheart_actigraph": "Actiheart / ActiGraph", "insertable_cardiac_monitor": "Insertable cardiac monitor", "cuff_oscillometric": "Validated cuff (Omron M4)", "abpm": "24-h ambulatory BP monitor", "cuff_calibration": "Cuff used for calibration", "oral_thermometer": "Oral thermometer" }, "studies": [ { "id": "dhawale2026", "citation": "Dhawale et al. (2026)", "title": "Accuracy of a Smart-Ring VO2max Estimate and Five Published Prediction Equations Against Cardiopulmonary Exercise Testing: Development and Validation Study With Population-Scale Analysis", "journal": "medRxiv (preprint)", "year": 2026, "doi": "10.64898/2026.07.16.26358226", "pmid": null, "url": "https://doi.org/10.64898/2026.07.16.26358226", "peer_reviewed": false, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "ultrahuman" ], "funding_note": "Corresponding author affiliation: Ultrahuman Healthcare Pvt Ltd (medRxiv record); model coefficients proprietary" }, { "id": "engel2026", "citation": "Engel et al. (2026)", "title": "Validity of V̇O2max estimates from the forerunner 245 smartwatch in highly vs. moderately trained endurance athletes", "journal": "European Journal of Applied Physiology", "year": 2026, "doi": "10.1007/s00421-025-05923-x", "pmid": "40770433", "url": "https://doi.org/10.1007/s00421-025-05923-x", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "ferreira2026", "citation": "Ferreira et al. (2026)", "title": "Validity of Galaxy Watch for Estimating Energy Expenditure During Intermittent Running: Cross-Sectional Study", "journal": "JMIR Formative Research", "year": 2026, "doi": "10.2196/83090", "pmid": "41849635", "url": "https://doi.org/10.2196/83090", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "gielen2026", "citation": "Gielen et al. (2026)", "title": "Accuracy of Optical Heart Rate Measurements for 10 Commercial Wearables in Different Climate Conditions and Activities: Instrument Validation Study", "journal": "JMIR Formative Research", "year": 2026, "doi": "10.2196/85186", "pmid": "41701929", "url": "https://doi.org/10.2196/85186", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "inoue2026", "citation": "Inoue et al. (2026)", "title": "Heart Rate Estimation Using the Galaxy Watch During Maximal Cardiopulmonary Exercise Testing: Cross-Sectional Validation Study", "journal": "JMIR Cardio", "year": 2026, "doi": "10.2196/81917", "pmid": "41990212", "url": "https://doi.org/10.2196/81917", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "jeong2026", "citation": "Jeong et al. (2026)", "title": "Comparison of heart rate measurement accuracy among commercially available photoplethysmography-based wearable devices across exercise intensities", "journal": "Physical Activity and Nutrition", "year": 2026, "doi": "10.20463/pan.2026.0032", "pmid": "42438855", "url": "https://doi.org/10.20463/pan.2026.0032", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "jiang2026", "citation": "Jiang et al. (2026)", "title": "Performance of Wearable Pulse Oximetry During Controlled Hypoxia Induction: Instrument Validation Study", "journal": "JMIR Formative Research", "year": 2026, "doi": "10.2196/85253", "pmid": "41894520", "url": "https://doi.org/10.2196/85253", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "kim2026", "citation": "Kim et al. (2026)", "title": "Evaluation of the accuracy of wrist skin temperature measured using an infrared sensor for prediction ovulation date", "journal": "Biosensors and Bioelectronics", "year": 2026, "doi": "10.1016/j.bios.2026.118755", "pmid": "42143892", "url": "https://doi.org/10.1016/j.bios.2026.118755", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "samsung" ], "funding_note": "Author affiliations include Samsung; competing interests declared" }, { "id": "kostrna2026", "citation": "Kostrna et al. (2026)", "title": "Body fat, skin tone, and the accuracy of smartwatch caloric expenditure estimates", "journal": "PLOS One", "year": 2026, "doi": "10.1371/journal.pone.0353261", "pmid": "42525581", "url": "https://doi.org/10.1371/journal.pone.0353261", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "lambe2026", "citation": "Lambe et al. (2026)", "title": "Accuracy of VO2 max Estimates From Apple Watch Series 10", "journal": "Mayo Clinic Proceedings: Digital Health", "year": 2026, "doi": "10.1016/j.mcpdig.2026.100357", "pmid": "42094313", "url": "https://doi.org/10.1016/j.mcpdig.2026.100357", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "lambe2026b", "citation": "Lambe et al. (2026)", "title": "The accuracy of VO2 max, heart rate and energy expenditure measurements from Google Pixel Watch 3", "journal": "PLOS One", "year": 2026, "doi": "10.1371/journal.pone.0356808", "pmid": "42743109", "url": "https://doi.org/10.1371/journal.pone.0356808", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "google" ], "funding_note": "COI: \"The authors received funding for this work from Google LLC\"" }, { "id": "lee2026", "citation": "Lee et al. (2026)", "title": "Comparative Validity of Smartwatch-Derived Heart Rate and Energy Expenditure During Endurance and Resistance Exercise", "journal": "Sensors", "year": 2026, "doi": "10.3390/s26082526", "pmid": "42076635", "url": "https://doi.org/10.3390/s26082526", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "mulholland2026", "citation": "Mulholland et al. (2026)", "title": "Influence of skin pigmentation on the accuracy and data quality of photoplethysmographic heart rate measurement during exercise", "journal": "European Journal of Applied Physiology", "year": 2026, "doi": "10.1007/s00421-025-05977-x", "pmid": "40968160", "url": "https://doi.org/10.1007/s00421-025-05977-x", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "searles2026", "citation": "Searles et al. (2026)", "title": "Performance evaluation of consumer sleep-tracking wearables and nearables in healthy young and older adults", "journal": "SLEEP Advances", "year": 2026, "doi": "10.1093/sleepadvances/zpag006", "pmid": "41768372", "url": "https://doi.org/10.1093/sleepadvances/zpag006", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "walzel2026", "citation": "Walzel et al. (2026)", "title": "Long-term accuracy and stability of blood pressure measurements from a smartwatch: Prospective validation study", "journal": "DIGITAL HEALTH", "year": 2026, "doi": "10.1177/20552076261415923", "pmid": "41602947", "url": "https://doi.org/10.1177/20552076261415923", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "bonneval2025", "citation": "Bonneval et al. (2025)", "title": "Validity of Heart Rate Variability Measured with Apple Watch Series 6 Compared to Laboratory Measures", "journal": "Sensors", "year": 2025, "doi": "10.3390/s25082380", "pmid": "40285070", "url": "https://doi.org/10.3390/s25082380", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "browne2025", "citation": "Browne et al. (2025)", "title": "Evaluation of Pulse Oximetry Accuracy in a Commercial Smartphone and Smartwatch Device During Human Hypoxia Laboratory Testing", "journal": "Sensors", "year": 2025, "doi": "10.3390/s25051286", "pmid": "40096012", "url": "https://doi.org/10.3390/s25051286", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "carrier2025", "citation": "Carrier et al. (2025)", "title": "Validation of Aerobic Capacity (VO2max) and Pulse Oximetry in Wearable Technology", "journal": "Sensors", "year": 2025, "doi": "10.3390/s25010275", "pmid": "39797066", "url": "https://doi.org/10.3390/s25010275", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "dial2025", "citation": "Dial et al. (2025)", "title": "Validation of nocturnal resting heart rate and heart rate variability in consumer wearables", "journal": "Physiological Reports", "year": 2025, "doi": "10.14814/phy2.70527", "pmid": "40834291", "url": "https://doi.org/10.14814/phy2.70527", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "herberger2025", "citation": "Herberger et al. (2025)", "title": "Performance of wearable finger ring trackers for diagnostic sleep measurement in the clinical context", "journal": "Scientific Reports", "year": 2025, "doi": "10.1038/s41598-025-93774-z", "pmid": "40108409", "url": "https://doi.org/10.1038/s41598-025-93774-z", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "lambe2025", "citation": "Lambe et al. (2025)", "title": "Investigating the accuracy of Apple Watch VO2 max measurements: A validation study", "journal": "PLOS One", "year": 2025, "doi": "10.1371/journal.pone.0323741", "pmid": "40373042", "url": "https://doi.org/10.1371/journal.pone.0323741", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "mendt2025", "citation": "Mendt et al. (2025)", "title": "Laboratory comparison of consumer-grade and research-established wearables for monitoring heart rate, body temperature, and physical acitivity in sub-Saharan Africa", "journal": "Frontiers in Physiology", "year": 2025, "doi": "10.3389/fphys.2025.1491401", "pmid": "40017799", "url": "https://doi.org/10.3389/fphys.2025.1491401", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "moghaddam2025", "citation": "Moghaddam et al. (2025)", "title": "Impact of Anatomical Placement on the Accuracy of Wearable Heart Rate Monitors During Rest and Various Exercise Intensities", "journal": "Sensors", "year": 2025, "doi": "10.3390/s26010176", "pmid": "41516615", "url": "https://doi.org/10.3390/s26010176", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "schyvens2025", "citation": "Schyvens et al. (2025)", "title": "A performance validation of six commercial wrist-worn wearable sleep-tracking devices for sleep stage scoring compared to polysomnography", "journal": "Sleep Advances", "year": 2025, "doi": "10.1093/sleepadvances/zpaf021", "pmid": "40303381", "url": "https://doi.org/10.1093/sleepadvances/zpaf021", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "arslan2024", "citation": "Arslan et al. (2024)", "title": "Accuracy of the Apple Watch in measuring oxygen saturation: comparison with pulse oximetry and ABG", "journal": "Irish Journal of Medical Science (1971 -)", "year": 2024, "doi": "10.1007/s11845-023-03456-w", "pmid": "37440093", "url": "https://doi.org/10.1007/s11845-023-03456-w", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "browne2024", "citation": "Browne et al. (2024)", "title": "Performance of a commercial smart watch compared to polysomnography reference for overnight continuous oximetry measurement and sleep apnea evaluation", "journal": "Journal of Clinical Sleep Medicine", "year": 2024, "doi": "10.5664/jcsm.11178", "pmid": "38652502", "url": "https://doi.org/10.5664/jcsm.11178", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "samsung" ], "funding_note": "Funding: Samsung Electronics Research Grant 30119640 (with NIH)" }, { "id": "caserman2024", "citation": "Caserman et al. (2024)", "title": "Assessing the Accuracy of Smartwatch-Based Estimation of Maximum Oxygen Uptake Using the Apple Watch Series 7: Validation Study", "journal": "JMIR Biomedical Engineering", "year": 2024, "doi": "10.2196/59459", "pmid": "39083800", "url": "https://doi.org/10.2196/59459", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "chase2024", "citation": "Chase et al. (2024)", "title": "Accuracy of the Apple Watch Series 9 for Measures of Energy Expenditure and Heart Rate at Rest and During Exercise: Impact of Skin Pigmentation", "journal": "Journal of Functional Morphology and Kinesiology", "year": 2024, "doi": "10.3390/jfmk9040275", "pmid": "39728259", "url": "https://doi.org/10.3390/jfmk9040275", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "hermans2024", "citation": "Hermans et al. (2024)", "title": "Validity of a Consumer-Based Wearable to Measure Clinical Parameters in Patients With Chronic Obstructive Pulmonary Disease and Healthy Controls: Observational Study", "journal": "JMIR mHealth and uHealth", "year": 2024, "doi": "10.2196/56027", "pmid": "39504450", "url": "https://doi.org/10.2196/56027", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "ibrahim2024", "citation": "Ibrahim et al. (2024)", "title": "Evaluation of Wrist-Worn Photoplethysmography Trackers with an Electrocardiogram in Patients with Ischemic Heart Disease: A Validation Study", "journal": "Cardiovascular Engineering and Technology", "year": 2024, "doi": "10.1007/s13239-023-00693-z", "pmid": "37973701", "url": "https://doi.org/10.1007/s13239-023-00693-z", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "ogrady2024", "citation": "O'Grady et al. (2024)", "title": "The Validity of Apple Watch Series 9 and Ultra 2 for Serial Measurements of Heart Rate Variability and Resting Heart Rate", "journal": "Sensors", "year": 2024, "doi": "10.3390/s24196220", "pmid": "39409260", "url": "https://doi.org/10.3390/s24196220", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "rajakariar2024", "citation": "Rajakariar et al. (2024)", "title": "Accuracy of Smartwatch Pulse Oximetry Measurements in Hospitalized Patients With Coronavirus Disease 2019", "journal": "Mayo Clinic Proceedings: Digital Health", "year": 2024, "doi": "10.1016/j.mcpdig.2024.02.001", "pmid": "40206673", "url": "https://doi.org/10.1016/j.mcpdig.2024.02.001", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "robbins2024", "citation": "Robbins et al. (2024)", "title": "Accuracy of Three Commercial Wearable Devices for Sleep Tracking in Healthy Adults", "journal": "Sensors", "year": 2024, "doi": "10.3390/s24206532", "pmid": "39460013", "url": "https://doi.org/10.3390/s24206532", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "oura" ], "funding_note": "COI: first author on the Oura Ring Medical Advisory Board; grant from Oura Ring Inc" }, { "id": "svensson2024", "citation": "Svensson et al. (2024)", "title": "Validity and reliability of the Oura Ring Generation 3 (Gen3) with Oura sleep staging algorithm 2.0 (OSSA 2.0) when compared to multi-night ambulatory polysomnography: A validation study of 96 participants and 421,045 epochs", "journal": "Sleep Medicine", "year": 2024, "doi": "10.1016/j.sleep.2024.01.020", "pmid": "38382312", "url": "https://doi.org/10.1016/j.sleep.2024.01.020", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "oura" ], "funding_note": "COI: authors report financial support provided by Oura Health Oy" }, { "id": "hajjboutros2023", "citation": "Hajj-Boutros et al. (2023)", "title": "Wrist-worn devices for the measurement of heart rate and energy expenditure: A validation study for the Apple Watch 6, Polar Vantage V and Fitbit Sense", "journal": "European Journal of Sport Science", "year": 2023, "doi": "10.1080/17461391.2021.2023656", "pmid": "34957939", "url": "https://doi.org/10.1080/17461391.2021.2023656", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "han2023", "citation": "Han et al. (2023)", "title": "Feasibility and measurement stability of smartwatch-based cuffless blood pressure monitoring: A real-world prospective observational study", "journal": "Hypertension Research", "year": 2023, "doi": "10.1038/s41440-023-01215-z", "pmid": "36781979", "url": "https://doi.org/10.1038/s41440-023-01215-z", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "jiang2023", "citation": "Jiang et al. (2023)", "title": "Investigating the accuracy of blood oxygen saturation measurements in common consumer smartwatches", "journal": "PLOS Digital Health", "year": 2023, "doi": "10.1371/journal.pdig.0000296", "pmid": "37437005", "url": "https://doi.org/10.1371/journal.pdig.0000296", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "jung2023", "citation": "Jung et al. (2023)", "title": "Validating a Consumer Smartwatch for Nocturnal Respiratory Rate Measurements in Sleep Monitoring", "journal": "Sensors", "year": 2023, "doi": "10.3390/s23187976", "pmid": "37766031", "url": "https://doi.org/10.3390/s23187976", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "samsung" ], "funding_note": "COI: authors affiliated with Samsung Electronics, which funded the study" }, { "id": "kristiansson2023", "citation": "Kristiansson et al. (2023)", "title": "Validation of Oura ring energy expenditure and steps in laboratory and free-living", "journal": "BMC Medical Research Methodology", "year": 2023, "doi": "10.1186/s12874-023-01868-x", "pmid": "36829120", "url": "https://doi.org/10.1186/s12874-023-01868-x", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "lee2023", "citation": "Lee et al. (2023)", "title": "Accuracy of 11 Wearable, Nearable, and Airable Consumer Sleep Trackers: Prospective Multicenter Validation Study", "journal": "JMIR mHealth and uHealth", "year": 2023, "doi": "10.2196/50983", "pmid": "37917155", "url": "https://doi.org/10.2196/50983", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "COI: some authors hold stock in Asleep (maker of the SleepRoutine app, not of any wearable listed here)" }, { "id": "mannhart2023", "citation": "Mannhart et al. (2023)", "title": "Clinical Validation of 5 Direct-to-Consumer Wearable Smart Devices to Detect Atrial Fibrillation: BASEL Wearable Study", "journal": "JACC: Clinical Electrophysiology", "year": 2023, "doi": "10.1016/j.jacep.2022.09.011", "pmid": "36858690", "url": "https://doi.org/10.1016/j.jacep.2022.09.011", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "patz2023", "citation": "Pätz et al. (2023)", "title": "Accuracy of the Apple Watch Oxygen Saturation Measurement in Adults and Children with Congenital Heart Disease", "journal": "Pediatric Cardiology", "year": 2023, "doi": "10.1007/s00246-022-02987-w", "pmid": "35995951", "url": "https://doi.org/10.1007/s00246-022-02987-w", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "selder2023", "citation": "Selder et al. (2023)", "title": "Accuracy of a Standalone Atrial Fibrillation Detection Algorithm Added to a Popular Wristband and Smartwatch: Prospective Diagnostic Accuracy Study", "journal": "Journal of Medical Internet Research", "year": 2023, "doi": "10.2196/44642", "pmid": "37234033", "url": "https://doi.org/10.2196/44642", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "stve2023", "citation": "Støve et al. (2023)", "title": "Assessment of Noninvasive Oxygen Saturation in Patients With COPD During Pulmonary Rehabilitation: Smartwatch versus Pulse Oximeter", "journal": "Respiratory Care", "year": 2023, "doi": "10.4187/respcare.10760", "pmid": "37193599", "url": "https://doi.org/10.4187/respcare.10760", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "theurl2023", "citation": "Theurl et al. (2023)", "title": "Smartwatch-derived heart rate variability: a head-to-head comparison with the gold standard in cardiovascular disease", "journal": "European Heart Journal - Digital Health", "year": 2023, "doi": "10.1093/ehjdh/ztad022", "pmid": "37265873", "url": "https://doi.org/10.1093/ehjdh/ztad022", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "walzel2023", "citation": "Walzel et al. (2023)", "title": "Evaluation of Leading Smartwatches for the Detection of Hypoxemia: Comparison to Reference Oximeter", "journal": "Sensors", "year": 2023, "doi": "10.3390/s23229164", "pmid": "38005550", "url": "https://doi.org/10.3390/s23229164", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "budig2022", "citation": "Budig et al. (2022)", "title": "Validity of Two Consumer Multisport Activity Tracker and One Accelerometer against Polysomnography for Measuring Sleep Parameters and Vital Data in a Laboratory Setting in Sleep Patients", "journal": "Sensors", "year": 2022, "doi": "10.3390/s22239540", "pmid": "36502241", "url": "https://doi.org/10.3390/s22239540", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "falter2022", "citation": "Falter et al. (2022)", "title": "Smartwatch-Based Blood Pressure Measurement Demonstrates Insufficient Accuracy", "journal": "Frontiers in Cardiovascular Medicine", "year": 2022, "doi": "10.3389/fcvm.2022.958212", "pmid": "35898281", "url": "https://doi.org/10.3389/fcvm.2022.958212", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "giggins2022", "citation": "Giggins et al. (2022)", "title": "Measurement of Heart Rate Using the Withings ScanWatch Device During Free-living Activities: Validation Study", "journal": "JMIR Formative Research", "year": 2022, "doi": "10.2196/34280", "pmid": "36048505", "url": "https://doi.org/10.2196/34280", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "henriksen2022", "citation": "Henriksen et al. (2022)", "title": "Polar Vantage and Oura Physical Activity and Sleep Trackers: Validation and Comparison Study", "journal": "JMIR Formative Research", "year": 2022, "doi": "10.2196/27248", "pmid": "35622397", "url": "https://doi.org/10.2196/27248", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "le2022", "citation": "Le et al. (2022)", "title": "Validity of three smartwatches in estimating energy expenditure during outdoor walking and running", "journal": "Frontiers in Physiology", "year": 2022, "doi": "10.3389/fphys.2022.995575", "pmid": "36225296", "url": "https://doi.org/10.3389/fphys.2022.995575", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "lubitz2022", "citation": "Lubitz et al. (2022)", "title": "Detection of Atrial Fibrillation in a Large Population Using Wearable Devices: The Fitbit Heart Study", "journal": "Circulation", "year": 2022, "doi": "10.1161/CIRCULATIONAHA.122.060291", "pmid": "36148649", "url": "https://doi.org/10.1161/CIRCULATIONAHA.122.060291", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "fitbit", "google" ], "funding_note": "Author affiliations include Fitbit and Google (PubMed record)" }, { "id": "miller2022", "citation": "Miller et al. (2022)", "title": "A Validation of Six Wearable Devices for Estimating Sleep, Heart Rate and Heart Rate Variability in Healthy Adults", "journal": "Sensors", "year": 2022, "doi": "10.3390/s22166317", "pmid": "36016077", "url": "https://doi.org/10.3390/s22166317", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "whoop" ], "funding_note": "COI: the authors' research group receives support (funding, equipment) from WHOOP Inc.; WHOOP not involved in the study" }, { "id": "nissen2022", "citation": "Nissen et al. (2022)", "title": "Heart Rate Measurement Accuracy of Fitbit Charge 4 and Samsung Galaxy Watch Active2: Device Evaluation Study", "journal": "JMIR Formative Research", "year": 2022, "doi": "10.2196/33635", "pmid": "35230250", "url": "https://doi.org/10.2196/33635", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "spaccarotella2022", "citation": "Spaccarotella et al. (2022)", "title": "Assessment of Non-Invasive Measurements of Oxygen Saturation and Heart Rate with an Apple Smartwatch: Comparison with a Standard Pulse Oximeter", "journal": "Journal of Clinical Medicine", "year": 2022, "doi": "10.3390/jcm11061467", "pmid": "35329793", "url": "https://doi.org/10.3390/jcm11061467", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "stve2022", "citation": "Støve et al. (2022)", "title": "Accuracy of the Apple Watch Series 6 and the Whoop Band 3.0 for assessing heart rate during resistance exercises", "journal": "Journal of Sports Sciences", "year": 2022, "doi": "10.1080/02640414.2023.2180160", "pmid": "36803578", "url": "https://doi.org/10.1080/02640414.2023.2180160", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "altini2021", "citation": "Altini et al. (2021)", "title": "The Promise of Sleep: A Multi-Sensor Approach for Accurate Sleep Stage Detection Using the Oura Ring", "journal": "Sensors", "year": 2021, "doi": "10.3390/s21134302", "pmid": "34201861", "url": "https://doi.org/10.3390/s21134302", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "oura" ], "funding_note": "COI: \"H.K. is employed by Oura Health, M.A. is an advisor at Oura Health.