Wearable guides
Garmin Elevate v5 Optical Sensor: PPG Specs and Accuracy
Garmin's Elevate optical sensor uses multiple LEDs and detectors for wrist heart rate, HRV-derived features, and Pulse Ox on supported watches. Garmin does not publish a universal sampling rate, wavelength list or heart-rate accuracy figure for the sensor family, and accuracy varies with model, fit and activity.
Garmin's Elevate sensor generations use green light for optical heart rate and red/infrared light for Pulse Ox on supported products. Garmin does not publish a complete detector count, wavelength list or sampling specification across the product family, so hardware claims should be checked against the documentation for each model.
Independent results depend on the model and the task. Against ECG during treadmill, cycling and elliptical exercise, a Garmin Forerunner 235 reached a Lin's concordance of 0.81, versus 0.996 for a Polar H7 chest strap (Gillinov et al., 2017). In a sleep laboratory, a Garmin Forerunner 245 matched polysomnography on 50% of epochs for sleep stage plus wake and on 89% for sleep versus wake (Miller et al., 2022). In people with COPD, Garmin Vivosmart 4 SpO2 had a root mean squared error of 3.3% at rest against a fingertip pulse oximeter, rising to 6.1% after a sit-to-stand test (Støve et al., 2023).
HRV Status analyses wrist heart-rate readings during sleep. After seven nights the watch shows a seven-day HRV average, and after three weeks of consistent sleep data it compares that average with a personal baseline range (Garmin: HRV status). Body Battery is a 5–100 energy-reserve estimate based on heart rate variability, stress, sleep quality and activity (Garmin owner's manual: Body Battery).
Sourced figures
Every number in this guide comes from the source linked beside it. Each study result applies to that study's devices, participants and protocol only.
Garmin Forerunner 235 heart rate vs ECG during exercise: Lin's concordance 0.81 (Polar H7 chest strap 0.996).
Gillinov et al. (2017), Medicine & Science in Sports & Exercise
Garmin