\"" }, { "id": "bellenger2021", "citation": "Bellenger et al. (2021)", "title": "Wrist-Based Photoplethysmography Assessment of Heart Rate and Heart Rate Variability: Validation of WHOOP", "journal": "Sensors", "year": 2021, "doi": "10.3390/s21103571", "pmid": "34065516", "url": "https://doi.org/10.3390/s21103571", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "whoop" ], "funding_note": "COI: an author's position is sponsored by WHOOP Inc. (arranged after data collection)" }, { "id": "chee2021", "citation": "Chee et al. (2021)", "title": "Multi-Night Validation of a Sleep Tracking Ring in Adolescents Compared with a Research Actigraph and Polysomnography", "journal": "Nature and Science of Sleep", "year": 2021, "doi": "10.2147/NSS.S286070", "pmid": "33623459", "url": "https://doi.org/10.2147/NSS.S286070", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "oura" ], "funding_note": "COI: rings supplied by Oura Health Oy for collection of PSG data for the company's internal use; authors report no other conflicts" }, { "id": "chinoy2021", "citation": "Chinoy et al. (2021)", "title": "Performance of seven consumer sleep-tracking devices compared with polysomnography", "journal": "Sleep", "year": 2021, "doi": "10.1093/sleep/zsaa291", "pmid": "33378539", "url": "https://doi.org/10.1093/sleep/zsaa291", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "lauterbach2021", "citation": "Lauterbach et al. (2021)", "title": "Accuracy and Reliability of Commercial Wrist-Worn Pulse Oximeter During Normobaric Hypoxia Exposure Under Resting Conditions", "journal": "Research Quarterly for Exercise and Sport", "year": 2021, "doi": "10.1080/02701367.2020.1759768", "pmid": "32633688", "url": "https://doi.org/10.1080/02701367.2020.1759768", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "miller2021", "citation": "Miller et al. (2021)", "title": "A Validation Study of a Commercial Wearable Device to Automatically Detect and Estimate Sleep", "journal": "Biosensors", "year": 2021, "doi": "10.3390/bios11060185", "pmid": "34201016", "url": "https://doi.org/10.3390/bios11060185", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "whoop" ], "funding_note": "COI: an author's position is sponsored by WHOOP Inc. (arranged after data collection)" }, { "id": "nuuttila2021", "citation": "Nuuttila et al. (2021)", "title": "Validity of the Wrist-Worn Polar Vantage V2 to Measure Heart Rate and Heart Rate Variability at Rest", "journal": "Sensors", "year": 2021, "doi": "10.3390/s22010137", "pmid": "35009680", "url": "https://doi.org/10.3390/s22010137", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "polar" ], "funding_note": "Maker named in disclosure or affiliations (PubMed record)" }, { "id": "schiefer2021", "citation": "Schiefer et al. (2021)", "title": "Validity of Peripheral Oxygen Saturation Measurements with the Garmin Fēnix® 5X Plus Wearable Device at 4559 m", "journal": "Sensors", "year": 2021, "doi": "10.3390/s21196363", "pmid": "34640680", "url": "https://doi.org/10.3390/s21196363", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "shumate2021", "citation": "Shumate et al. (2021)", "title": "Validity of the Polar Vantage M watch when measuring heart rate at different exercise intensities", "journal": "PeerJ", "year": 2021, "doi": "10.7717/peerj.10893", "pmid": "33614295", "url": "https://doi.org/10.7717/peerj.10893", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "stone2021", "citation": "Stone et al. (2021)", "title": "Assessing the Accuracy of Popular Commercial Technologies That Measure Resting Heart Rate and Heart Rate Variability", "journal": "Frontiers in Sports and Active Living", "year": 2021, "doi": "10.3389/fspor.2021.585870", "pmid": "33733234", "url": "https://doi.org/10.3389/fspor.2021.585870", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "asgarimehrabadi2020", "citation": "Asgari Mehrabadi et al. (2020)", "title": "Sleep Tracking of a Commercially Available Smart Ring and Smartwatch Against Medical-Grade Actigraphy in Everyday Settings: Instrument Validation Study", "journal": "JMIR mHealth and uHealth", "year": 2020, "doi": "10.2196/20465", "pmid": "33038869", "url": "https://doi.org/10.2196/20465", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "duking2020", "citation": "Düking et al. (2020)", "title": "Wrist-Worn Wearables for Monitoring Heart Rate and Energy Expenditure While Sitting or Performing Light-to-Vigorous Physical Activity: Validation Study", "journal": "JMIR mHealth and uHealth", "year": 2020, "doi": "10.2196/16716", "pmid": "32374274", "url": "https://doi.org/10.2196/16716", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "COI: one author previously funded by Polar Electro for an unrelated project" }, { "id": "kinnunen2020", "citation": "Kinnunen et al. (2020)", "title": "Feasible assessment of recovery and cardiovascular health: accuracy of nocturnal HR and HRV assessed via ring PPG in comparison to medical grade ECG", "journal": "Physiological Measurement", "year": 2020, "doi": "10.1088/1361-6579/ab840a", "pmid": "32217820", "url": "https://doi.org/10.1088/1361-6579/ab840a", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "oura" ], "funding_note": "Author affiliations include Oura Health (PubMed record)" }, { "id": "miller2020", "citation": "Miller et al. (2020)", "title": "A validation study of the WHOOP strap against polysomnography to assess sleep", "journal": "Journal of Sports Sciences", "year": 2020, "doi": "10.1080/02640414.2020.1797448", "pmid": "32713257", "url": "https://doi.org/10.1080/02640414.2020.1797448", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "dezambotti2019", "citation": "de Zambotti et al. (2019)", "title": "The Sleep of the Ring: Comparison of the ŌURA Sleep Tracker Against Polysomnography", "journal": "Behavioral Sleep Medicine", "year": 2019, "doi": "10.1080/15402002.2017.1300587", "pmid": "28323455", "url": "https://doi.org/10.1080/15402002.2017.1300587", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "passler2019", "citation": "Passler et al. (2019)", "title": "Validity of Wrist-Worn Activity Trackers for Estimating VO2max and Energy Expenditure", "journal": "International Journal of Environmental Research and Public Health", "year": 2019, "doi": "10.3390/ijerph16173037", "pmid": "31443347", "url": "https://doi.org/10.3390/ijerph16173037", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "perez2019", "citation": "Perez et al. (2019)", "title": "Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation", "journal": "New England Journal of Medicine", "year": 2019, "doi": "10.1056/NEJMoa1901183", "pmid": "31722151", "url": "https://doi.org/10.1056/NEJMoa1901183", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "industry", "industry_brands": [ "apple" ], "funding_note": "Abstract: \"Funded by Apple\"" }, { "id": "wasserlauf2019", "citation": "Wasserlauf et al. (2019)", "title": "Smartwatch Performance for the Detection and Quantification of Atrial Fibrillation", "journal": "Circulation: Arrhythmia and Electrophysiology", "year": 2019, "doi": "10.1161/CIRCEP.118.006834", "pmid": "31113234", "url": "https://doi.org/10.1161/CIRCEP.118.006834", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "bumgarner2018", "citation": "Bumgarner et al. (2018)", "title": "Smartwatch Algorithm for Automated Detection of Atrial Fibrillation", "journal": "Journal of the American College of Cardiology", "year": 2018, "doi": "10.1016/j.jacc.2018.03.003", "pmid": "29535065", "url": "https://doi.org/10.1016/j.jacc.2018.03.003", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "gillinov2017", "citation": "Gillinov et al. (2017)", "title": "Variable Accuracy of Wearable Heart Rate Monitors during Aerobic Exercise", "journal": "Medicine & Science in Sports & Exercise", "year": 2017, "doi": "10.1249/MSS.0000000000001284", "pmid": "28709155", "url": "https://doi.org/10.1249/MSS.0000000000001284", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" }, { "id": "shcherbina2017", "citation": "Shcherbina et al. (2017)", "title": "Accuracy in Wrist-Worn, Sensor-Based Measurements of Heart Rate and Energy Expenditure in a Diverse Cohort", "journal": "Journal of Personalized Medicine", "year": 2017, "doi": "10.3390/jpm7020003", "pmid": "28538708", "url": "https://doi.org/10.3390/jpm7020003", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "independent", "industry_brands": [], "funding_note": "Authors declare no competing interests" }, { "id": "wallen2016", "citation": "Wallen et al. (2016)", "title": "Accuracy of Heart Rate Watches: Implications for Weight Management", "journal": "PLOS ONE", "year": 2016, "doi": "10.1371/journal.pone.0154420", "pmid": "27232714", "url": "https://doi.org/10.1371/journal.pone.0154420", "peer_reviewed": true, "crossref_verified": "2026-10-17", "funding": "not_reported", "industry_brands": [], "funding_note": "No funding or competing-interest statement in the PubMed record" } ], "rows": [ { "id": "schyvens2025-fitbit-sense-sleep_stages-kappa", "study_id": "schyvens2025", "device": "Fitbit Sense", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.42, "value_text": "κ = 0.42", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 37, "n_note": "device subgroup of 62 participants", "population": "Adults, 52 M / 10 F, mean age 46.0 y", "skin_tone": null, "industry_funded": false, "quote": "Fitbit Sense (κ = 0.42", "location": "Abstract", "note": null, "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-fitbit-charge-5-sleep_stages-kappa", "study_id": "schyvens2025", "device": "Fitbit Charge 5", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-charge-5", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.41, "value_text": "κ = 0.41", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 39, "n_note": "device subgroup of 62 participants", "population": "Adults, 52 M / 10 F, mean age 46.0 y", "skin_tone": null, "industry_funded": false, "quote": "Fitbit Charge 5 (κ = 0.41", "location": "Abstract", "note": null, "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-apple-watch-series-8-sleep_stages-kappa", "study_id": "schyvens2025", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.53, "value_text": "κ = 0.53", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 62, "n_note": "device subgroup of 62 participants", "population": "Adults, 52 M / 10 F, mean age 46.0 y", "skin_tone": null, "industry_funded": false, "quote": "Apple Watch Series 8 (κ = 0.53", "location": "Abstract", "note": null, "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-fitbit-charge-5-sleep_wake-sensitivity_pct", "study_id": "schyvens2025", "device": "Fitbit Charge 5", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-charge-5", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": null, "value_text": "> 90% (all devices)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 62, "n_note": null, "population": "Adults, 52 M / 10 F, mean age 46.0 y", "skin_tone": null, "industry_funded": false, "quote": "All devices detected >90% of sleep epochs (ie, sensitivity), but showed lower specificity (29.39%-52.15%)", "location": "Abstract", "note": "Specificity across all six devices: 29.39%–52.15% (per-device values in full text)", "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-fitbit-sense-sleep_wake-sensitivity_pct", "study_id": "schyvens2025", "device": "Fitbit Sense", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": null, "value_text": "> 90% (all devices)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 62, "n_note": null, "population": "Adults, 52 M / 10 F, mean age 46.0 y", "skin_tone": null, "industry_funded": false, "quote": "All devices detected >90% of sleep epochs (ie, sensitivity), but showed lower specificity (29.39%-52.15%)", "location": "Abstract", "note": "Specificity across all six devices: 29.39%–52.15% (per-device values in full text)", "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-withings-scanwatch-sleep_wake-sensitivity_pct", "study_id": "schyvens2025", "device": "Withings ScanWatch", "brand": "withings", "brand_name": "Withings", "device_slug": "withings-scanwatch", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": null, "value_text": "> 90% (all devices)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 62, "n_note": null, "population": "Adults, 52 M / 10 F, mean age 46.0 y", "skin_tone": null, "industry_funded": false, "quote": "All devices detected >90% of sleep epochs (ie, sensitivity), but showed lower specificity (29.39%-52.15%)", "location": "Abstract", "note": "Specificity across all six devices: 29.39%–52.15% (per-device values in full text)", "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-garmin-vivosmart-4-sleep_wake-sensitivity_pct", "study_id": "schyvens2025", "device": "Garmin Vivosmart 4", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-vivosmart-4", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": null, "value_text": "> 90% (all devices)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 62, "n_note": null, "population": "Adults, 52 M / 10 F, mean age 46.0 y", "skin_tone": null, "industry_funded": false, "quote": "All devices detected >90% of sleep epochs (ie, sensitivity), but showed lower specificity (29.39%-52.15%)", "location": "Abstract", "note": "Specificity across all six devices: 29.39%–52.15% (per-device values in full text)", "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-whoop-4-0-sleep_wake-sensitivity_pct", "study_id": "schyvens2025", "device": "WHOOP 4.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-4", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": null, "value_text": "> 90% (all devices)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 62, "n_note": null, "population": "Adults, 52 M / 10 F, mean age 46.0 y", "skin_tone": null, "industry_funded": false, "quote": "All devices detected >90% of sleep epochs (ie, sensitivity), but showed lower specificity (29.39%-52.15%)", "location": "Abstract", "note": "Specificity across all six devices: 29.39%–52.15% (per-device values in full text)", "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-apple-watch-series-8-sleep_wake-sensitivity_pct", "study_id": "schyvens2025", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": null, "value_text": "> 90% (all devices)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 62, "n_note": null, "population": "Adults, 52 M / 10 F, mean age 46.0 y", "skin_tone": null, "industry_funded": false, "quote": "All devices detected >90% of sleep epochs (ie, sensitivity), but showed lower specificity (29.39%-52.15%)", "location": "Abstract", "note": "Specificity across all six devices: 29.39%–52.15% (per-device values in full text)", "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "robbins2024-oura-ring-gen3-sleep_stages-sensitivity_pct", "study_id": "robbins2024", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "sleep_stages", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": null, "value_text": "76.0–79.5% (range across stages)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Inpatient, 1 night", "n": 35, "n_note": null, "population": "Adults 20–50 y without sleep disorder", "skin_tone": null, "industry_funded": true, "quote": "Oura ring sensitivity 76.0-79.5%", "location": "Abstract", "note": null, "doi": "10.3390/s24206532" }, { "id": "robbins2024-oura-ring-gen3-sleep_wake-sensitivity_pct", "study_id": "robbins2024", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 95, "value_text": "≥ 95%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Inpatient, 1 night", "n": 35, "n_note": null, "population": "Adults 20–50 y without sleep disorder", "skin_tone": null, "industry_funded": true, "quote": "For detecting sleep vs. wake, the sensitivity was ≥95% for all devices", "location": "Abstract", "note": null, "doi": "10.3390/s24206532" }, { "id": "robbins2024-fitbit-sense-2-sleep_stages-sensitivity_pct", "study_id": "robbins2024", "device": "Fitbit Sense 2", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense-2", "metric": "sleep_stages", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": null, "value_text": "61.7–78.0% (range across stages)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Inpatient, 1 night", "n": 35, "n_note": null, "population": "Adults 20–50 y without sleep disorder", "skin_tone": null, "industry_funded": false, "quote": "Fitbit sensitivity 61.7-78.0%", "location": "Abstract", "note": null, "doi": "10.3390/s24206532" }, { "id": "robbins2024-fitbit-sense-2-sleep_wake-sensitivity_pct", "study_id": "robbins2024", "device": "Fitbit Sense 2", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense-2", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 95, "value_text": "≥ 95%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Inpatient, 1 night", "n": 35, "n_note": null, "population": "Adults 20–50 y without sleep disorder", "skin_tone": null, "industry_funded": false, "quote": "For detecting sleep vs. wake, the sensitivity was ≥95% for all devices", "location": "Abstract", "note": null, "doi": "10.3390/s24206532" }, { "id": "robbins2024-apple-watch-series-8-sleep_stages-sensitivity_pct", "study_id": "robbins2024", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "sleep_stages", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": null, "value_text": "50.5–86.1% (range across stages)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Inpatient, 1 night", "n": 35, "n_note": null, "population": "Adults 20–50 y without sleep disorder", "skin_tone": null, "industry_funded": false, "quote": "Apple sensitivity 50.5-86.1%", "location": "Abstract", "note": null, "doi": "10.3390/s24206532" }, { "id": "robbins2024-apple-watch-series-8-sleep_wake-sensitivity_pct", "study_id": "robbins2024", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 95, "value_text": "≥ 95%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Inpatient, 1 night", "n": 35, "n_note": null, "population": "Adults 20–50 y without sleep disorder", "skin_tone": null, "industry_funded": false, "quote": "For detecting sleep vs. wake, the sensitivity was ≥95% for all devices", "location": "Abstract", "note": null, "doi": "10.3390/s24206532" }, { "id": "robbins2024-fitbit-sense-2-sleep_stages-bias", "study_id": "robbins2024", "device": "Fitbit Sense 2", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense-2", "metric": "sleep_stages", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -15, "value_text": "Deep sleep −15 min", "unit": "min", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "deep sleep duration", "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Inpatient, 1 night", "n": 35, "n_note": null, "population": "Adults 20–50 y without sleep disorder", "skin_tone": null, "industry_funded": false, "quote": "underestimated deep (15 min; p < 0.001) sleep", "location": "Abstract", "note": null, "doi": "10.3390/s24206532" }, { "id": "robbins2024-apple-watch-series-8-sleep_stages-bias", "study_id": "robbins2024", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "sleep_stages", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -43, "value_text": "Deep sleep −43 min", "unit": "min", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "deep sleep duration", "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Inpatient, 1 night", "n": 35, "n_note": null, "population": "Adults 20–50 y without sleep disorder", "skin_tone": null, "industry_funded": false, "quote": "deep (43 min; p < 0.001) sleep", "location": "Abstract", "note": null, "doi": "10.3390/s24206532" }, { "id": "robbins2024-oura-ring-gen3-sleep_stages-finding", "study_id": "robbins2024", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "sleep_stages", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Not different from PSG for wake, light, deep or REM", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Inpatient, 1 night", "n": 35, "n_note": null, "population": "Adults 20–50 y without sleep disorder", "skin_tone": null, "industry_funded": true, "quote": "The Oura ring was not different from PSG in terms of wake, light sleep, deep sleep, or REM sleep estimation", "location": "Abstract", "note": null, "doi": "10.3390/s24206532" }, { "id": "svensson2024-oura-ring-gen3-ossa-2-0-sleep_wake-agreement_pct", "study_id": "svensson2024", "device": "Oura Ring Gen3 (OSSA 2.0)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "sleep_wake", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 91.7, "value_text": "91.7–91.8%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Home ambulatory PSG, up to 3 nights", "n": 96, "n_note": null, "population": "Healthy Japanese adults 20–70 y, 421,045 epochs", "skin_tone": null, "industry_funded": true, "quote": "accuracy of 91.7 %-91.8 %", "location": "Abstract", "note": null, "doi": "10.1016/j.sleep.2024.01.020" }, { "id": "svensson2024-oura-ring-gen3-ossa-2-0-sleep_wake-sensitivity_pct", "study_id": "svensson2024", "device": "Oura Ring Gen3 (OSSA 2.0)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 94.4, "value_text": "94.4–94.5%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Home ambulatory PSG, up to 3 nights", "n": 96, "n_note": null, "population": "Healthy Japanese adults 20–70 y, 421,045 epochs", "skin_tone": null, "industry_funded": true, "quote": "sensitivity of 94.4 %-94.5 %", "location": "Abstract", "note": null, "doi": "10.1016/j.sleep.2024.01.020" }, { "id": "svensson2024-oura-ring-gen3-ossa-2-0-sleep_wake-specificity_pct", "study_id": "svensson2024", "device": "Oura Ring Gen3 (OSSA 2.0)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "sleep_wake", "statistic": "specificity_pct", "statistic_label": "Specificity", "value": 73, "value_text": "73.0–74.6%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Home ambulatory PSG, up to 3 nights", "n": 96, "n_note": null, "population": "Healthy Japanese adults 20–70 y, 421,045 epochs", "skin_tone": null, "industry_funded": true, "quote": "specificity of 73.0 %-74.6 %", "location": "Abstract", "note": null, "doi": "10.1016/j.sleep.2024.01.020" }, { "id": "svensson2024-oura-ring-gen3-ossa-2-0-sleep_stages-agreement_pct", "study_id": "svensson2024", "device": "Oura Ring Gen3 (OSSA 2.0)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": null, "value_text": "75.5% (light) to 90.6% (REM), per-stage", "unit": "%", "higher_is_better": true, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Home ambulatory PSG, up to 3 nights", "n": 96, "n_note": null, "population": "Healthy Japanese adults 20–70 y, 421,045 epochs", "skin_tone": null, "industry_funded": true, "quote": "Sleep staging accuracy ranged between 75.5 % (light sleep) and 90.6 % (REM sleep)", "location": "Abstract", "note": null, "doi": "10.1016/j.sleep.2024.01.020" }, { "id": "miller2020-whoop-strap-2-0-era-sleep_wake-agreement_pct", "study_id": "miller2020", "device": "WHOOP (strap, 2.0 era)", "brand": "whoop", "brand_name": "WHOOP", "device_slug": null, "metric": "sleep_wake", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 89, "value_text": "89% (κ 0.49)", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": "κ 0.49; sensitivity 95%, specificity 51%", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 10-day protocol, 86 sleeps", "n": 12, "n_note": null, "population": "Healthy adults, 6 F / 6 M, 22.9 y", "skin_tone": null, "industry_funded": false, "quote": "the agreement, sensitivity to sleep, specificity for wake, and Cohen's kappa were 89%, 95%, 51%, and 0.49", "location": "Abstract", "note": null, "doi": "10.1080/02640414.2020.1797448" }, { "id": "miller2020-whoop-strap-2-0-era-sleep_stages-agreement_pct", "study_id": "miller2020", "device": "WHOOP (strap, 2.0 era)", "brand": "whoop", "brand_name": "WHOOP", "device_slug": null, "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 64, "value_text": "64% (κ 0.47)", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": "κ 0.47", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 10-day protocol, 86 sleeps", "n": 12, "n_note": null, "population": "Healthy adults, 6 F / 6 M, 22.9 y", "skin_tone": null, "industry_funded": false, "quote": "For 4-stage categorisation, the agreement, sensitivity to light sleep, SWS, REM, and wake, and Cohen's kappa were 64%, 62%, 68%, 70%, 51%, and 0.47", "location": "Abstract", "note": null, "doi": "10.1080/02640414.2020.1797448" }, { "id": "miller2020-whoop-strap-2-0-era-sleep_stages-kappa", "study_id": "miller2020", "device": "WHOOP (strap, 2.0 era)", "brand": "whoop", "brand_name": "WHOOP", "device_slug": null, "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.47, "value_text": "κ = 0.47", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 10-day protocol, 86 sleeps", "n": 12, "n_note": null, "population": "Healthy adults, 6 F / 6 M, 22.9 y", "skin_tone": null, "industry_funded": false, "quote": "For 4-stage categorisation, the agreement, sensitivity to light sleep, SWS, REM, and wake, and Cohen's kappa were 64%, 62%, 68%, 70%, 51%, and 0.47", "location": "Abstract", "note": null, "doi": "10.1080/02640414.2020.1797448" }, { "id": "miller2020-whoop-strap-2-0-era-sleep_wake-kappa", "study_id": "miller2020", "device": "WHOOP (strap, 2.0 era)", "brand": "whoop", "brand_name": "WHOOP", "device_slug": null, "metric": "sleep_wake", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.49, "value_text": "κ = 0.49", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 10-day protocol, 86 sleeps", "n": 12, "n_note": null, "population": "Healthy adults, 6 F / 6 M, 22.9 y", "skin_tone": null, "industry_funded": false, "quote": "the agreement, sensitivity to sleep, specificity for wake, and Cohen's kappa were 89%, 95%, 51%, and 0.49", "location": "Abstract", "note": null, "doi": "10.1080/02640414.2020.1797448" }, { "id": "miller2020-whoop-strap-2-0-era-sleep_tst-bias", "study_id": "miller2020", "device": "WHOOP (strap, 2.0 era)", "brand": "whoop", "brand_name": "WHOOP", "device_slug": null, "metric": "sleep_tst", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": 8.2, "value_text": "+8.2 ± 32.9 min (n.s.)", "unit": "min", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 10-day protocol, 86 sleeps", "n": 12, "n_note": null, "population": "Healthy adults, 6 F / 6 M, 22.9 y", "skin_tone": null, "industry_funded": false, "quote": "WHOOP overestimated total sleep time by 8.2 ± 32.9 minutes compared to polysomnography", "location": "Abstract", "note": null, "doi": "10.1080/02640414.2020.1797448" }, { "id": "miller2021-whoop-auto-detect-sleep_wake-agreement_pct", "study_id": "miller2021", "device": "WHOOP (auto-detect)", "brand": "whoop", "brand_name": "WHOOP", "device_slug": null, "metric": "sleep_wake", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 86, "value_text": "86%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 9 nights, 54 sleeps", "n": 6, "n_note": null, "population": "Healthy adults 23.0 y", "skin_tone": null, "industry_funded": true, "quote": "For WHOOP-AUTO, sensitivity for sleep, wake, and agreement for two-stage and four-stage categorisation of sleep were 90%, 60%, 86% and 63%", "location": "Abstract", "note": null, "doi": "10.3390/bios11060185" }, { "id": "miller2021-whoop-auto-detect-sleep_stages-agreement_pct", "study_id": "miller2021", "device": "WHOOP (auto-detect)", "brand": "whoop", "brand_name": "WHOOP", "device_slug": null, "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 63, "value_text": "63%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 9 nights, 54 sleeps", "n": 6, "n_note": null, "population": "Healthy adults 23.0 y", "skin_tone": null, "industry_funded": true, "quote": "For WHOOP-AUTO, sensitivity for sleep, wake, and agreement for two-stage and four-stage categorisation of sleep were 90%, 60%, 86% and 63%", "location": "Abstract", "note": null, "doi": "10.3390/bios11060185" }, { "id": "searles2026-fitbit-sense-2-sleep_tst-bias", "study_id": "searles2026", "device": "Fitbit Sense 2", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense-2", "metric": "sleep_tst", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -74.5, "value_text": "−74.5 min (older adults)", "unit": "min", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "1 night", "n": 19, "n_note": null, "population": "Older adults 56–80 y (subgroup of 32)", "skin_tone": null, "industry_funded": false, "quote": "Fitbit bias = -74.5 minutes", "location": "Abstract", "note": null, "doi": "10.1093/sleepadvances/zpag006" }, { "id": "searles2026-oura-ring-sleep_tst-bias", "study_id": "searles2026", "device": "Oura Ring", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring", "metric": "sleep_tst", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -75.5, "value_text": "−75.5 min (older adults)", "unit": "min", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "1 night", "n": 19, "n_note": null, "population": "Older adults 56–80 y (subgroup of 32)", "skin_tone": null, "industry_funded": false, "quote": "Oura bias = -75.5", "location": "Abstract", "note": null, "doi": "10.1093/sleepadvances/zpag006" }, { "id": "chinoy2021-fitbit-alta-hr-sleep_wake-finding", "study_id": "chinoy2021", "device": "Fitbit Alta HR", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": null, "metric": "sleep_wake", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "As good as or better than actigraphy", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 3 nights incl. disrupted night", "n": 34, "n_note": null, "population": "Healthy young adults, 22 women, 28.1 y", "skin_tone": null, "industry_funded": false, "quote": "Most devices (Fatigue Science Readiband, Fitbit Alta HR, EarlySense Live, ResMed S+, SleepScore Max) performed as well as or better than actigraphy on sleep/wake performance measures", "location": "Abstract", "note": null, "doi": "10.1093/sleep/zsaa291" }, { "id": "chinoy2021-garmin-fenix-5s-sleep_wake-finding", "study_id": "chinoy2021", "device": "Garmin Fenix 5S", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "sleep_wake", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Worse than actigraphy", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 3 nights incl. disrupted night", "n": 34, "n_note": null, "population": "Healthy young adults, 22 women, 28.1 y", "skin_tone": null, "industry_funded": false, "quote": "while the Garmin devices performed worse", "location": "Abstract", "note": null, "doi": "10.1093/sleep/zsaa291" }, { "id": "chinoy2021-garmin-vivosmart-3-sleep_wake-finding", "study_id": "chinoy2021", "device": "Garmin Vivosmart 3", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "sleep_wake", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Worse than actigraphy", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 3 nights incl. disrupted night", "n": 34, "n_note": null, "population": "Healthy young adults, 22 women, 28.1 y", "skin_tone": null, "industry_funded": false, "quote": "while the Garmin devices performed worse", "location": "Abstract", "note": null, "doi": "10.1093/sleep/zsaa291" }, { "id": "dezambotti2019-oura-ring-gen1-sleep_wake-sensitivity_pct", "study_id": "dezambotti2019", "device": "Oura Ring (Gen1)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen1", "metric": "sleep_wake", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 96, "value_text": "96%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 41, "n_note": null, "population": "Healthy adolescents and young adults, 17.2 y", "skin_tone": null, "industry_funded": false, "quote": "96% sensitivity to detect sleep", "location": "Abstract", "note": null, "doi": "10.1080/15402002.2017.1300587" }, { "id": "dezambotti2019-oura-ring-gen1-sleep_wake-specificity_pct", "study_id": "dezambotti2019", "device": "Oura Ring (Gen1)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen1", "metric": "sleep_wake", "statistic": "specificity_pct", "statistic_label": "Specificity", "value": 48, "value_text": "48%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 41, "n_note": null, "population": "Healthy adolescents and young adults, 17.2 y", "skin_tone": null, "industry_funded": false, "quote": "Specificity in detecting wake was 48%", "location": "Abstract", "note": null, "doi": "10.1080/15402002.2017.1300587" }, { "id": "chee2021-oura-ring-gen2-sleep_tst-bias", "study_id": "chee2021", "device": "Oura Ring (Gen2)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "sleep_tst", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -32.8, "value_text": "−32.8 to −47.3 min", "unit": "min", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, multiple nights, 3 sleep-opportunity conditions", "n": 53, "n_note": null, "population": "Adolescents 15–19 y, 28 F", "skin_tone": null, "industry_funded": true, "quote": "Oura consistently underestimated TST by an average of 32.8 to 47.3 minutes", "location": "Abstract", "note": null, "doi": "10.2147/NSS.S286070" }, { "id": "chee2021-oura-ring-gen2-sleep_wake-agreement_pct", "study_id": "chee2021", "device": "Oura Ring (Gen2)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "sleep_wake", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 88, "value_text": "0.88–0.89", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, multiple nights, 3 sleep-opportunity conditions", "n": 53, "n_note": null, "population": "Adolescents 15–19 y, 28 F", "skin_tone": null, "industry_funded": true, "quote": "EBE analyses demonstrated excellent sleep-wake accuracies, specificities, and sensitivities - between 0.88 and 0.89", "location": "Abstract", "note": null, "doi": "10.2147/NSS.S286070" }, { "id": "herberger2025-oura-ring-sleep_stages-agreement_pct", "study_id": "herberger2025", "device": "Oura Ring", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring", "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 53.18, "value_text": "53.18%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "University sleep laboratory, clinical patients", "n": null, "n_note": null, "population": "Sleep-lab patients with sleep and other medical conditions", "skin_tone": null, "industry_funded": false, "quote": "the Oura and SleepOn ring performed similarly (53.18% and 50.48% accuracy)", "location": "Abstract", "note": null, "doi": "10.1038/s41598-025-93774-z" }, { "id": "herberger2025-oura-ring-sleep_wake-agreement_pct", "study_id": "herberger2025", "device": "Oura Ring", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring", "metric": "sleep_wake", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 85, "value_text": "~85%", "unit": "%", "higher_is_better": true, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "University sleep laboratory, clinical patients", "n": null, "n_note": null, "population": "Sleep-lab patients with sleep and other medical conditions", "skin_tone": null, "industry_funded": false, "quote": "Sleep/Wake distinction of the Oura and SleepOn rings reached similar performance as previously reported for healthy individuals (~ 85% accuracy)", "location": "Abstract", "note": null, "doi": "10.1038/s41598-025-93774-z" }, { "id": "herberger2025-oura-ring-sleep_tst-finding", "study_id": "herberger2025", "device": "Oura Ring", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring", "metric": "sleep_tst", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Group-level TST difference < 12 min", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "University sleep laboratory, clinical patients", "n": null, "n_note": null, "population": "Sleep-lab patients with sleep and other medical conditions", "skin_tone": null, "industry_funded": false, "quote": "TST differences between rings and gold standard were below 12 min for the Oura ring", "location": "Abstract", "note": null, "doi": "10.1038/s41598-025-93774-z" }, { "id": "asgarimehrabadi2020-oura-ring-gen2-sleep_tst-r", "study_id": "asgarimehrabadi2020", "device": "Oura Ring (Gen2)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "sleep_tst", "statistic": "r", "statistic_label": "Pearson correlation", "value": 0.86, "value_text": "r = 0.86", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Research actigraphy", "reference_class": "actigraphy", "setting": "Home, 7 days", "n": 45, "n_note": null, "population": "Healthy adults, 23 W / 22 M", "skin_tone": null, "industry_funded": false, "quote": "We found significant correlations between the ring's and actigraphy's TST (r=0.86; P<.001)", "location": "Abstract", "note": null, "doi": "10.2196/20465" }, { "id": "asgarimehrabadi2020-samsung-gear-sport-sleep_tst-r", "study_id": "asgarimehrabadi2020", "device": "Samsung Gear Sport", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-gear-sport", "metric": "sleep_tst", "statistic": "r", "statistic_label": "Pearson correlation", "value": 0.59, "value_text": "r = 0.59", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Research actigraphy", "reference_class": "actigraphy", "setting": "Home, 7 days", "n": 45, "n_note": null, "population": "Healthy adults, 23 W / 22 M", "skin_tone": null, "industry_funded": false, "quote": "Comparing the watch with actigraphy showed a significant correlation in TST (r=0.59; P<.001)", "location": "Abstract", "note": null, "doi": "10.2196/20465" }, { "id": "henriksen2022-oura-ring-gen2-hr_rest-r", "study_id": "henriksen2022", "device": "Oura Ring (Gen2)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "hr_rest", "statistic": "r", "statistic_label": "Pearson correlation", "value": 0.9, "value_text": "r = 0.90", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Actiheart (ECG + accelerometer)", "reference_class": "actiheart", "setting": "Free-living, up to 7 days", "n": 21, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "Oura ring-derived resting heart rates had a very strong correlation (P<.001) with the Actiheart-derived resting heart rates (r=0.9, 95% CI 0.85-0.96)", "location": "Abstract", "note": null, "doi": "10.2196/27248" }, { "id": "henriksen2022-oura-ring-gen2-hr_rest-mape_pct", "study_id": "henriksen2022", "device": "Oura Ring (Gen2)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "hr_rest", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 3, "value_text": "3%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Actiheart (ECG + accelerometer)", "reference_class": "actiheart", "setting": "Free-living, up to 7 days", "n": 21, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "Oura ring-derived sleep duration (10%) and resting heart rate (3%)", "location": "Abstract", "note": null, "doi": "10.2196/27248" }, { "id": "henriksen2022-oura-ring-gen2-energy-r", "study_id": "henriksen2022", "device": "Oura Ring (Gen2)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "energy", "statistic": "r", "statistic_label": "Pearson correlation", "value": 0.7, "value_text": "r = 0.70", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": "total energy expenditure", "reference": "Actiheart / ActiGraph", "reference_class": "actiheart", "setting": "Free-living, up to 7 days", "n": 21, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "Oura: r=0.70, 95% CI 0.51-0.83)", "location": "Abstract", "note": null, "doi": "10.2196/27248" }, { "id": "henriksen2022-polar-vantage-energy-r", "study_id": "henriksen2022", "device": "Polar Vantage", "brand": "polar", "brand_name": "Polar", "device_slug": null, "metric": "energy", "statistic": "r", "statistic_label": "Pearson correlation", "value": 0.69, "value_text": "r = 0.69", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": "total energy expenditure", "reference": "Actiheart / ActiGraph", "reference_class": "actiheart", "setting": "Free-living, up to 7 days", "n": 21, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "total energy expenditure (Polar: r=0.69, 95% CI 0.48-0.88", "location": "Abstract", "note": null, "doi": "10.2196/27248" }, { "id": "dial2025-oura-ring-gen3-hr_sleep-mape_pct", "study_id": "dial2025", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "hr_sleep", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 1.67, "value_text": "1.67%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.97", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Oura Gen 3 (Lin's Concordance [CCC] = 0.97, mean absolute percentage error [MAPE] = 1.67", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-oura-ring-gen3-hr_sleep-ccc", "study_id": "dial2025", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "hr_sleep", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.97, "value_text": "0.97", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Oura Gen 3 (Lin's Concordance [CCC] = 0.97, mean absolute percentage error [MAPE] = 1.67", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-oura-ring-4-hr_sleep-mape_pct", "study_id": "dial2025", "device": "Oura Ring 4", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-4", "metric": "hr_sleep", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 1.94, "value_text": "1.94%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.98", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Gen 4 (CCC = 0.98, MAPE = 1.94", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-oura-ring-4-hr_sleep-ccc", "study_id": "dial2025", "device": "Oura Ring 4", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-4", "metric": "hr_sleep", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.98, "value_text": "0.98", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Gen 4 (CCC = 0.98, MAPE = 1.94", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-polar-grit-x-pro-hr_sleep-mape_pct", "study_id": "dial2025", "device": "Polar Grit X Pro", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-grit-x-pro", "metric": "hr_sleep", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 2.71, "value_text": "2.71%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.86", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Polar's poor (CCC = 0.86, MAPE = 2.71", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-polar-grit-x-pro-hr_sleep-ccc", "study_id": "dial2025", "device": "Polar Grit X Pro", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-grit-x-pro", "metric": "hr_sleep", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.86, "value_text": "0.86", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Polar's poor (CCC = 0.86, MAPE = 2.71", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-whoop-4-0-hr_sleep-mape_pct", "study_id": "dial2025", "device": "WHOOP 4.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-4", "metric": "hr_sleep", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 3, "value_text": "3.00%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.91", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "WHOOP's moderate agreement (CCC = 0.91, MAPE = 3.00", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-whoop-4-0-hr_sleep-ccc", "study_id": "dial2025", "device": "WHOOP 4.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-4", "metric": "hr_sleep", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.91, "value_text": "0.91", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "WHOOP's moderate agreement (CCC = 0.91, MAPE = 3.00", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-oura-ring-4-hrv_rmssd-mape_pct", "study_id": "dial2025", "device": "Oura Ring 4", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-4", "metric": "hrv_rmssd", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 5.96, "value_text": "5.96%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.99", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Oura Gen 4 (CCC = 0.99, MAPE = 5.96", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-oura-ring-4-hrv_rmssd-ccc", "study_id": "dial2025", "device": "Oura Ring 4", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-4", "metric": "hrv_rmssd", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.99, "value_text": "0.99", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Oura Gen 4 (CCC = 0.99, MAPE = 5.96", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-oura-ring-gen3-hrv_rmssd-mape_pct", "study_id": "dial2025", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "hrv_rmssd", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 7.15, "value_text": "7.15%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.97", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Oura Gen 3 (CCC = 0.97, MAPE = 7.15", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-oura-ring-gen3-hrv_rmssd-ccc", "study_id": "dial2025", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "hrv_rmssd", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.97, "value_text": "0.97", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Oura Gen 3 (CCC = 0.97, MAPE = 7.15", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-whoop-4-0-hrv_rmssd-mape_pct", "study_id": "dial2025", "device": "WHOOP 4.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-4", "metric": "hrv_rmssd", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 8.17, "value_text": "8.17%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.94", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "WHOOP showed moderate accuracy (CCC = 0.94, MAPE = 8.17", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-whoop-4-0-hrv_rmssd-ccc", "study_id": "dial2025", "device": "WHOOP 4.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-4", "metric": "hrv_rmssd", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.94, "value_text": "0.94", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "WHOOP showed moderate accuracy (CCC = 0.94, MAPE = 8.17", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-garmin-fenix-6-hrv_rmssd-mape_pct", "study_id": "dial2025", "device": "Garmin Fenix 6", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-fenix-6", "metric": "hrv_rmssd", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 10.52, "value_text": "10.52%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.87", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Garmin (CCC = 0.87, MAPE = 10.52", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-garmin-fenix-6-hrv_rmssd-ccc", "study_id": "dial2025", "device": "Garmin Fenix 6", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-fenix-6", "metric": "hrv_rmssd", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.87, "value_text": "0.87", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Garmin (CCC = 0.87, MAPE = 10.52", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-polar-grit-x-pro-hrv_rmssd-mape_pct", "study_id": "dial2025", "device": "Polar Grit X Pro", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-grit-x-pro", "metric": "hrv_rmssd", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 16.32, "value_text": "16.32%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.82", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Polar (CCC = 0.82, MAPE = 16.32", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "dial2025-polar-grit-x-pro-hrv_rmssd-ccc", "study_id": "dial2025", "device": "Polar Grit X Pro", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-grit-x-pro", "metric": "hrv_rmssd", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.82, "value_text": "0.82", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Home, during sleep, 536 nights", "n": 13, "n_note": null, "population": "Healthy adults, 6 F", "skin_tone": null, "industry_funded": false, "quote": "Polar (CCC = 0.82, MAPE = 16.32", "location": "Abstract", "note": null, "doi": "10.14814/phy2.70527" }, { "id": "kinnunen2020-oura-ring-gen1-2-hr_sleep-bias", "study_id": "kinnunen2020", "device": "Oura Ring (Gen1/2)", "brand": "oura", "brand_name": "Oura", "device_slug": null, "metric": "hr_sleep", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -0.63, "value_text": "−0.63 bpm (r² 0.996)", "unit": "bpm", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Nocturnal", "n": 49, "n_note": null, "population": "Adults 15–72 y", "skin_tone": null, "industry_funded": true, "quote": "with a mean bias of -0.63 bpm and -1.2 ms", "location": "Abstract", "note": null, "doi": "10.1088/1361-6579/ab840a" }, { "id": "kinnunen2020-oura-ring-gen1-2-hrv_rmssd-bias", "study_id": "kinnunen2020", "device": "Oura Ring (Gen1/2)", "brand": "oura", "brand_name": "Oura", "device_slug": null, "metric": "hrv_rmssd", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -1.2, "value_text": "−1.2 ms (r² 0.980)", "unit": "ms", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Nocturnal", "n": 49, "n_note": null, "population": "Adults 15–72 y", "skin_tone": null, "industry_funded": true, "quote": "with a mean bias of -0.63 bpm and -1.2 ms", "location": "Abstract", "note": null, "doi": "10.1088/1361-6579/ab840a" }, { "id": "stone2021-oura-ring-hrv_rmssd-mape_pct", "study_id": "stone2021", "device": "Oura Ring", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring", "metric": "hrv_rmssd", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 6.84, "value_text": "6.84%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.91", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Resting state", "n": 5, "n_note": null, "population": "Healthy young adults, 148 trials", "skin_tone": null, "industry_funded": false, "quote": "OURA (6.84%; CCC: 0.91)", "location": "Abstract", "note": null, "doi": "10.3389/fspor.2021.585870" }, { "id": "stone2021-hrv4training-app-hrv_rmssd-mape_pct", "study_id": "stone2021", "device": "HRV4Training (app)", "brand": "other", "brand_name": "Other", "device_slug": null, "metric": "hrv_rmssd", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 4.1, "value_text": "4.10%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.98", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Resting state", "n": 5, "n_note": null, "population": "Healthy young adults, 148 trials", "skin_tone": null, "industry_funded": false, "quote": "HRV4Training (4.10%; CCC: 0.98)", "location": "Abstract", "note": null, "doi": "10.3389/fspor.2021.585870" }, { "id": "stone2021-camerahrv-app-hrv_rmssd-mape_pct", "study_id": "stone2021", "device": "CameraHRV (app)", "brand": "other", "brand_name": "Other", "device_slug": null, "metric": "hrv_rmssd", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 112.36, "value_text": "112.36%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.04", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Resting state", "n": 5, "n_note": null, "population": "Healthy young adults, 148 trials", "skin_tone": null, "industry_funded": false, "quote": "CameraHRV [112.36%, concordance correlation coefficient (CCC): 0.04]", "location": "Abstract", "note": null, "doi": "10.3389/fspor.2021.585870" }, { "id": "stone2021-hrv4training-app-hr_rest-mape_pct", "study_id": "stone2021", "device": "HRV4Training (app)", "brand": "other", "brand_name": "Other", "device_slug": null, "metric": "hr_rest", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 2.34, "value_text": "2.34%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Resting state", "n": 5, "n_note": null, "population": "Healthy young adults, 148 trials", "skin_tone": null, "industry_funded": false, "quote": "HRV4Training, 2.34%", "location": "Abstract", "note": null, "doi": "10.3389/fspor.2021.585870" }, { "id": "stone2021-camerahrv-app-hr_rest-mape_pct", "study_id": "stone2021", "device": "CameraHRV (app)", "brand": "other", "brand_name": "Other", "device_slug": null, "metric": "hr_rest", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 17.26, "value_text": "17.26%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Resting state", "n": 5, "n_note": null, "population": "Healthy young adults, 148 trials", "skin_tone": null, "industry_funded": false, "quote": "CameraHRV (17.26%)", "location": "Abstract", "note": null, "doi": "10.3389/fspor.2021.585870" }, { "id": "bellenger2021-whoop-hr_rest-bias", "study_id": "bellenger2021", "device": "WHOOP", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-strap", "metric": "hr_rest", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": 0.39, "value_text": "≤ 0.39 ± 0.38%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Rest, 15 opportunities", "n": null, "n_note": null, "population": "See full text", "skin_tone": null, "industry_funded": true, "quote": "bias (≤0.39 ± 0.38%) and LOA (≤1.56%) in HR", "location": "Abstract", "note": null, "doi": "10.3390/s21103571" }, { "id": "bellenger2021-whoop-hrv_rmssd-bias", "study_id": "bellenger2021", "device": "WHOOP", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-strap", "metric": "hrv_rmssd", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": 1.66, "value_text": "Ln RMSSD 1.66 ± 1.80% (LoA ±5.93%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Rest, 15 opportunities", "n": null, "n_note": null, "population": "See full text", "skin_tone": null, "industry_funded": true, "quote": "For Ln RMSSD, bias (1.66 ± 1.80%) and LOA (±5.93%)", "location": "Abstract", "note": null, "doi": "10.3390/s21103571" }, { "id": "stve2022-apple-watch-series-6-hr_exercise-finding", "study_id": "stve2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "High agreement in squat, deadlift, cable row (rho > 0.832)", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Resistance exercise (5 exercises)", "n": 29, "n_note": null, "population": "Adults 19–37 y, 16 F", "skin_tone": null, "industry_funded": false, "quote": "The Apple Watch had high agreement with the Polar H10 during Barbell Back Squats, Barbell Deadlift, and Seated Cable Rows (rho > 0.832)", "location": "Abstract", "note": null, "doi": "10.1080/02640414.2023.2180160" }, { "id": "stve2022-whoop-3-0-hr_exercise-finding", "study_id": "stve2022", "device": "WHOOP 3.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-3", "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "High agreement only in squats; low in rows and burpees", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Resistance exercise (5 exercises)", "n": 29, "n_note": null, "population": "Adults 19–37 y, 16 F", "skin_tone": null, "industry_funded": false, "quote": "The Whoop Band 3.0 had high agreement with the Polar H10 during Barbell Back Squats (r > 0.697)", "location": "Abstract", "note": null, "doi": "10.1080/02640414.2023.2180160" }, { "id": "gielen2026-fitbit-charge-6-hr_exercise-mae_bpm", "study_id": "gielen2026", "device": "Fitbit Charge 6", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-charge-6", "metric": "hr_exercise", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 4.5, "value_text": "4.5 bpm", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": "MAPE 5.5%, CCC 0.93", "subgroup": "mixed rest/stress/walking", "reference": "ECG chest strap (Zephyr BioHarness / Faros)", "reference_class": "ecg", "setting": "Rest, cognitive stress, steady and intermittent walking in neutral/hot/cold chambers", "n": 45, "n_note": null, "population": "Healthy adults 21–68 y", "skin_tone": null, "industry_funded": false, "quote": "Fitbit Charge 6 (MAE 4.5 bpm, MAPE 5.5%, CCC 0.93)", "location": "Abstract", "note": null, "doi": "10.2196/85186" }, { "id": "gielen2026-google-pixel-watch-2-hr_exercise-mae_bpm", "study_id": "gielen2026", "device": "Google Pixel Watch 2", "brand": "google", "brand_name": "Google", "device_slug": "google-pixel-watch-2", "metric": "hr_exercise", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 4.9, "value_text": "4.9 bpm", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": "MAPE 6.7%, CCC 0.87", "subgroup": "mixed rest/stress/walking", "reference": "ECG chest strap (Zephyr BioHarness / Faros)", "reference_class": "ecg", "setting": "Rest, cognitive stress, steady and intermittent walking in neutral/hot/cold chambers", "n": 45, "n_note": null, "population": "Healthy adults 21–68 y", "skin_tone": null, "industry_funded": false, "quote": "Google Pixel Watch 2 (MAE 4.9 bpm, MAPE 6.7%, CCC 0.87)", "location": "Abstract", "note": null, "doi": "10.2196/85186" }, { "id": "gielen2026-fitbit-inspire-3-hr_exercise-mae_bpm", "study_id": "gielen2026", "device": "Fitbit Inspire 3", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": null, "metric": "hr_exercise", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": null, "value_text": "9–14 bpm (group range)", "unit": "bpm", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": "mixed rest/stress/walking", "reference": "ECG chest strap (Zephyr BioHarness / Faros)", "reference_class": "ecg", "setting": "Rest, cognitive stress, steady and intermittent walking in neutral/hot/cold chambers", "n": 45, "n_note": null, "population": "Healthy adults 21–68 y", "skin_tone": null, "industry_funded": false, "quote": "Fitbit Inspire 3, Polar Ignite 3, Polar Pacer, and Oura Ring displayed larger errors (MAE 9-14 bpm, MAPE 11%-16%)", "location": "Abstract", "note": null, "doi": "10.2196/85186" }, { "id": "gielen2026-polar-ignite-3-hr_exercise-mae_bpm", "study_id": "gielen2026", "device": "Polar Ignite 3", "brand": "polar", "brand_name": "Polar", "device_slug": null, "metric": "hr_exercise", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": null, "value_text": "9–14 bpm (group range)", "unit": "bpm", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": "mixed rest/stress/walking", "reference": "ECG chest strap (Zephyr BioHarness / Faros)", "reference_class": "ecg", "setting": "Rest, cognitive stress, steady and intermittent walking in neutral/hot/cold chambers", "n": 45, "n_note": null, "population": "Healthy adults 21–68 y", "skin_tone": null, "industry_funded": false, "quote": "Fitbit Inspire 3, Polar Ignite 3, Polar Pacer, and Oura Ring displayed larger errors (MAE 9-14 bpm, MAPE 11%-16%)", "location": "Abstract", "note": null, "doi": "10.2196/85186" }, { "id": "gielen2026-polar-pacer-hr_exercise-mae_bpm", "study_id": "gielen2026", "device": "Polar Pacer", "brand": "polar", "brand_name": "Polar", "device_slug": null, "metric": "hr_exercise", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": null, "value_text": "9–14 bpm (group range)", "unit": "bpm", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": "mixed rest/stress/walking", "reference": "ECG chest strap (Zephyr BioHarness / Faros)", "reference_class": "ecg", "setting": "Rest, cognitive stress, steady and intermittent walking in neutral/hot/cold chambers", "n": 45, "n_note": null, "population": "Healthy adults 21–68 y", "skin_tone": null, "industry_funded": false, "quote": "Fitbit Inspire 3, Polar Ignite 3, Polar Pacer, and Oura Ring displayed larger errors (MAE 9-14 bpm, MAPE 11%-16%)", "location": "Abstract", "note": null, "doi": "10.2196/85186" }, { "id": "gielen2026-oura-ring-gen3-hr_exercise-mae_bpm", "study_id": "gielen2026", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "hr_exercise", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": null, "value_text": "9–14 bpm (group range)", "unit": "bpm", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": "mixed rest/stress/walking", "reference": "ECG chest strap (Zephyr BioHarness / Faros)", "reference_class": "ecg", "setting": "Rest, cognitive stress, steady and intermittent walking in neutral/hot/cold chambers", "n": 45, "n_note": null, "population": "Healthy adults 21–68 y", "skin_tone": null, "industry_funded": false, "quote": "Fitbit Inspire 3, Polar Ignite 3, Polar Pacer, and Oura Ring displayed larger errors (MAE 9-14 bpm, MAPE 11%-16%)", "location": "Abstract", "note": null, "doi": "10.2196/85186" }, { "id": "moghaddam2025-whoop-4-0-upper-arm-hr_exercise-finding", "study_id": "moghaddam2025", "device": "WHOOP 4.0 (upper arm)", "brand": "whoop", "brand_name": "WHOOP", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Strongest agreement (with Verity Sense) in graded treadmill", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Rest, warm-up, burpees, Bruce treadmill", "n": 28, "n_note": null, "population": "Healthy adults 23.8 y, 14 M / 14 F", "skin_tone": null, "industry_funded": false, "quote": "During the Modified Bruce protocol, Verity Sense and Whoop-upper arm had the strongest agreement with the chest strap", "location": "Abstract", "note": null, "doi": "10.3390/s26010176" }, { "id": "moghaddam2025-polar-verity-sense-hr_exercise-finding", "study_id": "moghaddam2025", "device": "Polar Verity Sense", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-verity-sense", "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Strongest agreement (with WHOOP upper arm) in graded treadmill", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Rest, warm-up, burpees, Bruce treadmill", "n": 28, "n_note": null, "population": "Healthy adults 23.8 y, 14 M / 14 F", "skin_tone": null, "industry_funded": false, "quote": "During the Modified Bruce protocol, Verity Sense and Whoop-upper arm had the strongest agreement with the chest strap", "location": "Abstract", "note": null, "doi": "10.3390/s26010176" }, { "id": "ogrady2024-apple-watch-series-9-ultra-2-hrv_rmssd-mape_pct", "study_id": "ogrady2024", "device": "Apple Watch Series 9 / Ultra 2", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-9", "metric": "hrv_rmssd", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 28.88, "value_text": "28.88% (MAE 20.46 ms)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "Bias −8.31 ms; Apple reports SDNN", "subgroup": null, "reference": "Polar H10 + Kubios HRV", "reference_class": "ecg", "setting": "Serial morning measurements over 14 days, 316 readings", "n": 39, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "with a mean absolute percentage error (MAPE) of 28.88% and a mean absolute error (MAE) of 20.46 ms", "location": "Abstract", "note": "Apple Watch reports SDNN, not RMSSD", "doi": "10.3390/s24196220" }, { "id": "ogrady2024-apple-watch-series-9-ultra-2-hr_rest-mape_pct", "study_id": "ogrady2024", "device": "Apple Watch Series 9 / Ultra 2", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-9", "metric": "hr_rest", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 5.91, "value_text": "5.91% (MAE 3.73 bpm)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polar H10 + Kubios HRV", "reference_class": "ecg", "setting": "Serial morning measurements over 14 days, 316 readings", "n": 39, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "an MAPE of 5.91%, and an MAE of 3.73 bpm", "location": "Abstract", "note": null, "doi": "10.3390/s24196220" }, { "id": "bonneval2025-apple-watch-series-6-hr_rest-mape_pct", "study_id": "bonneval2025", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "hr_rest", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 1.15, "value_text": "1.15%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": "R-R intervals and BPM at rest", "reference": "ECG", "reference_class": "ecg", "setting": "Lab: rest, talking, movie, before/after walking", "n": 78, "n_note": null, "population": "Healthy adults 20–75 y", "skin_tone": null, "industry_funded": false, "quote": "mean absolute percentage errors (MAPE) of 1.15% during resting conditions", "location": "Abstract", "note": null, "doi": "10.3390/s25082380" }, { "id": "nissen2022-fitbit-charge-4-hr_rest-mae_bpm", "study_id": "nissen2022", "device": "Fitbit Charge 4", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-charge-4", "metric": "hr_rest", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 7.8, "value_text": "7.8 bpm (seated rest)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Holter ECG", "reference_class": "ecg", "setting": "Rest, sedentary, low- and high-intensity phases", "n": 23, "n_note": null, "population": "Healthy adults 24.2 y", "skin_tone": null, "industry_funded": false, "quote": "seated rest: 7.8 vs 9.4", "location": "Abstract", "note": null, "doi": "10.2196/33635" }, { "id": "nissen2022-samsung-galaxy-watch-active2-hr_rest-mae_bpm", "study_id": "nissen2022", "device": "Samsung Galaxy Watch Active2", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-active-2", "metric": "hr_rest", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 9.4, "value_text": "9.4 bpm (seated rest)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Holter ECG", "reference_class": "ecg", "setting": "Rest, sedentary, low- and high-intensity phases", "n": 23, "n_note": null, "population": "Healthy adults 24.2 y", "skin_tone": null, "industry_funded": false, "quote": "seated rest: 7.8 vs 9.4", "location": "Abstract", "note": null, "doi": "10.2196/33635" }, { "id": "nissen2022-fitbit-charge-4-hr_exercise-mae_bpm", "study_id": "nissen2022", "device": "Fitbit Charge 4", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-charge-4", "metric": "hr_exercise", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 15.7, "value_text": "15.7 bpm (squats)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": "squats", "reference": "Holter ECG", "reference_class": "ecg", "setting": "Rest, sedentary, low- and high-intensity phases", "n": 23, "n_note": null, "population": "Healthy adults 24.2 y", "skin_tone": null, "industry_funded": false, "quote": "squats: 15.7 vs 6.1", "location": "Abstract", "note": null, "doi": "10.2196/33635" }, { "id": "nissen2022-samsung-galaxy-watch-active2-hr_exercise-mae_bpm", "study_id": "nissen2022", "device": "Samsung Galaxy Watch Active2", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-active-2", "metric": "hr_exercise", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 6.1, "value_text": "6.1 bpm (squats)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": "squats", "reference": "Holter ECG", "reference_class": "ecg", "setting": "Rest, sedentary, low- and high-intensity phases", "n": 23, "n_note": null, "population": "Healthy adults 24.2 y", "skin_tone": null, "industry_funded": false, "quote": "squats: 15.7 vs 6.1", "location": "Abstract", "note": null, "doi": "10.2196/33635" }, { "id": "jeong2026-apple-watch-se-hr_exercise-finding", "study_id": "jeong2026", "device": "Apple Watch SE", "brand": "apple", "brand_name": "Apple", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Significantly lower MAE than Polar Pacer Pro and Galaxy Watch 6", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Low/moderate/high-intensity treadmill", "n": 37, "n_note": null, "population": "Healthy young adults", "skin_tone": null, "industry_funded": false, "quote": "The Polar Verity Sense and Apple Watch SE showed significantly lower MAE than the Polar Pacer Pro and Galaxy Watch 6", "location": "Abstract", "note": null, "doi": "10.20463/pan.2026.0032" }, { "id": "jeong2026-polar-verity-sense-hr_exercise-finding", "study_id": "jeong2026", "device": "Polar Verity Sense", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-verity-sense", "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Significantly lower MAE than Polar Pacer Pro and Galaxy Watch 6", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Low/moderate/high-intensity treadmill", "n": 37, "n_note": null, "population": "Healthy young adults", "skin_tone": null, "industry_funded": false, "quote": "The Polar Verity Sense and Apple Watch SE showed significantly lower MAE than the Polar Pacer Pro and Galaxy Watch 6", "location": "Abstract", "note": null, "doi": "10.20463/pan.2026.0032" }, { "id": "jeong2026-polar-pacer-pro-hr_exercise-finding", "study_id": "jeong2026", "device": "Polar Pacer Pro", "brand": "polar", "brand_name": "Polar", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Significantly higher MAE than Apple Watch SE and Verity Sense", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Low/moderate/high-intensity treadmill", "n": 37, "n_note": null, "population": "Healthy young adults", "skin_tone": null, "industry_funded": false, "quote": "The Polar Verity Sense and Apple Watch SE showed significantly lower MAE than the Polar Pacer Pro and Galaxy Watch 6", "location": "Abstract", "note": null, "doi": "10.20463/pan.2026.0032" }, { "id": "jeong2026-samsung-galaxy-watch-6-hr_exercise-finding", "study_id": "jeong2026", "device": "Samsung Galaxy Watch 6", "brand": "samsung", "brand_name": "Samsung", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Significantly higher MAE than Apple Watch SE and Verity Sense", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Low/moderate/high-intensity treadmill", "n": 37, "n_note": null, "population": "Healthy young adults", "skin_tone": null, "industry_funded": false, "quote": "The Polar Verity Sense and Apple Watch SE showed significantly lower MAE than the Polar Pacer Pro and Galaxy Watch 6", "location": "Abstract", "note": null, "doi": "10.20463/pan.2026.0032" }, { "id": "mulholland2026-apple-watch-series-8-hr_exercise-finding", "study_id": "mulholland2026", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Skin pigmentation did not predict error (P = 0.62); 50% of missing data from dark-skin participants", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Rest, cycling, recovery", "n": 28, "n_note": null, "population": "Adults; ITA°-measured skin pigmentation (16 White, 10 Black, 2 other)", "skin_tone": "ITA° colorimetry; 10 Black participants", "industry_funded": false, "quote": "ITA° predicted MAEHR for SlateSafety (β = - 0.011, P = 0.001), but not for Apple (P = 0.62) or Garmin (P = 0.29)", "location": "Abstract", "note": null, "doi": "10.1007/s00421-025-05977-x" }, { "id": "mulholland2026-garmin-vivosmart-5-hr_exercise-finding", "study_id": "mulholland2026", "device": "Garmin Vivosmart 5", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Skin pigmentation did not predict error (P = 0.29)", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Rest, cycling, recovery", "n": 28, "n_note": null, "population": "Adults; ITA°-measured skin pigmentation (16 White, 10 Black, 2 other)", "skin_tone": "ITA° colorimetry; 10 Black participants", "industry_funded": false, "quote": "ITA° predicted MAEHR for SlateSafety (β = - 0.011, P = 0.001), but not for Apple (P = 0.62) or Garmin (P = 0.29)", "location": "Abstract", "note": null, "doi": "10.1007/s00421-025-05977-x" }, { "id": "chase2024-apple-watch-series-9-hr_exercise-finding", "study_id": "chase2024", "device": "Apple Watch Series 9", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-9", "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Less accurate for darker skin pigmentation", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "10-min treadmill", "n": 30, "n_note": null, "population": "Young adults in 3 Fitzpatrick groups", "skin_tone": "Fitzpatrick groups", "industry_funded": false, "quote": "for HR, the Apple Watch Series 9 was more variable (i.e., less accurate) for darker skin pigmentations compared to lighter skin pigmentations", "location": "Abstract", "note": null, "doi": "10.3390/jfmk9040275" }, { "id": "chase2024-apple-watch-series-9-energy-finding", "study_id": "chase2024", "device": "Apple Watch Series 9", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-9", "metric": "energy", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Inconsistent across all groups", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "10-min treadmill", "n": 30, "n_note": null, "population": "Young adults in 3 Fitzpatrick groups", "skin_tone": null, "industry_funded": false, "quote": "Overall, EE was found to be inconsistent for all skin pigmentation groups", "location": "Abstract", "note": null, "doi": "10.3390/jfmk9040275" }, { "id": "duking2020-apple-watch-series-4-hr_exercise-cv_pct", "study_id": "duking2020", "device": "Apple Watch Series 4", "brand": "apple", "brand_name": "Apple", "device_slug": null, "metric": "hr_exercise", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "0.9%–4.3% (range by intensity)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Sitting, walking, running, sprints", "n": 25, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "the corresponding coefficients of variation were 0.9%-4.3%, 2.2%-6.7%, 2.9%-9.2%, and 4.1%-19.1%, respectively", "location": "Abstract", "note": null, "doi": "10.2196/16716" }, { "id": "duking2020-polar-vantage-v-hr_exercise-cv_pct", "study_id": "duking2020", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "hr_exercise", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "2.2%–6.7% (range by intensity)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Sitting, walking, running, sprints", "n": 25, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "the corresponding coefficients of variation were 0.9%-4.3%, 2.2%-6.7%, 2.9%-9.2%, and 4.1%-19.1%, respectively", "location": "Abstract", "note": null, "doi": "10.2196/16716" }, { "id": "duking2020-garmin-fenix-5-hr_exercise-cv_pct", "study_id": "duking2020", "device": "Garmin Fenix 5", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "hr_exercise", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "2.9%–9.2% (range by intensity)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Sitting, walking, running, sprints", "n": 25, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "the corresponding coefficients of variation were 0.9%-4.3%, 2.2%-6.7%, 2.9%-9.2%, and 4.1%-19.1%, respectively", "location": "Abstract", "note": null, "doi": "10.2196/16716" }, { "id": "duking2020-fitbit-versa-hr_exercise-cv_pct", "study_id": "duking2020", "device": "Fitbit Versa", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": null, "metric": "hr_exercise", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "4.1%–19.1% (range by intensity)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Sitting, walking, running, sprints", "n": 25, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "the corresponding coefficients of variation were 0.9%-4.3%, 2.2%-6.7%, 2.9%-9.2%, and 4.1%-19.1%, respectively", "location": "Abstract", "note": null, "doi": "10.2196/16716" }, { "id": "duking2020-apple-watch-series-4-energy-cv_pct", "study_id": "duking2020", "device": "Apple Watch Series 4", "brand": "apple", "brand_name": "Apple", "device_slug": null, "metric": "energy", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "13.5%–27.1% (range by intensity)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Sitting, walking, running, sprints", "n": 25, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "coefficients of variation were 13.5%-27.1%, 16.3%-28.0%, 15.9%-34.5%, and 8.0%-32.3%, respectively", "location": "Abstract", "note": null, "doi": "10.2196/16716" }, { "id": "duking2020-polar-vantage-v-energy-cv_pct", "study_id": "duking2020", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "energy", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "16.3%–28.0% (range by intensity)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Sitting, walking, running, sprints", "n": 25, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "coefficients of variation were 13.5%-27.1%, 16.3%-28.0%, 15.9%-34.5%, and 8.0%-32.3%, respectively", "location": "Abstract", "note": null, "doi": "10.2196/16716" }, { "id": "duking2020-garmin-fenix-5-energy-cv_pct", "study_id": "duking2020", "device": "Garmin Fenix 5", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "energy", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "15.9%–34.5% (range by intensity)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Sitting, walking, running, sprints", "n": 25, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "coefficients of variation were 13.5%-27.1%, 16.3%-28.0%, 15.9%-34.5%, and 8.0%-32.3%, respectively", "location": "Abstract", "note": null, "doi": "10.2196/16716" }, { "id": "duking2020-fitbit-versa-energy-cv_pct", "study_id": "duking2020", "device": "Fitbit Versa", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": null, "metric": "energy", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "8.0%–32.3% (range by intensity)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Sitting, walking, running, sprints", "n": 25, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "coefficients of variation were 13.5%-27.1%, 16.3%-28.0%, 15.9%-34.5%, and 8.0%-32.3%, respectively", "location": "Abstract", "note": null, "doi": "10.2196/16716" }, { "id": "hajjboutros2023-apple-watch-series-6-hr_exercise-cv_pct", "study_id": "hajjboutros2023", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "hr_exercise", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "< 5% in all 5 activities", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Sitting, walking, running, resistance, cycling", "n": 60, "n_note": null, "population": "Healthy young adults, 30 M / 30 W", "skin_tone": null, "industry_funded": false, "quote": "The Apple Watch 6 displayed the highest level of accuracy for heart rate measurement with a coefficient of variation (CV) (%) of less than 5% for all 5 activities", "location": "Abstract", "note": null, "doi": "10.1080/17461391.2021.2023656" }, { "id": "hajjboutros2023-polar-vantage-v-hr_exercise-cv_pct", "study_id": "hajjboutros2023", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "hr_exercise", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "2.44–8.80%", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Sitting, walking, running, resistance, cycling", "n": 60, "n_note": null, "population": "Healthy young adults, 30 M / 30 W", "skin_tone": null, "industry_funded": false, "quote": "CVs between 2.44-8.80% and 4.14-10.76%, respectively", "location": "Abstract", "note": null, "doi": "10.1080/17461391.2021.2023656" }, { "id": "hajjboutros2023-fitbit-sense-hr_exercise-cv_pct", "study_id": "hajjboutros2023", "device": "Fitbit Sense", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense", "metric": "hr_exercise", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "4.14–10.76%", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Sitting, walking, running, resistance, cycling", "n": 60, "n_note": null, "population": "Healthy young adults, 30 M / 30 W", "skin_tone": null, "industry_funded": false, "quote": "CVs between 2.44-8.80% and 4.14-10.76%, respectively", "location": "Abstract", "note": null, "doi": "10.1080/17461391.2021.2023656" }, { "id": "hajjboutros2023-apple-watch-series-6-energy-cv_pct", "study_id": "hajjboutros2023", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "energy", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "14.68–24.85% (poor in all activities)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Sitting, walking, running, resistance, cycling", "n": 60, "n_note": null, "population": "Healthy young adults", "skin_tone": null, "industry_funded": false, "quote": "14.68-24.85%", "location": "Abstract", "note": null, "doi": "10.1080/17461391.2021.2023656" }, { "id": "hajjboutros2023-polar-vantage-v-energy-cv_pct", "study_id": "hajjboutros2023", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "energy", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "16.54–25.78% (poor in all activities)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Sitting, walking, running, resistance, cycling", "n": 60, "n_note": null, "population": "Healthy young adults", "skin_tone": null, "industry_funded": false, "quote": "16.54-25.78%", "location": "Abstract", "note": null, "doi": "10.1080/17461391.2021.2023656" }, { "id": "hajjboutros2023-fitbit-sense-energy-cv_pct", "study_id": "hajjboutros2023", "device": "Fitbit Sense", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense", "metric": "energy", "statistic": "cv_pct", "statistic_label": "Coefficient of variation", "value": null, "value_text": "13.44–29.66% (poor in all activities)", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Sitting, walking, running, resistance, cycling", "n": 60, "n_note": null, "population": "Healthy young adults", "skin_tone": null, "industry_funded": false, "quote": "13.44-29.66%", "location": "Abstract", "note": null, "doi": "10.1080/17461391.2021.2023656" }, { "id": "stve2023-apple-watch-series-7-spo2-rmse_pct", "study_id": "stve2023", "device": "Apple Watch Series 7", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-7", "metric": "spo2", "statistic": "rmse_pct", "statistic_label": "Root-mean-square error", "value": 3.5, "value_text": "3.5% (rest)", "unit": "% points", "higher_is_better": false, "rankable": true, "secondary": "4.1% after sit-to-stand", "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Rest, COPD outpatients", "n": 36, "n_note": null, "population": "People with COPD, 52–89 y, 20 women", "skin_tone": null, "industry_funded": false, "quote": "For the Apple Watch, the root mean squared error showed a deviation of 3.5% at rest", "location": "Abstract", "note": null, "doi": "10.4187/respcare.10760" }, { "id": "stve2023-garmin-vivosmart-4-spo2-rmse_pct", "study_id": "stve2023", "device": "Garmin Vivosmart 4", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-vivosmart-4", "metric": "spo2", "statistic": "rmse_pct", "statistic_label": "Root-mean-square error", "value": 3.3, "value_text": "3.3% (rest)", "unit": "% points", "higher_is_better": false, "rankable": true, "secondary": "6.1% after sit-to-stand", "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Rest, COPD outpatients", "n": 36, "n_note": null, "population": "People with COPD, 52–89 y, 20 women", "skin_tone": null, "industry_funded": false, "quote": "For the Garmin Vivosmart, the root mean squared error showed a deviation of 3.3% at rest", "location": "Abstract", "note": null, "doi": "10.4187/respcare.10760" }, { "id": "spaccarotella2022-apple-watch-series-6-spo2-r", "study_id": "spaccarotella2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "spo2", "statistic": "r", "statistic_label": "Pearson correlation", "value": 0.89, "value_text": "r = 0.89", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "Bias −0.23; LoA −3.49 to 3.04", "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Spot readings", "n": 265, "n_note": null, "population": "Healthy, lung disease and cardiovascular disease (265 screened)", "skin_tone": null, "industry_funded": false, "quote": "(r = 0.89, p < 0.0001)", "location": "Abstract", "note": null, "doi": "10.3390/jcm11061467" }, { "id": "spaccarotella2022-apple-watch-series-6-spo2-bias", "study_id": "spaccarotella2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "spo2", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -0.2289, "value_text": "−0.23 (LoA −3.49 to 3.04)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Spot readings", "n": 265, "n_note": null, "population": "Healthy, lung disease and cardiovascular disease (265 screened)", "skin_tone": null, "industry_funded": false, "quote": "SpO2 (bias, −0.2289; SD, 1.66; lower limit, −3.49; and upper limit, 3.04)", "location": "Abstract", "note": null, "doi": "10.3390/jcm11061467" }, { "id": "jiang2023-apple-watch-series-7-spo2-mae_pct", "study_id": "jiang2023", "device": "Apple Watch Series 7", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-7", "metric": "spo2", "statistic": "mae_pct", "statistic_label": "Mean absolute error", "value": 2.2, "value_text": "2.2% (RMSE 2.9%)", "unit": "% points", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Spot readings, with and without chronic pulmonary disease", "n": 49, "n_note": null, "population": "Adults 18–85 y, 18 F", "skin_tone": "Fitzpatrick and ITA measured; MAE did not vary by skin tone group", "industry_funded": false, "quote": "Apple Watch Series 7 having measurements closest to the reference standard (MAE = 2.2%, MDE = -0.4%, RMSE = 2.9%)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pdig.0000296" }, { "id": "jiang2023-apple-watch-series-7-spo2-rmse_pct", "study_id": "jiang2023", "device": "Apple Watch Series 7", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-7", "metric": "spo2", "statistic": "rmse_pct", "statistic_label": "Root-mean-square error", "value": 2.9, "value_text": "2.9%", "unit": "% points", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Spot readings, with and without chronic pulmonary disease", "n": 49, "n_note": null, "population": "Adults 18–85 y, 18 F", "skin_tone": "Fitzpatrick and ITA measured; MAE did not vary by skin tone group", "industry_funded": false, "quote": "Apple Watch Series 7 having measurements closest to the reference standard (MAE = 2.2%, MDE = -0.4%, RMSE = 2.9%)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pdig.0000296" }, { "id": "jiang2023-garmin-venu-2s-spo2-mae_pct", "study_id": "jiang2023", "device": "Garmin Venu 2S", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "spo2", "statistic": "mae_pct", "statistic_label": "Mean absolute error", "value": 5.8, "value_text": "5.8% (RMSE 6.7%)", "unit": "% points", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Spot readings, with and without chronic pulmonary disease", "n": 49, "n_note": null, "population": "Adults 18–85 y, 18 F", "skin_tone": "Fitzpatrick and ITA measured; MAE did not vary by skin tone group", "industry_funded": false, "quote": "the Garmin Venu 2s having measurements farthest from the reference standard (MAE = 5.8%, MDE = 5.5%, RMSE = 6.7%)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pdig.0000296" }, { "id": "jiang2023-garmin-venu-2s-spo2-rmse_pct", "study_id": "jiang2023", "device": "Garmin Venu 2S", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "spo2", "statistic": "rmse_pct", "statistic_label": "Root-mean-square error", "value": 6.7, "value_text": "6.7%", "unit": "% points", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Spot readings, with and without chronic pulmonary disease", "n": 49, "n_note": null, "population": "Adults 18–85 y, 18 F", "skin_tone": "Fitzpatrick and ITA measured; MAE did not vary by skin tone group", "industry_funded": false, "quote": "the Garmin Venu 2s having measurements farthest from the reference standard (MAE = 5.8%, MDE = 5.5%, RMSE = 6.7%)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pdig.0000296" }, { "id": "jiang2023-withings-scanwatch-spo2-finding", "study_id": "jiang2023", "device": "Withings ScanWatch", "brand": "withings", "brand_name": "Withings", "device_slug": "withings-scanwatch", "metric": "spo2", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Highest missingness: 69.5% of attempts successful", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Spot readings, with and without chronic pulmonary disease", "n": 49, "n_note": null, "population": "Adults 18–85 y, 18 F", "skin_tone": "Fitzpatrick and ITA measured; MAE did not vary by skin tone group", "industry_funded": false, "quote": "the highest data missingness from the Withings ScanWatch (only 69.5% of attempted measurements were successful)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pdig.0000296" }, { "id": "walzel2023-apple-watch-series-8-spo2-finding", "study_id": "walzel2023", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "spo2", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Met ISO RMS ≤ 4% at normoxia and SpO2 < 90%; lowest bias and RMSD of the three", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Induced hypoxemia (FiO2 14%, 12%, 10%), ISO 80601-2-61", "n": 18, "n_note": null, "population": "Young healthy adults", "skin_tone": null, "industry_funded": false, "quote": "All three smartwatch models met the maximum acceptable root-mean-square deviation (≤4%) from the reference measurement at both normal oxygen levels and induced desaturation with SpO2 less than 90%", "location": "Abstract", "note": null, "doi": "10.3390/s23229164" }, { "id": "walzel2023-samsung-galaxy-watch5-spo2-finding", "study_id": "walzel2023", "device": "Samsung Galaxy Watch5", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-5", "metric": "spo2", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Met ISO RMS ≤ 4% at normoxia and SpO2 < 90%", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Induced hypoxemia (FiO2 14%, 12%, 10%), ISO 80601-2-61", "n": 18, "n_note": null, "population": "Young healthy adults", "skin_tone": null, "industry_funded": false, "quote": "All three smartwatch models met the maximum acceptable root-mean-square deviation (≤4%) from the reference measurement at both normal oxygen levels and induced desaturation with SpO2 less than 90%", "location": "Abstract", "note": null, "doi": "10.3390/s23229164" }, { "id": "walzel2023-withings-scanwatch-spo2-finding", "study_id": "walzel2023", "device": "Withings ScanWatch", "brand": "withings", "brand_name": "Withings", "device_slug": "withings-scanwatch", "metric": "spo2", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Met ISO RMS ≤ 4% at normoxia and SpO2 < 90%", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Induced hypoxemia (FiO2 14%, 12%, 10%), ISO 80601-2-61", "n": 18, "n_note": null, "population": "Young healthy adults", "skin_tone": null, "industry_funded": false, "quote": "All three smartwatch models met the maximum acceptable root-mean-square deviation (≤4%) from the reference measurement at both normal oxygen levels and induced desaturation with SpO2 less than 90%", "location": "Abstract", "note": null, "doi": "10.3390/s23229164" }, { "id": "jiang2026-apple-watch-series-7-spo2-rmse_pct", "study_id": "jiang2026", "device": "Apple Watch Series 7", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-7", "metric": "spo2", "statistic": "rmse_pct", "statistic_label": "Root-mean-square error", "value": 5.82, "value_text": "Arms 5.82% (SaO2 < 88%)", "unit": "% points", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": "SaO2 < 88%", "reference": "Arterial blood gas (SaO2)", "reference_class": "arterial_blood_gas", "setting": "Controlled hypoxia, SaO2 < 88% subset", "n": null, "n_note": null, "population": "See full text", "skin_tone": null, "industry_funded": false, "quote": "5.82% (95% CI 5.32%-6.31%) for the Masimo MightySat Rx and Apple Watch Series 7, respectively", "location": "Abstract", "note": null, "doi": "10.2196/85253" }, { "id": "browne2025-samsung-galaxy-watch4-spo2-rmse_pct", "study_id": "browne2025", "device": "Samsung Galaxy Watch4", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-4", "metric": "spo2", "statistic": "rmse_pct", "statistic_label": "Root-mean-square error", "value": 1.8, "value_text": "RMSD 1.8%", "unit": "% points", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Arterial blood gas (SaO2)", "reference_class": "arterial_blood_gas", "setting": "Hypoxia lab, SaO2 plateaus 70–100%, FDA/ISO procedure", "n": 24, "n_note": null, "population": "Healthy adults 21–46 y; 25% Fitzpatrick V–VI", "skin_tone": "Fitzpatrick I–II 20.8%, III–IV 54%, V–VI 25%", "industry_funded": false, "quote": "smartwatch 1.8% (247 data pairs)", "location": "Abstract", "note": null, "doi": "10.3390/s25051286" }, { "id": "patz2023-apple-watch-series-6-spo2-finding", "study_id": "patz2023", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "spo2", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Not yet up to the medical standard of pulse oximetry", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Congenital heart disease clinic", "n": 508, "n_note": null, "population": "Children and adults with congenital heart disease", "skin_tone": null, "industry_funded": false, "quote": "oxygen saturation measurement with the Apple Watch 6 is not yet up to the medical standard of pulse oximetry", "location": "Abstract", "note": null, "doi": "10.1007/s00246-022-02987-w" }, { "id": "arslan2024-apple-watch-series-6-spo2-bias", "study_id": "arslan2024", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "spo2", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": 0.458, "value_text": "0.46% vs ABG (LoA −5.91 to 5.00)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Arterial blood gas (SaO2)", "reference_class": "arterial_blood_gas", "setting": "Emergency department, COPD exacerbation", "n": 167, "n_note": null, "population": "Emergency patients", "skin_tone": null, "industry_funded": false, "quote": "a mean error of 0.458% between the Apple Watch 6 and ABG (SD: 2.78, level of agreement: - 5.912 to 4.996)", "location": "Abstract", "note": null, "doi": "10.1007/s11845-023-03456-w" }, { "id": "rajakariar2024-apple-watch-series-7-spo2-sensitivity_pct", "study_id": "rajakariar2024", "device": "Apple Watch Series 7", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-7", "metric": "spo2", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 34.8, "value_text": "34.8% (spec 97.5%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": "specificity 97.5%", "subgroup": "detecting clinically significant hypoxia", "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Hospital ward, COVID-19 inpatients", "n": 200, "n_note": null, "population": "Hospitalised COVID-19 patients, 66 ± 18 y", "skin_tone": null, "industry_funded": false, "quote": "the Apple Watch had a sensitivity and specificity of 34.8% and 97.5%", "location": "Abstract", "note": null, "doi": "10.1016/j.mcpdig.2024.02.001" }, { "id": "rajakariar2024-withings-scanwatch-spo2-sensitivity_pct", "study_id": "rajakariar2024", "device": "Withings ScanWatch", "brand": "withings", "brand_name": "Withings", "device_slug": "withings-scanwatch", "metric": "spo2", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 68.5, "value_text": "68.5% (spec 80.8%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": "specificity 80.8%", "subgroup": "detecting clinically significant hypoxia", "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Hospital ward, COVID-19 inpatients", "n": 200, "n_note": null, "population": "Hospitalised COVID-19 patients, 66 ± 18 y", "skin_tone": null, "industry_funded": false, "quote": "The Withings ScanWatch had a sensitivity and specificity of 68.5% and 80.8%", "location": "Abstract", "note": null, "doi": "10.1016/j.mcpdig.2024.02.001" }, { "id": "schiefer2021-garmin-fenix-5x-plus-spo2-mape_pct", "study_id": "schiefer2021", "device": "Garmin Fenix 5X Plus", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "spo2", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 9.77, "value_text": "9.77% (ICC 0.549)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Arterial blood gas (SaO2)", "reference_class": "arterial_blood_gas", "setting": "High altitude 4559 m", "n": 13, "n_note": null, "population": "Healthy lowlanders", "skin_tone": null, "industry_funded": false, "quote": "Validity of GAR was low, as indicated by the ICC (0.549), the MAPE (9.77%)", "location": "Abstract", "note": null, "doi": "10.3390/s21196363" }, { "id": "lauterbach2021-garmin-fenix-5x-plus-spo2-bias", "study_id": "lauterbach2021", "device": "Garmin Fenix 5X Plus", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "spo2", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": 3.3, "value_text": "+3.3% at 12,000 ft (LoA −1.9 to 8.6%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Normobaric hypoxia, rest, 900–12,000 ft", "n": 23, "n_note": null, "population": "Young adults, 13 W / 10 M", "skin_tone": null, "industry_funded": false, "quote": "Bland-Altman analysis indicated 3.3% bias for SpO2 measurements taken on the Garmin fēnix® at 12,000 ft of simulated altitude", "location": "Abstract", "note": null, "doi": "10.1080/02701367.2020.1759768" }, { "id": "mannhart2023-apple-watch-series-6-af-sensitivity_pct", "study_id": "mannhart2023", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "af", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 85, "value_text": "85% (spec 75%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": "specificity 75%", "subgroup": "smartwatch ECG app, inconclusive tracings counted", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Tertiary cardiology service, single-lead ECG algorithms", "n": 201, "n_note": null, "population": "Cardiology patients, median age 66.7 y, 31% women; AF in 31%", "skin_tone": null, "industry_funded": false, "quote": "85% and 75% for the Apple Watch 6", "location": "Abstract", "note": null, "doi": "10.1016/j.jacep.2022.09.011" }, { "id": "mannhart2023-apple-watch-series-6-af-specificity_pct", "study_id": "mannhart2023", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "af", "statistic": "specificity_pct", "statistic_label": "Specificity", "value": 75, "value_text": "75%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "smartwatch ECG app, inconclusive tracings counted", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Tertiary cardiology service, single-lead ECG algorithms", "n": 201, "n_note": null, "population": "Cardiology patients, median age 66.7 y, 31% women; AF in 31%", "skin_tone": null, "industry_funded": false, "quote": "85% and 75% for the Apple Watch 6", "location": "Abstract", "note": null, "doi": "10.1016/j.jacep.2022.09.011" }, { "id": "mannhart2023-samsung-galaxy-watch3-af-sensitivity_pct", "study_id": "mannhart2023", "device": "Samsung Galaxy Watch3", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-gear-s3-galaxy-watch-3", "metric": "af", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 85, "value_text": "85% (spec 75%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": "specificity 75%", "subgroup": "smartwatch ECG app, inconclusive tracings counted", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Tertiary cardiology service, single-lead ECG algorithms", "n": 201, "n_note": null, "population": "Cardiology patients, median age 66.7 y, 31% women; AF in 31%", "skin_tone": null, "industry_funded": false, "quote": "85% and 75% for the Samsung Galaxy Watch 3", "location": "Abstract", "note": null, "doi": "10.1016/j.jacep.2022.09.011" }, { "id": "mannhart2023-samsung-galaxy-watch3-af-specificity_pct", "study_id": "mannhart2023", "device": "Samsung Galaxy Watch3", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-gear-s3-galaxy-watch-3", "metric": "af", "statistic": "specificity_pct", "statistic_label": "Specificity", "value": 75, "value_text": "75%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "smartwatch ECG app, inconclusive tracings counted", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Tertiary cardiology service, single-lead ECG algorithms", "n": 201, "n_note": null, "population": "Cardiology patients, median age 66.7 y, 31% women; AF in 31%", "skin_tone": null, "industry_funded": false, "quote": "85% and 75% for the Samsung Galaxy Watch 3", "location": "Abstract", "note": null, "doi": "10.1016/j.jacep.2022.09.011" }, { "id": "mannhart2023-withings-scanwatch-af-sensitivity_pct", "study_id": "mannhart2023", "device": "Withings ScanWatch", "brand": "withings", "brand_name": "Withings", "device_slug": "withings-scanwatch", "metric": "af", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 58, "value_text": "58% (spec 75%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": "specificity 75%", "subgroup": "smartwatch ECG app, inconclusive tracings counted", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Tertiary cardiology service, single-lead ECG algorithms", "n": 201, "n_note": null, "population": "Cardiology patients, median age 66.7 y, 31% women; AF in 31%", "skin_tone": null, "industry_funded": false, "quote": "58% and 75% for the Withings Scanwatch", "location": "Abstract", "note": null, "doi": "10.1016/j.jacep.2022.09.011" }, { "id": "mannhart2023-withings-scanwatch-af-specificity_pct", "study_id": "mannhart2023", "device": "Withings ScanWatch", "brand": "withings", "brand_name": "Withings", "device_slug": "withings-scanwatch", "metric": "af", "statistic": "specificity_pct", "statistic_label": "Specificity", "value": 75, "value_text": "75%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "smartwatch ECG app, inconclusive tracings counted", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Tertiary cardiology service, single-lead ECG algorithms", "n": 201, "n_note": null, "population": "Cardiology patients, median age 66.7 y, 31% women; AF in 31%", "skin_tone": null, "industry_funded": false, "quote": "58% and 75% for the Withings Scanwatch", "location": "Abstract", "note": null, "doi": "10.1016/j.jacep.2022.09.011" }, { "id": "mannhart2023-fitbit-sense-af-sensitivity_pct", "study_id": "mannhart2023", "device": "Fitbit Sense", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense", "metric": "af", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 66, "value_text": "66% (spec 79%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": "specificity 79%", "subgroup": "smartwatch ECG app, inconclusive tracings counted", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Tertiary cardiology service, single-lead ECG algorithms", "n": 201, "n_note": null, "population": "Cardiology patients, median age 66.7 y, 31% women; AF in 31%", "skin_tone": null, "industry_funded": false, "quote": "66% and 79% for the Fitbit Sense", "location": "Abstract", "note": null, "doi": "10.1016/j.jacep.2022.09.011" }, { "id": "mannhart2023-fitbit-sense-af-specificity_pct", "study_id": "mannhart2023", "device": "Fitbit Sense", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense", "metric": "af", "statistic": "specificity_pct", "statistic_label": "Specificity", "value": 79, "value_text": "79%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "smartwatch ECG app, inconclusive tracings counted", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Tertiary cardiology service, single-lead ECG algorithms", "n": 201, "n_note": null, "population": "Cardiology patients, median age 66.7 y, 31% women; AF in 31%", "skin_tone": null, "industry_funded": false, "quote": "66% and 79% for the Fitbit Sense", "location": "Abstract", "note": null, "doi": "10.1016/j.jacep.2022.09.011" }, { "id": "wasserlauf2019-apple-watch-kardiaband-smartrhythm-2-0-af-sensitivity_pct", "study_id": "wasserlauf2019", "device": "Apple Watch + KardiaBand (SmartRhythm 2.0)", "brand": "apple", "brand_name": "Apple", "device_slug": null, "metric": "af", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 97.5, "value_text": "97.5% episode sensitivity (PPV 39.9%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": "PPV 39.9%", "subgroup": "AF episodes ≥ 1 h", "reference": "Insertable cardiac monitor", "reference_class": "icm", "setting": "Ambulatory, 31,348.9 h of recordings", "n": 24, "n_note": null, "population": "Patients with paroxysmal AF and insertable cardiac monitors", "skin_tone": null, "industry_funded": false, "quote": "detected 80 episodes (episode sensitivity, 97.5%)", "location": "Abstract", "note": null, "doi": "10.1161/CIRCEP.118.006834" }, { "id": "lambe2026-apple-watch-series-10-vo2max-mape_pct", "study_id": "lambe2026", "device": "Apple Watch Series 10", "brand": "apple", "brand_name": "Apple", "device_slug": null, "metric": "vo2max", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 13.2, "value_text": "13.2% (MAE 6.79 mL/kg/min)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "Bias −6.25 mL/kg/min", "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Maximal treadmill test (modified Åstrand)", "n": 40, "n_note": null, "population": "Healthy adults, 20 women", "skin_tone": null, "industry_funded": false, "quote": "the mean absolute percentage error was 13.2% (95% CI, 9.6-16.8)", "location": "Abstract", "note": null, "doi": "10.1016/j.mcpdig.2026.100357" }, { "id": "lambe2025-apple-watch-vo2max-mape_pct", "study_id": "lambe2025", "device": "Apple Watch", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch", "metric": "vo2max", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 13.31, "value_text": "13.31% (MAE 6.92 mL/kg/min)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "Underestimated by 6.07 mL/kg/min", "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Maximal treadmill test (modified Åstrand)", "n": 30, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "MAPE was calculated as 13.31% (95% CI 10.01-16.61)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pone.0323741" }, { "id": "caserman2024-apple-watch-series-7-vo2max-mape_pct", "study_id": "caserman2024", "device": "Apple Watch Series 7", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-7", "metric": "vo2max", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 15.79, "value_text": "15.79% (ICC 0.47)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "ICC 0.47", "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Graded cycle ergometer test", "n": 19, "n_note": null, "population": "Adults 18–63 y, 7 F / 12 M", "skin_tone": null, "industry_funded": false, "quote": "The mean absolute percentage error between the predicted and the actual VO2max was 15.79%", "location": "Abstract", "note": null, "doi": "10.2196/59459" }, { "id": "engel2026-garmin-forerunner-245-vo2max-mape_pct", "study_id": "engel2026", "device": "Garmin Forerunner 245", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-forerunner-245", "metric": "vo2max", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 7.9, "value_text": "7.9% / 7.2% (two runs)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "ICC 0.71–0.75", "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Treadmill ramp test", "n": 35, "n_note": null, "population": "Trained endurance athletes, 24 M / 11 F", "skin_tone": null, "industry_funded": false, "quote": "with mean absolute percentage errors (MAPE) of 7.9% and 7.2%", "location": "Abstract", "note": null, "doi": "10.1007/s00421-025-05923-x" }, { "id": "carrier2025-garmin-fenix-6-vo2max-mape_pct", "study_id": "carrier2025", "device": "Garmin Fenix 6", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-fenix-6", "metric": "vo2max", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 7.05, "value_text": "7.05% (CCC 0.73)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.73", "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Graded exercise test and outdoor run", "n": 19, "n_note": null, "population": "Healthy active and sedentary adults", "skin_tone": null, "industry_funded": false, "quote": "MAPE for 30 s avg = 7.05%", "location": "Abstract", "note": null, "doi": "10.3390/s25010275" }, { "id": "carrier2025-garmin-fenix-6-spo2-mape_pct", "study_id": "carrier2025", "device": "Garmin Fenix 6", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-fenix-6", "metric": "spo2", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 4.29, "value_text": "4.29% (CCC 0.10)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "CCC 0.10; failed validation criteria", "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "Normoxic and hypoxic conditions", "n": 22, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "MAPE for combined conditions BOS = 4.29%", "location": "Abstract", "note": null, "doi": "10.3390/s25010275" }, { "id": "passler2019-garmin-forerunner-920xt-vo2max-mape_pct", "study_id": "passler2019", "device": "Garmin Forerunner 920XT", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "vo2max", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 7.3, "value_text": "7.3%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Lab", "n": 24, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "except for the VO2max-estimation of the Garmin Forerunner 920XT (7.3%)", "location": "Abstract", "note": null, "doi": "10.3390/ijerph16173037" }, { "id": "lambe2026b-google-pixel-watch-3-vo2max-mape_pct", "study_id": "lambe2026b", "device": "Google Pixel Watch 3", "brand": "google", "brand_name": "Google", "device_slug": null, "metric": "vo2max", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 8.65, "value_text": "8.65% (bias −0.53 mL/kg/min)", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": "LoA −12.56 to 11.50", "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Free-living VO2max estimate vs maximal treadmill test", "n": 34, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": true, "quote": "mean absolute percentage error [MAPE] 8.65%", "location": "Abstract", "note": null, "doi": "10.1371/journal.pone.0356808" }, { "id": "lambe2026b-google-pixel-watch-3-hr_exercise-mape_pct", "study_id": "lambe2026b", "device": "Google Pixel Watch 3", "brand": "google", "brand_name": "Google", "device_slug": null, "metric": "hr_exercise", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 2.73, "value_text": "2.73%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Maximal treadmill test", "n": 34, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": true, "quote": "bias -2.39 bpm; LoA -24.42 to 19.65; MAPE 2.73%", "location": "Abstract", "note": null, "doi": "10.1371/journal.pone.0356808" }, { "id": "lambe2026b-google-pixel-watch-3-energy-mape_pct", "study_id": "lambe2026b", "device": "Google Pixel Watch 3", "brand": "google", "brand_name": "Google", "device_slug": null, "metric": "energy", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 15.02, "value_text": "15.02%", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Maximal treadmill test", "n": 34, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": true, "quote": "bias -8.43 kcal; LoA -72.75 to 55.88; MAPE 15.02%", "location": "Abstract", "note": null, "doi": "10.1371/journal.pone.0356808" }, { "id": "miller2022-apple-watch-series-6-sleep_wake-agreement_pct", "study_id": "miller2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "sleep_wake", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 88, "value_text": "88%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": "κ 0.30", "subgroup": null, "reference": 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"skin_tone": null, "industry_funded": false, "quote": "88% (κ = 0.30) for Apple Watch", "location": "Abstract", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-apple-watch-series-6-sleep_stages-agreement_pct", "study_id": "miller2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 53, "value_text": "53%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": "κ 0.20", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night, 9 h in bed, all devices worn together", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y, 26 F / 27 M", "skin_tone": null, "industry_funded": false, "quote": "53% (κ = 0.20) for Apple Watch", "location": "Abstract", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-apple-watch-series-6-sleep_stages-kappa", "study_id": "miller2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.2, "value_text": "κ = 0.20", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night, 9 h in bed, all devices worn together", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y, 26 F / 27 M", "skin_tone": null, "industry_funded": false, "quote": "53% (κ = 0.20) for Apple Watch", "location": "Abstract", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-garmin-forerunner-245-music-sleep_wake-agreement_pct", "study_id": "miller2022", "device": "Garmin Forerunner 245 Music", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-forerunner-245", "metric": "sleep_wake", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 89, "value_text": "89%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": "κ 0.35", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night, 9 h in bed, all devices worn together", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y, 26 F / 27 M", "skin_tone": null, "industry_funded": false, "quote": "89% (κ = 0.35) for Garmin", "location": "Abstract", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-garmin-forerunner-245-music-sleep_wake-kappa", "study_id": "miller2022", "device": "Garmin Forerunner 245 Music", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-forerunner-245", "metric": "sleep_wake", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.35, "value_text": "κ = 0.35", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night, 9 h in bed, all devices worn together", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y, 26 F / 27 M", "skin_tone": null, "industry_funded": false, "quote": "89% (κ = 0.35) for Garmin", "location": "Abstract", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-garmin-forerunner-245-music-sleep_stages-agreement_pct", "study_id": "miller2022", "device": "Garmin Forerunner 245 Music", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-forerunner-245", "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 50, "value_text": "50%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": "κ 0.25", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep 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"quote": "50% (κ = 0.25) for Garmin", "location": "Abstract", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-polar-vantage-v-sleep_wake-agreement_pct", "study_id": "miller2022", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "sleep_wake", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 87, "value_text": "87%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": "κ 0.44", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night, 9 h in bed, all devices worn together", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y, 26 F / 27 M", "skin_tone": null, "industry_funded": false, "quote": "87% (κ = 0.44) for Polar", "location": "Abstract", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-polar-vantage-v-sleep_wake-kappa", "study_id": "miller2022", "device": "Polar 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"51%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": "κ 0.28", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night, 9 h in bed, all devices worn together", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y, 26 F / 27 M", "skin_tone": null, "industry_funded": false, "quote": "51% (κ = 0.28) for Polar", "location": "Abstract", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-polar-vantage-v-sleep_stages-kappa", "study_id": "miller2022", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.28, "value_text": "κ = 0.28", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night, 9 h in bed, all 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"Cohen's kappa", "value": 0.52, "value_text": "κ = 0.52", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night, 9 h in bed, all devices worn together", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y, 26 F / 27 M", "skin_tone": null, "industry_funded": false, "quote": "65% (κ = 0.52) for Somfit", "location": "Abstract", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-apple-watch-series-6-hr_sleep-icc", "study_id": "miller2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "hr_sleep", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.96, "value_text": "ICC 0.96", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 1.5 bpm", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-apple-watch-series-6-hr_sleep-mae_bpm", "study_id": "miller2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "hr_sleep", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 1.5, "value_text": "1.5 bpm (absolute bias)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Absolute Bias: Heart Rate (bpm) 1.5 ± 1.5 5.4 ± 12.6 1.5 ± 1.9 1.8 ± 4.1 0.7 ± 0.8 2.6 ± 6.3", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-apple-watch-series-6-hrv_rmssd-icc", "study_id": "miller2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "hrv_rmssd", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.67, "value_text": "ICC 0.67", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 22.5 ms", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-apple-watch-series-6-hrv_rmssd-mae_ms", "study_id": "miller2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "hrv_rmssd", "statistic": "mae_ms", "statistic_label": "Mean absolute error (absolute bias)", "value": 22.5, "value_text": "22.5 ms (absolute bias)", "unit": "ms", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "HRV (RMSSD, ms) 22.5 ± 19.2 33.1 ± 39.9 18.8 ± 34.0 18.9 ± 35.9 4.7 ± 3.6 24.0 ± 35.0", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-garmin-forerunner-245-music-hr_sleep-icc", "study_id": "miller2022", "device": "Garmin Forerunner 245 Music", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-forerunner-245", "metric": "hr_sleep", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.41, "value_text": "ICC 0.41", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 5.4 bpm", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": "Garmin HRV and HR came from a 3-min manual test while awake, not from sleep", "doi": "10.3390/s22166317" }, { "id": "miller2022-garmin-forerunner-245-music-hr_sleep-mae_bpm", "study_id": "miller2022", "device": "Garmin Forerunner 245 Music", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-forerunner-245", "metric": "hr_sleep", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 5.4, "value_text": "5.4 bpm (absolute bias)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Absolute Bias: Heart Rate (bpm) 1.5 ± 1.5 5.4 ± 12.6 1.5 ± 1.9 1.8 ± 4.1 0.7 ± 0.8 2.6 ± 6.3", "location": "Full text, Table 6", "note": "Garmin HRV and HR came from a 3-min manual test while awake, not from sleep", "doi": "10.3390/s22166317" }, { "id": "miller2022-garmin-forerunner-245-music-hrv_rmssd-icc", "study_id": "miller2022", "device": "Garmin Forerunner 245 Music", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-forerunner-245", "metric": "hrv_rmssd", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.24, "value_text": "ICC 0.24", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 33.1 ms", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": "Garmin HRV and HR came from a 3-min manual test while awake, not from sleep", "doi": "10.3390/s22166317" }, { "id": "miller2022-garmin-forerunner-245-music-hrv_rmssd-mae_ms", "study_id": "miller2022", "device": "Garmin Forerunner 245 Music", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-forerunner-245", "metric": "hrv_rmssd", "statistic": "mae_ms", "statistic_label": "Mean absolute error (absolute bias)", "value": 33.1, "value_text": "33.1 ms (absolute bias)", "unit": "ms", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "HRV (RMSSD, ms) 22.5 ± 19.2 33.1 ± 39.9 18.8 ± 34.0 18.9 ± 35.9 4.7 ± 3.6 24.0 ± 35.0", "location": "Full text, Table 6", "note": "Garmin HRV and HR came from a 3-min manual test while awake, not from sleep", "doi": "10.3390/s22166317" }, { "id": "miller2022-polar-vantage-v-hr_sleep-icc", "study_id": "miller2022", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "hr_sleep", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.93, "value_text": "ICC 0.93", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 1.5 bpm", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": "Polar sampled HRV over 4-h periods within sleep", "doi": "10.3390/s22166317" }, { "id": "miller2022-polar-vantage-v-hr_sleep-mae_bpm", "study_id": "miller2022", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "hr_sleep", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 1.5, "value_text": "1.5 bpm (absolute bias)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Absolute Bias: Heart Rate (bpm) 1.5 ± 1.5 5.4 ± 12.6 1.5 ± 1.9 1.8 ± 4.1 0.7 ± 0.8 2.6 ± 6.3", "location": "Full text, Table 6", "note": "Polar sampled HRV over 4-h periods within sleep", "doi": "10.3390/s22166317" }, { "id": "miller2022-polar-vantage-v-hrv_rmssd-icc", "study_id": "miller2022", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "hrv_rmssd", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.65, "value_text": "ICC 0.65", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 18.8 ms", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": "Polar sampled HRV over 4-h periods within sleep", "doi": "10.3390/s22166317" }, { "id": "miller2022-polar-vantage-v-hrv_rmssd-mae_ms", "study_id": "miller2022", "device": "Polar Vantage V", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-vantage-v", "metric": "hrv_rmssd", "statistic": "mae_ms", "statistic_label": "Mean absolute error (absolute bias)", "value": 18.8, "value_text": "18.8 ms (absolute bias)", "unit": "ms", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "HRV (RMSSD, ms) 22.5 ± 19.2 33.1 ± 39.9 18.8 ± 34.0 18.9 ± 35.9 4.7 ± 3.6 24.0 ± 35.0", "location": "Full text, Table 6", "note": "Polar sampled HRV over 4-h periods within sleep", "doi": "10.3390/s22166317" }, { "id": "miller2022-oura-ring-gen2-hr_sleep-icc", "study_id": "miller2022", "device": "Oura Ring Gen2", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "hr_sleep", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.85, "value_text": "ICC 0.85", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 1.8 bpm", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-oura-ring-gen2-hr_sleep-mae_bpm", "study_id": "miller2022", "device": "Oura Ring Gen2", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "hr_sleep", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 1.8, "value_text": "1.8 bpm (absolute bias)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Absolute Bias: Heart Rate (bpm) 1.5 ± 1.5 5.4 ± 12.6 1.5 ± 1.9 1.8 ± 4.1 0.7 ± 0.8 2.6 ± 6.3", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-oura-ring-gen2-hrv_rmssd-icc", "study_id": "miller2022", "device": "Oura Ring Gen2", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "hrv_rmssd", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.63, "value_text": "ICC 0.63", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 18.9 ms", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-oura-ring-gen2-hrv_rmssd-mae_ms", "study_id": "miller2022", "device": "Oura Ring Gen2", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "hrv_rmssd", "statistic": "mae_ms", "statistic_label": "Mean absolute error (absolute bias)", "value": 18.9, "value_text": "18.9 ms (absolute bias)", "unit": "ms", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "HRV (RMSSD, ms) 22.5 ± 19.2 33.1 ± 39.9 18.8 ± 34.0 18.9 ± 35.9 4.7 ± 3.6 24.0 ± 35.0", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-whoop-3-0-hr_sleep-icc", "study_id": "miller2022", "device": "WHOOP 3.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-3", "metric": "hr_sleep", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.99, "value_text": "ICC 0.99", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 0.7 bpm", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": true, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": "Raw R-R intervals provided by the manufacturer", "doi": "10.3390/s22166317" }, { "id": "miller2022-whoop-3-0-hr_sleep-mae_bpm", "study_id": "miller2022", "device": "WHOOP 3.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-3", "metric": "hr_sleep", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 0.7, "value_text": "0.7 bpm (absolute bias)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": true, "quote": "Absolute Bias: Heart Rate (bpm) 1.5 ± 1.5 5.4 ± 12.6 1.5 ± 1.9 1.8 ± 4.1 0.7 ± 0.8 2.6 ± 6.3", "location": "Full text, Table 6", "note": "Raw R-R intervals provided by the manufacturer", "doi": "10.3390/s22166317" }, { "id": "miller2022-whoop-3-0-hrv_rmssd-icc", "study_id": "miller2022", "device": "WHOOP 3.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-3", "metric": "hrv_rmssd", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.99, "value_text": "ICC 0.99", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 4.7 ms", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": true, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": "Raw R-R intervals provided by the manufacturer", "doi": "10.3390/s22166317" }, { "id": "miller2022-whoop-3-0-hrv_rmssd-mae_ms", "study_id": "miller2022", "device": "WHOOP 3.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-3", "metric": "hrv_rmssd", "statistic": "mae_ms", "statistic_label": "Mean absolute error (absolute bias)", "value": 4.7, "value_text": "4.7 ms (absolute bias)", "unit": "ms", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": true, "quote": "HRV (RMSSD, ms) 22.5 ± 19.2 33.1 ± 39.9 18.8 ± 34.0 18.9 ± 35.9 4.7 ± 3.6 24.0 ± 35.0", "location": "Full text, Table 6", "note": "Raw R-R intervals provided by the manufacturer", "doi": "10.3390/s22166317" }, { "id": "miller2022-somfit-hr_sleep-icc", "study_id": "miller2022", "device": "Somfit", "brand": "other", "brand_name": "Other", "device_slug": "somfit", "metric": "hr_sleep", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.65, "value_text": "ICC 0.65", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 2.6 bpm", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-somfit-hr_sleep-mae_bpm", "study_id": "miller2022", "device": "Somfit", "brand": "other", "brand_name": "Other", "device_slug": "somfit", "metric": "hr_sleep", "statistic": "mae_bpm", "statistic_label": "Mean absolute error", "value": 2.6, "value_text": "2.6 bpm (absolute bias)", "unit": "bpm", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Absolute Bias: Heart Rate (bpm) 1.5 ± 1.5 5.4 ± 12.6 1.5 ± 1.9 1.8 ± 4.1 0.7 ± 0.8 2.6 ± 6.3", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-somfit-hrv_rmssd-icc", "study_id": "miller2022", "device": "Somfit", "brand": "other", "brand_name": "Other", "device_slug": "somfit", "metric": "hrv_rmssd", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.69, "value_text": "ICC 0.69", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "absolute bias 24.0 ms", "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "Intraclass Correlations: Heart Rate (bpm) 0.96 0.41 0.93 0.85 0.99 0.65 HRV (RMSSD, ms) 0.67 0.24 0.65 0.63 0.99 0.69", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "miller2022-somfit-hrv_rmssd-mae_ms", "study_id": "miller2022", "device": "Somfit", "brand": "other", "brand_name": "Other", "device_slug": "somfit", "metric": "hrv_rmssd", "statistic": "mae_ms", "statistic_label": "Mean absolute error (absolute bias)", "value": 24, "value_text": "24.0 ms (absolute bias)", "unit": "ms", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Overnight, sleep laboratory", "n": 53, "n_note": null, "population": "Healthy adults 25.4 y", "skin_tone": null, "industry_funded": false, "quote": "HRV (RMSSD, ms) 22.5 ± 19.2 33.1 ± 39.9 18.8 ± 34.0 18.9 ± 35.9 4.7 ± 3.6 24.0 ± 35.0", "location": "Full text, Table 6", "note": null, "doi": "10.3390/s22166317" }, { "id": "schyvens2025-whoop-4-0-sleep_stages-kappa", "study_id": "schyvens2025", "device": "WHOOP 4.0", "brand": "whoop", "brand_name": "WHOOP", "device_slug": "whoop-4", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.37, "value_text": "κ = 0.37", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 40, "n_note": "device subgroup of 62 participants", "population": "Adults, mean age 46.0 y (device subgroup)", "skin_tone": null, "industry_funded": false, "quote": "Whoop 4.0 (κ = 0.37)", "location": "Full text, Results and Table 7", "note": null, "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-withings-scanwatch-sleep_stages-kappa", "study_id": "schyvens2025", "device": "Withings ScanWatch", "brand": "withings", "brand_name": "Withings", "device_slug": "withings-scanwatch", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.22, "value_text": "κ = 0.22", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 41, "n_note": "device subgroup of 62 participants", "population": "Adults, mean age 46.0 y (device subgroup)", "skin_tone": null, "industry_funded": false, "quote": "the Withings Scanwatch (κ = 0.22)", "location": "Full text, Results and Table 7", "note": null, "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "schyvens2025-garmin-vivosmart-4-sleep_stages-kappa", "study_id": "schyvens2025", "device": "Garmin Vivosmart 4", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-vivosmart-4", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.21, "value_text": "κ = 0.21", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Sleep laboratory, 1 night", "n": 25, "n_note": "device subgroup of 62 participants", "population": "Adults, mean age 46.0 y (device subgroup)", "skin_tone": null, "industry_funded": false, "quote": "the Garmin Vivosmart 4 (κ = 0.21)", "location": "Full text, Results and Table 7", "note": null, "doi": "10.1093/sleepadvances/zpaf021" }, { "id": "lee2023-google-pixel-watch-sleep_stages-kappa", "study_id": "lee2023", "device": "Google Pixel Watch", "brand": "google", "brand_name": "Google", "device_slug": "google-pixel-watch", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.4, "value_text": "κ = 0.4", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "macro F1 0.57; accuracy 63.5%", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 30, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Google Pixel Watch (n=30) 0.6355", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "lee2023-google-pixel-watch-sleep_stages-agreement_pct", "study_id": "lee2023", "device": "Google Pixel Watch", "brand": "google", "brand_name": "Google", "device_slug": "google-pixel-watch", "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 63.5, "value_text": "63.5%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 30, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Google Pixel Watch (n=30) 0.6355", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "lee2023-samsung-galaxy-watch5-sleep_stages-kappa", "study_id": "lee2023", "device": "Samsung Galaxy Watch5", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-5", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.42, "value_text": "κ = 0.42", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "macro F1 0.58; accuracy 64.9%", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 22, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Galaxy Watch 5 (n=22) 0.6494", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "lee2023-samsung-galaxy-watch5-sleep_stages-agreement_pct", "study_id": "lee2023", "device": "Samsung Galaxy Watch5", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-5", "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 64.9, "value_text": "64.9%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 22, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Galaxy Watch 5 (n=22) 0.6494", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "lee2023-fitbit-sense-2-sleep_stages-kappa", "study_id": "lee2023", "device": "Fitbit Sense 2", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense-2", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.42, "value_text": "κ = 0.42", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "macro F1 0.58; accuracy 64.6%", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 26, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Fitbit Sense 2 (n=26) 0.6464", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "lee2023-fitbit-sense-2-sleep_stages-agreement_pct", "study_id": "lee2023", "device": "Fitbit Sense 2", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense-2", "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 64.6, "value_text": "64.6%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 26, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Fitbit Sense 2 (n=26) 0.6464", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "lee2023-apple-watch-series-8-sleep_stages-kappa", "study_id": "lee2023", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.3, "value_text": "κ = 0.3", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "macro F1 0.49; accuracy 56.4%", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 26, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Apple Watch 8 (n=26) 0.5640", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "lee2023-apple-watch-series-8-sleep_stages-agreement_pct", "study_id": "lee2023", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 56.4, "value_text": "56.4%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 26, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Apple Watch 8 (n=26) 0.5640", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "lee2023-oura-ring-gen3-sleep_stages-kappa", "study_id": "lee2023", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "sleep_stages", "statistic": "kappa", "statistic_label": "Cohen's kappa", "value": 0.35, "value_text": "κ = 0.35", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "macro F1 0.52; accuracy 54.3%", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 53, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Oura Ring 3 (n=53) 0.5427", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "lee2023-oura-ring-gen3-sleep_stages-agreement_pct", "study_id": "lee2023", "device": "Oura Ring Gen3", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen3", "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 54.3, "value_text": "54.3%", "unit": "%", "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Two Korean sleep centres, in-lab PSG", "n": 53, "n_note": null, "population": "Patients and volunteers at a tertiary hospital and a sleep clinic", "skin_tone": null, "industry_funded": false, "quote": "Oura Ring 3 (n=53) 0.5427", "location": "Full text, Table 2", "note": null, "doi": "10.2196/50983" }, { "id": "kristiansson2023-oura-ring-gen2-energy-r", "study_id": "kristiansson2023", "device": "Oura Ring (Gen2)", "brand": "oura", "brand_name": "Oura", "device_slug": "oura-ring-gen2", "metric": "energy", "statistic": "r", "statistic_label": "Pearson correlation", "value": 0.93, "value_text": "r = 0.93 (lab)", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "underestimated EE as intensity increased", "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Laboratory activities", "n": null, "n_note": null, "population": "Adults (lab phase); 32 in free-living phase", "skin_tone": null, "industry_funded": false, "quote": "Strong correlations were shown for Oura versus indirect calorimetry in the laboratory (r = 0.93)", "location": "Abstract", "note": null, "doi": "10.1186/s12874-023-01868-x" }, { "id": "kostrna2026-apple-watch-series-8-energy-bias", "study_id": "kostrna2026", "device": "Apple Watch Series 8", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-8", "metric": "energy", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": 21.6, "value_text": "+21.6 kcal", "unit": "kcal", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "physical activity energy expenditure, 10 min", "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "10-min recumbent cycling intervals", "n": 52, "n_note": null, "population": "Hispanic adults, Fitzpatrick III–V", "skin_tone": "Fitzpatrick III–V", "industry_funded": false, "quote": "Apple 21.60 (36.63)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pone.0353261" }, { "id": "kostrna2026-garmin-forerunner-955-energy-bias", "study_id": "kostrna2026", "device": "Garmin Forerunner 955", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "energy", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": 68.61, "value_text": "+68.61 kcal", "unit": "kcal", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "physical activity energy expenditure, 10 min", "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "10-min recumbent cycling intervals", "n": 51, "n_note": null, "population": "Hispanic adults, Fitzpatrick III–V", "skin_tone": "Fitzpatrick III–V", "industry_funded": false, "quote": "Garmin 68.61 (55.86)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pone.0353261" }, { "id": "kostrna2026-samsung-galaxy-watch5-energy-bias", "study_id": "kostrna2026", "device": "Samsung Galaxy Watch5", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-5", "metric": "energy", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": 56.76, "value_text": "+56.76 kcal", "unit": "kcal", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "physical activity energy expenditure, 10 min", "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "10-min recumbent cycling intervals", "n": 50, "n_note": null, "population": "Hispanic adults, Fitzpatrick III–V", "skin_tone": "Fitzpatrick III–V", "industry_funded": false, "quote": "Samsung 56.76 (42.03)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pone.0353261" }, { "id": "kostrna2026-fitbit-sense-2-energy-bias", "study_id": "kostrna2026", "device": "Fitbit Sense 2", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-sense-2", "metric": "energy", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": 3.14, "value_text": "+3.14 kcal", "unit": "kcal", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "physical activity energy expenditure, 10 min", "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "10-min recumbent cycling intervals", "n": 44, "n_note": null, "population": "Hispanic adults, Fitzpatrick III–V", "skin_tone": "Fitzpatrick III–V", "industry_funded": false, "quote": "Fitbit 3.14 (40.95)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pone.0353261" }, { "id": "le2022-apple-watch-series-6-energy-mape_pct", "study_id": "le2022", "device": "Apple Watch Series 6", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch-series-6", "metric": "energy", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 19.8, "value_text": "19.8% walk / 24.4% run", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": "walking", "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Outdoor 2-km walk (6 km/h) and run (10 km/h)", "n": 20, "n_note": null, "population": "Young normal-weight Chinese adults", "skin_tone": null, "industry_funded": false, "quote": "The mean absolute percentage error (MAPE) was 19.8% for AW, 32.0% for GF, and 9.9% for HW", "location": "Abstract", "note": null, "doi": "10.3389/fphys.2022.995575" }, { "id": "le2022-garmin-fenix-6-energy-mape_pct", "study_id": "le2022", "device": "Garmin Fenix 6", "brand": "garmin", "brand_name": "Garmin", "device_slug": "garmin-fenix-6", "metric": "energy", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 32, "value_text": "32.0% walk / 21.8% run", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": "walking", "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Outdoor 2-km walk (6 km/h) and run (10 km/h)", "n": 20, "n_note": null, "population": "Young normal-weight Chinese adults", "skin_tone": null, "industry_funded": false, "quote": "The mean absolute percentage error (MAPE) was 19.8% for AW, 32.0% for GF, and 9.9% for HW", "location": "Abstract", "note": null, "doi": "10.3389/fphys.2022.995575" }, { "id": "le2022-huawei-watch-gt-2e-energy-mape_pct", "study_id": "le2022", "device": "Huawei Watch GT 2e", "brand": "other", "brand_name": "Other", "device_slug": null, "metric": "energy", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 9.9, "value_text": "9.9% walk / 11.9% run", "unit": "%", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": "walking", "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Outdoor 2-km walk (6 km/h) and run (10 km/h)", "n": 20, "n_note": null, "population": "Young normal-weight Chinese adults", "skin_tone": null, "industry_funded": false, "quote": "The mean absolute percentage error (MAPE) was 19.8% for AW, 32.0% for GF, and 9.9% for HW", "location": "Abstract", "note": null, "doi": "10.3389/fphys.2022.995575" }, { "id": "ferreira2026-samsung-galaxy-watch6-watch7-energy-mape_pct", "study_id": "ferreira2026", "device": "Samsung Galaxy Watch6 / Watch7", "brand": "samsung", "brand_name": "Samsung", "device_slug": null, "metric": "energy", "statistic": "mape_pct", "statistic_label": "Mean absolute percentage error", "value": 10.1, "value_text": "10.10–12.55%", "unit": "%", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "27-min intermittent treadmill running", "n": 148, "n_note": null, "population": "Healthy adults, 80 M / 68 W", "skin_tone": null, "industry_funded": false, "quote": "Mean absolute percentage error values ranged from 10.10% to 12.55%", "location": "Abstract", "note": "Range across test conditions; not ranked against single values.", "doi": "10.2196/83090" }, { "id": "shcherbina2017-apple-watch-hr_exercise-finding", "study_id": "shcherbina2017", "device": "Apple Watch", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch", "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Lowest overall error of 7 devices", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Sitting, walking, running, cycling", "n": 60, "n_note": null, "population": "Volunteers of diverse age, BMI and skin tone, 29 M / 31 F", "skin_tone": "Error higher for darker skin tone", "industry_funded": false, "quote": "The Apple Watch achieved the lowest overall error in both HR and EE, while the Samsung Gear S2 reported the highest", "location": "Abstract", "note": null, "doi": "10.3390/jpm7020003" }, { "id": "shcherbina2017-samsung-gear-s2-hr_exercise-finding", "study_id": "shcherbina2017", "device": "Samsung Gear S2", "brand": "samsung", "brand_name": "Samsung", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Highest overall error of 7 devices", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Sitting, walking, running, cycling", "n": 60, "n_note": null, "population": "Volunteers of diverse age, BMI and skin tone, 29 M / 31 F", "skin_tone": "Error higher for darker skin tone", "industry_funded": false, "quote": "The Apple Watch achieved the lowest overall error in both HR and EE, while the Samsung Gear S2 reported the highest", "location": "Abstract", "note": null, "doi": "10.3390/jpm7020003" }, { "id": "shcherbina2017-fitbit-surge-energy-finding", "study_id": "shcherbina2017", "device": "Fitbit Surge", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": null, "metric": "energy", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "No device achieved EE error below 20%", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Sitting, walking, running, cycling", "n": 60, "n_note": null, "population": "Volunteers of diverse age, BMI and skin tone, 29 M / 31 F", "skin_tone": "Error higher for darker skin tone", "industry_funded": false, "quote": "No device achieved an error in EE below 20 percent", "location": "Abstract", "note": null, "doi": "10.3390/jpm7020003" }, { "id": "shcherbina2017-apple-watch-energy-finding", "study_id": "shcherbina2017", "device": "Apple Watch", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch", "metric": "energy", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Lowest EE error of 7 devices, but no device below 20%", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Sitting, walking, running, cycling", "n": 60, "n_note": null, "population": "Volunteers of diverse age, BMI and skin tone, 29 M / 31 F", "skin_tone": "Error higher for darker skin tone", "industry_funded": false, "quote": "No device achieved an error in EE below 20 percent", "location": "Abstract", "note": null, "doi": "10.3390/jpm7020003" }, { "id": "gillinov2017-polar-h7-chest-strap-ecg-hr_exercise-ccc", "study_id": "gillinov2017", "device": "Polar H7 (chest strap, ECG)", "brand": "polar", "brand_name": "Polar", "device_slug": "polar-h7", "metric": "hr_exercise", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.996, "value_text": "rc = 0.996", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": "all exercise conditions", "reference": "ECG", "reference_class": "ecg", "setting": "Gillinov: treadmill, bike, elliptical", "n": 50, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "Polar H7) had the best agreement with ECG (rc = 0.996)", "location": "Abstract", "note": "ECG chest strap, not optical PPG", "doi": "10.1249/MSS.0000000000001284" }, { "id": "gillinov2017-apple-watch-hr_exercise-ccc", "study_id": "gillinov2017", "device": "Apple Watch", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch", "metric": "hr_exercise", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.92, "value_text": "rc = 0.92", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": "all exercise conditions", "reference": "ECG", "reference_class": "ecg", "setting": "Gillinov: treadmill, bike, elliptical", "n": 50, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "the Apple Watch (rc = 0.92)", "location": "Abstract", "note": null, "doi": "10.1249/MSS.0000000000001284" }, { "id": "gillinov2017-tomtom-spark-cardio-hr_exercise-ccc", "study_id": "gillinov2017", "device": "TomTom Spark Cardio", "brand": "other", "brand_name": "Other", "device_slug": null, "metric": "hr_exercise", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.83, "value_text": "rc = 0.83", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": "all exercise conditions", "reference": "ECG", "reference_class": "ecg", "setting": "Gillinov: treadmill, bike, elliptical", "n": 50, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "the TomTom Spark (rc = 0.83)", "location": "Abstract", "note": null, "doi": "10.1249/MSS.0000000000001284" }, { "id": "gillinov2017-garmin-forerunner-235-hr_exercise-ccc", "study_id": "gillinov2017", "device": "Garmin Forerunner 235", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "hr_exercise", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.81, "value_text": "rc = 0.81", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": "all exercise conditions", "reference": "ECG", "reference_class": "ecg", "setting": "Gillinov: treadmill, bike, elliptical", "n": 50, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "the Garmin Forerunner (rc = 0.81)", "location": "Abstract", "note": null, "doi": "10.1249/MSS.0000000000001284" }, { "id": "gillinov2017-scosche-rhythm-hr_exercise-ccc", "study_id": "gillinov2017", "device": "Scosche Rhythm+", "brand": "other", "brand_name": "Other", "device_slug": null, "metric": "hr_exercise", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.75, "value_text": "rc = 0.75", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": "all exercise conditions", "reference": "ECG", "reference_class": "ecg", "setting": "Gillinov: treadmill, bike, elliptical", "n": 50, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "rc = 0.75 and rc = 0.67, respectively", "location": "Abstract", "note": null, "doi": "10.1249/MSS.0000000000001284" }, { "id": "gillinov2017-fitbit-blaze-hr_exercise-ccc", "study_id": "gillinov2017", "device": "Fitbit Blaze", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": null, "metric": "hr_exercise", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.67, "value_text": "rc = 0.67", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": "all exercise conditions", "reference": "ECG", "reference_class": "ecg", "setting": "Gillinov: treadmill, bike, elliptical", "n": 50, "n_note": null, "population": "Healthy adults", "skin_tone": null, "industry_funded": false, "quote": "rc = 0.75 and rc = 0.67, respectively", "location": "Abstract", "note": null, "doi": "10.1249/MSS.0000000000001284" }, { "id": "wallen2016-4-wrist-devices-apple-watch-fitbit-charge-hr-samsung-gear-s-mio-alpha-hr_exercise-finding", "study_id": "wallen2016", "device": "4 wrist devices (Apple Watch, Fitbit Charge HR, Samsung Gear S, Mio Alpha)", "brand": "other", "brand_name": "Other", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "HR error 1–9%; EE error 9–43%", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Rest, treadmill, cycling (~1 h)", "n": 22, "n_note": null, "population": "Healthy volunteers 24 y, 50% F", "skin_tone": null, "industry_funded": false, "quote": "The percentage error for heart rate was small across the devices (range: 1-9%) but greater for energy expenditure (9-43%)", "location": "Abstract", "note": null, "doi": "10.1371/journal.pone.0154420" }, { "id": "nuuttila2021-polar-vantage-v2-hrv_rmssd-icc", "study_id": "nuuttila2021", "device": "Polar Vantage V2", "brand": "polar", "brand_name": "Polar", "device_slug": null, "metric": "hrv_rmssd", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.931, "value_text": "ICC 0.931 (nocturnal LnRMSSD)", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "Overestimated LnRMSSD by 0.17–0.20", "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Supine lab (5 min) and home sleep (4 h)", "n": 29, "n_note": null, "population": "Recreationally endurance-trained adults", "skin_tone": null, "industry_funded": true, "quote": "LnRMSSD: 0.931, p < 0.001", "location": "Abstract", "note": null, "doi": "10.3390/s22010137" }, { "id": "nuuttila2021-polar-vantage-v2-hr_sleep-icc", "study_id": "nuuttila2021", "device": "Polar Vantage V2", "brand": "polar", "brand_name": "Polar", "device_slug": null, "metric": "hr_sleep", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.998, "value_text": "ICC 0.998", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Supine lab (5 min) and home sleep (4 h)", "n": 29, "n_note": null, "population": "Recreationally endurance-trained adults", "skin_tone": null, "industry_funded": true, "quote": "HR: 0.998, p < 0.001", "location": "Abstract", "note": null, "doi": "10.3390/s22010137" }, { "id": "shumate2021-polar-vantage-m-hr_exercise-finding", "study_id": "shumate2021", "device": "Polar Vantage M", "brand": "polar", "brand_name": "Polar", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Good ICC at stages 0–2; poor at stages 3–5 (ICC < 0.50)", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Bruce treadmill protocol, 2 days", "n": 28, "n_note": null, "population": "Healthy adults 26.1 y, 16 M / 14 F", "skin_tone": null, "industry_funded": false, "quote": "Poor validity was demonstrated on day 1 and day 2 for stages 3-5 (ICC < 0.50)", "location": "Abstract", "note": null, "doi": "10.7717/peerj.10893" }, { "id": "theurl2023-garmin-vivoactive-4-hrv_rmssd-ccc", "study_id": "theurl2023", "device": "Garmin Vivoactive 4", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "hrv_rmssd", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.6617, "value_text": "ρc = 0.66 (moderate)", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "30-min standardised recording", "n": 263, "n_note": null, "population": "104 post-STEMI, 129 post-stroke, 30 controls", "skin_tone": null, "industry_funded": false, "quote": "the square mean root of the sum of squares of adjacent NN-interval differences (rMSSD; ρc = 0.6617) showed only moderate concordance", "location": "Abstract", "note": null, "doi": "10.1093/ehjdh/ztad022" }, { "id": "theurl2023-garmin-vivoactive-4-hr_rest-ccc", "study_id": "theurl2023", "device": "Garmin Vivoactive 4", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "hr_rest", "statistic": "ccc", "statistic_label": "Lin's concordance correlation", "value": 0.9998, "value_text": "ρc = 0.9998", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "30-min standardised recording", "n": 263, "n_note": null, "population": "104 post-STEMI, 129 post-stroke, 30 controls", "skin_tone": null, "industry_funded": false, "quote": "the mean heart rate (ρc = 0.9998)", "location": "Abstract", "note": null, "doi": "10.1093/ehjdh/ztad022" }, { "id": "giggins2022-withings-scanwatch-hr_rest-finding", "study_id": "giggins2022", "device": "Withings ScanWatch", "brand": "withings", "brand_name": "Withings", "device_slug": "withings-scanwatch", "metric": "hr_rest", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "MAPE < 10% in all domains except shopping (10.8%); < 5% when sedentary", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "12-h free-living", "n": 7, "n_note": null, "population": "Adults 64 ± 10 y", "skin_tone": null, "industry_funded": false, "quote": "the ScanWatch measured HR with MAPE values <10%, except for the shopping activity domain (MAPE=10.8%)", "location": "Abstract", "note": null, "doi": "10.2196/34280" }, { "id": "inoue2026-samsung-galaxy-watch6-hr_exercise-bias", "study_id": "inoue2026", "device": "Samsung Galaxy Watch6", "brand": "samsung", "brand_name": "Samsung", "device_slug": null, "metric": "hr_exercise", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -2.67, "value_text": "−2.67 bpm (LoA −16.90 to 11.57)", "unit": "bpm", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "Maximal incremental treadmill test", "n": 55, "n_note": null, "population": "Healthy adults 30.3 y, 30 M / 25 W", "skin_tone": null, "industry_funded": false, "quote": "an overall mean bias of -2.67 bpm and wide limits of agreement (-16.90 to 11.57 bpm)", "location": "Abstract", "note": null, "doi": "10.2196/81917" }, { "id": "lee2026-apple-watch-hr_exercise-finding", "study_id": "lee2026", "device": "Apple Watch", "brand": "apple", "brand_name": "Apple", "device_slug": "apple-watch", "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Only device with no significant HR difference from ECG in resistance exercise", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG", "reference_class": "ecg", "setting": "Endurance and resistance exercise", "n": 62, "n_note": null, "population": "Healthy adult men", "skin_tone": null, "industry_funded": false, "quote": "whereas during resistance exercise, only the Apple Watch showed no significant difference from the ECG", "location": "Abstract", "note": null, "doi": "10.3390/s26082526" }, { "id": "walzel2026-samsung-galaxy-watch5-bp-bias", "study_id": "walzel2026", "device": "Samsung Galaxy Watch5", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-5", "metric": "bp", "statistic": "bias", "statistic_label": "Mean bias (signed)", "value": -0.34, "value_text": "SBP −0.34 / DBP +0.62 mmHg", "unit": "mmHg", "higher_is_better": null, "rankable": false, "secondary": "MD 3.4/5.1 mmHg when BP was 10 mmHg from the calibration point", "subgroup": null, "reference": "Validated cuff (Omron M4)", "reference_class": "cuff", "setting": "28 days after one calibration", "n": 37, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": false, "quote": "Bland-Altman analysis revealed negligible MD for SBP (-0.34 mmHg) and DBP (0.62 mmHg)", "location": "Abstract", "note": null, "doi": "10.1177/20552076261415923" }, { "id": "falter2022-samsung-galaxy-watch-active2-bp-sensitivity_pct", "study_id": "falter2022", "device": "Samsung Galaxy Watch Active2", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-active-2", "metric": "bp", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 83, "value_text": "83% (spec 41%) for hypertension", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": "specificity 41%", "subgroup": null, "reference": "24-h ambulatory BP monitor", "reference_class": "abpm", "setting": "24-h ambulatory BP monitoring", "n": 40, "n_note": null, "population": "Patients referred for ABPM", "skin_tone": null, "industry_funded": false, "quote": "Sensitivity and specificity for detecting systolic and/or diastolic hypertension were 83 and 41%, respectively", "location": "Abstract", "note": null, "doi": "10.3389/fcvm.2022.958212" }, { "id": "jung2023-samsung-galaxy-watch-resp_rate-rmse_bpm", "study_id": "jung2023", "device": "Samsung Galaxy Watch", "brand": "samsung", "brand_name": "Samsung", "device_slug": null, "metric": "resp_rate", "statistic": "rmse_bpm", "statistic_label": "Root-mean-square error", "value": 1.13, "value_text": "RMSE 1.13 breaths/min (overnight average)", "unit": "breaths/min", "higher_is_better": false, "rankable": true, "secondary": "1.62 continuous; accuracy fell in severe OSA", "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "Overnight PSG, nasal thermocouple reference", "n": 195, "n_note": null, "population": "Sleep clinic patients, normal to severe OSA", "skin_tone": null, "industry_funded": true, "quote": "the root mean squared error (RMSE) of the average overnight RR and continuous RR measurements were 1.13 bpm and 1.62 bpm", "location": "Abstract", "note": null, "doi": "10.3390/s23187976" }, { "id": "mendt2025-withings-pulse-hr-hr_exercise-finding", "study_id": "mendt2025", "device": "Withings Pulse HR", "brand": "withings", "brand_name": "Withings", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Good at rest and 2.7 km/h (r ≥ 0.82); poor at higher speeds (r ≤ 0.33)", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Zephyr BioHarness / Faros)", "reference_class": "ecg", "setting": "Sitting, standing, Bruce treadmill stages 1–4", "n": 22, "n_note": null, "population": "Adults, 11 W / 11 M", "skin_tone": null, "industry_funded": false, "quote": "but this decreased with increasing speed (r ≤ 0.33, |bias| ≤ 11.7 bpm)", "location": "Abstract", "note": null, "doi": "10.3389/fphys.2025.1491401" }, { "id": "perez2019-apple-watch-irregular-rhythm-notification-af-ppv_pct", "study_id": "perez2019", "device": "Apple Watch (irregular rhythm notification)", "brand": "apple", "brand_name": "Apple", "device_slug": null, "metric": "af", "statistic": "ppv_pct", "statistic_label": "Positive predictive value", "value": 84, "value_text": "PPV 0.84 (95% CI 0.76–0.92)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "PPG irregular pulse notification", "reference": "ECG patch", "reference_class": "ecg", "setting": "Siteless pragmatic study; ECG patch after notification", "n": 419297, "n_note": null, "population": "Apple Watch users without self-reported AF (450 analysable ECG patches)", "skin_tone": null, "industry_funded": true, "quote": "the positive predictive value was 0.84 (95% CI, 0.76 to 0.92) for observing atrial fibrillation on the ECG simultaneously with a subsequent irregular pulse notification", "location": "Abstract", "note": null, "doi": "10.1056/NEJMoa1901183" }, { "id": "lubitz2022-fitbit-ppg-irregular-rhythm-algorithm-af-ppv_pct", "study_id": "lubitz2022", "device": "Fitbit (PPG irregular rhythm algorithm)", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": null, "metric": "af", "statistic": "ppv_pct", "statistic_label": "Positive predictive value", "value": 98.2, "value_text": "PPV 98.2% (95% CI 95.5–99.5%)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "PPG irregular rhythm detection", "reference": "ECG patch", "reference_class": "ecg", "setting": "Remote trial; 1-week ECG patch after detection", "n": 455699, "n_note": null, "population": "Fitbit users ≥ 22 y without AF, median 47 y, 71% female (225 with concurrent detection)", "skin_tone": null, "industry_funded": true, "quote": "resulting in an IHRD positive predictive value of 98.2% (95% CI, 95.5%-99.5%)", "location": "Abstract", "note": null, "doi": "10.1161/CIRCULATIONAHA.122.060291" }, { "id": "bumgarner2018-kardia-band-on-apple-watch-single-lead-ecg-af-sensitivity_pct", "study_id": "bumgarner2018", "device": "Kardia Band on Apple Watch (single-lead ECG)", "brand": "apple", "brand_name": "Apple", "device_slug": null, "metric": "af", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 93, "value_text": "Sens 93% / spec 84% (interpretable recordings)", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "automated ECG read; 57 of 169 recordings non-interpretable", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Before and after cardioversion", "n": 100, "n_note": null, "population": "Patients with AF presenting for cardioversion, 68 y", "skin_tone": null, "industry_funded": false, "quote": "the KB interpreted AF with 93% sensitivity, 84% specificity, and a K coefficient of 0.77", "location": "Abstract", "note": null, "doi": "10.1016/j.jacc.2018.03.003" }, { "id": "han2023-samsung-galaxy-watch-bp-bp-finding", "study_id": "han2023", "device": "Samsung Galaxy Watch (BP)", "brand": "samsung", "brand_name": "Samsung", "device_slug": null, "metric": "bp", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Pre/post calibration SBP error 6.8 ± 5.6 mmHg", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "Cuff used for calibration", "reference_class": "cuff", "setting": "Real-world, 4 weeks post calibration", "n": 760, "n_note": null, "population": "Galaxy Watch users in Korea, 43.7 y, 80.3% men", "skin_tone": null, "industry_funded": false, "quote": "The average pre-post calibration error for systolic BP (difference in 7-day BP before and after calibration), was 6.8 ± 5.6 mmHg", "location": "Abstract", "note": null, "doi": "10.1038/s41440-023-01215-z" }, { "id": "altini2021-oura-ring-research-multi-sensor-model-sleep_stages-agreement_pct", "study_id": "altini2021", "device": "Oura Ring (research multi-sensor model)", "brand": "oura", "brand_name": "Oura", "device_slug": null, "metric": "sleep_stages", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 79, "value_text": "79% (4-stage, research model)", "unit": "%", "higher_is_better": true, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "440 nights, 5-fold cross-validation of a research model", "n": 106, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": true, "quote": "Accuracy for 4-stage detection was 57% for the accelerometer-based model and 79% when including ANS-derived and circadian features", "location": "Abstract", "note": "Cross-validated research model by Oura-affiliated authors, not the shipped app output", "doi": "10.3390/s21134302" }, { "id": "altini2021-oura-ring-research-multi-sensor-model-sleep_wake-agreement_pct", "study_id": "altini2021", "device": "Oura Ring (research multi-sensor model)", "brand": "oura", "brand_name": "Oura", "device_slug": null, "metric": "sleep_wake", "statistic": "agreement_pct", "statistic_label": "Epoch-by-epoch agreement", "value": 96, "value_text": "96% (2-stage, research model)", "unit": "%", "higher_is_better": true, "rankable": false, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "440 nights, 5-fold cross-validation of a research model", "n": 106, "n_note": null, "population": "Adults", "skin_tone": null, "industry_funded": true, "quote": "96% for a full model that included ANS-derived and circadian features", "location": "Abstract", "note": "Cross-validated research model by Oura-affiliated authors, not the shipped app output", "doi": "10.3390/s21134302" }, { "id": "ibrahim2024-amazfit-cor-bip-hr_exercise-finding", "study_id": "ibrahim2024", "device": "Amazfit Cor / Bip", "brand": "amazfit", "brand_name": "Amazfit", "device_slug": null, "metric": "hr_exercise", "statistic": "finding", "statistic_label": "Study finding (no single number)", "value": null, "value_text": "Absolute percentage error within 10% at every stage", "unit": null, "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": null, "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Incremental treadmill test", "n": 51, "n_note": null, "population": "Patients with ischaemic heart disease", "skin_tone": null, "industry_funded": false, "quote": "At each stage, the absolute percentage error of the PPG was within 10% of the standard acceptable range", "location": "Abstract", "note": null, "doi": "10.1007/s13239-023-00693-z" }, { "id": "browne2024-samsung-galaxy-watch4-spo2-rmse_pct", "study_id": "browne2024", "device": "Samsung Galaxy Watch4", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-4", "metric": "spo2", "statistic": "rmse_pct", "statistic_label": "Root-mean-square error", "value": 2.54, "value_text": "RMSE 2.54 points (overnight, vs PSG oximetry)", "unit": "% points", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "PSG pulse oximetry", "reference_class": "psg", "setting": "In-lab overnight PSG, continuous SpO2", "n": 51, "n_note": null, "population": "Adults 22–78 y, 66.7% male; 9.8% African American, 25.5% Hispanic", "skin_tone": "Race/ethnicity reported, not skin tone", "industry_funded": true, "quote": "root-mean-square error of 2.54 (95% confidence interval, 2.34, 2.73)", "location": "Abstract", "note": null, "doi": "10.5664/jcsm.11178" }, { "id": "selder2023-fitbit-ionic-fibricheck-algorithm-af-sensitivity_pct", "study_id": "selder2023", "device": "Fitbit Ionic + FibriCheck algorithm", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": null, "metric": "af", "statistic": "sensitivity_pct", "statistic_label": "Sensitivity", "value": 97, "value_text": "Sens 97% / spec 100%", "unit": "%", "higher_is_better": null, "rankable": false, "secondary": null, "subgroup": "third-party PPG algorithm (FibriCheck), not Fitbit's own", "reference": "12-lead ECG", "reference_class": "ecg", "setting": "Around cardioversion, 1-min PPG", "n": 73, "n_note": null, "population": "Patients with AF admitted for cardioversion (AF prevalence ~50%)", "skin_tone": null, "industry_funded": false, "quote": "and 97%, 100%, 100%, 97%, and 99%, respectively", "location": "Abstract", "note": null, "doi": "10.2196/44642" }, { "id": "dhawale2026-ultrahuman-ring-air-vo2max-mae_mlkgmin", "study_id": "dhawale2026", "device": "Ultrahuman Ring AIR", "brand": "ultrahuman", "brand_name": "Ultrahuman", "device_slug": "ultrahuman-ring", "metric": "vo2max", "statistic": "mae_mlkgmin", "statistic_label": "Mean absolute error", "value": 4.68, "value_text": "MAE 4.68 mL/kg/min (r 0.79)", "unit": "mL/kg/min", "higher_is_better": false, "rankable": false, "secondary": null, "subgroup": null, "reference": "Indirect calorimetry", "reference_class": "indirect_calorimetry", "setting": "Single-site CPET cohort; model developed on 85, tested on 16", "n": 101, "n_note": null, "population": "South Asian cohort", "skin_tone": null, "industry_funded": true, "quote": "With a self-reported fitness level provided, the estimate agreed with CPET peak VO2 at MAE 4.68 mL·kg⁻¹·min⁻¹", "location": "Abstract", "note": "Company-authored preprint (not peer reviewed); the ring estimate was tuned on 85 of the 101 participants", "doi": "10.64898/2026.07.16.26358226" }, { "id": "kim2026-samsung-galaxy-watch5-skin_temp-r", "study_id": "kim2026", "device": "Samsung Galaxy Watch5", "brand": "samsung", "brand_name": "Samsung", "device_slug": "samsung-galaxy-watch-5", "metric": "skin_temp", "statistic": "r", "statistic_label": "Pearson correlation", "value": 0.423, "value_text": "r = 0.42 vs oral temperature", "unit": null, "higher_is_better": true, "rankable": true, "secondary": "Ovulation predicted within 3 days in 77.8% of cycles", "subgroup": null, "reference": "Oral thermometer", "reference_class": "oral_thermometer", "setting": "Nightly wrist skin temperature vs oral temperature on waking", "n": 85, "n_note": null, "population": "Women, 225 cycles (full analysis set)", "skin_tone": null, "industry_funded": true, "quote": "WST and oral temperature showed moderate correlation (FAS: r = 0.423", "location": "Abstract", "note": null, "doi": "10.1016/j.bios.2026.118755" }, { "id": "hermans2024-fitbit-charge-4-resp_rate-icc", "study_id": "hermans2024", "device": "Fitbit Charge 4", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-charge-4", "metric": "resp_rate", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.84, "value_text": "ICC 0.84 (COPD) / 0.77 (controls)", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "5 days free-living", "n": 55, "n_note": null, "population": "30 patients with COPD and 25 matched controls", "skin_tone": null, "industry_funded": false, "quote": "RR (ICC2,1=0.84 and ICC2,1=0.77, respectively)", "location": "Abstract", "note": null, "doi": "10.2196/56027" }, { "id": "hermans2024-fitbit-charge-4-hr_rest-icc", "study_id": "hermans2024", "device": "Fitbit Charge 4", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-charge-4", "metric": "hr_rest", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.8, "value_text": "ICC 0.80 (COPD) / 0.79 (controls)", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "ECG chest strap (Polar H7/H10)", "reference_class": "ecg", "setting": "5 days free-living", "n": 55, "n_note": null, "population": "30 patients with COPD and 25 matched controls", "skin_tone": null, "industry_funded": false, "quote": "RHR (ICC2,1=0.80 and ICC2,1=0.79, respectively)", "location": "Abstract", "note": null, "doi": "10.2196/56027" }, { "id": "hermans2024-fitbit-charge-4-spo2-icc", "study_id": "hermans2024", "device": "Fitbit Charge 4", "brand": "fitbit", "brand_name": "Fitbit", "device_slug": "fitbit-charge-4", "metric": "spo2", "statistic": "icc", "statistic_label": "Intraclass correlation", "value": 0.32, "value_text": "ICC 0.32 (COPD, overnight)", "unit": null, "higher_is_better": true, "rankable": true, "secondary": null, "subgroup": null, "reference": "Medical-grade pulse oximeter", "reference_class": "pulse_oximeter", "setting": "4 nights", "n": 30, "n_note": null, "population": "Patients with COPD", "skin_tone": null, "industry_funded": false, "quote": "The agreement in measuring oxygen saturation in patients with COPD was poor (ICC2,1=0.32)", "location": "Abstract", "note": null, "doi": "10.2196/56027" }, { "id": "budig2022-garmin-forerunner-945-sleep_tst-mae_min", "study_id": "budig2022", "device": "Garmin Forerunner 945", "brand": "garmin", "brand_name": "Garmin", "device_slug": null, "metric": "sleep_tst", "statistic": "mae_min", "statistic_label": "Mean absolute error", "value": 84.63, "value_text": "MAE 84.63 min (overestimate)", "unit": "min", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "1 night PSG + MSLT", "n": 49, "n_note": null, "population": "Adults with suspected sleep disorders, 30 M / 19 F", "skin_tone": null, "industry_funded": false, "quote": "Garmin had significant overestimation of TST, with MAE of 84.63 min and MAPE of 25.32%", "location": "Abstract", "note": null, "doi": "10.3390/s22239540" }, { "id": "budig2022-polar-ignite-sleep_tst-mae_min", "study_id": "budig2022", "device": "Polar Ignite", "brand": "polar", "brand_name": "Polar", "device_slug": null, "metric": "sleep_tst", "statistic": "mae_min", "statistic_label": "Mean absolute error", "value": 45.08, "value_text": "MAE 45.08 min (overestimate)", "unit": "min", "higher_is_better": false, "rankable": true, "secondary": null, "subgroup": null, "reference": "Polysomnography (PSG)", "reference_class": "psg", "setting": "1 night PSG + MSLT", "n": 49, "n_note": null, "population": "Adults with suspected sleep disorders, 30 M / 19 F", "skin_tone": null, "industry_funded": false, "quote": "Polar also had an overestimation of TST, with MAE of 45.08 min and MAPE of 13.80%", "location": "Abstract", "note": null, "doi": "10.3390/s22239540" } ] }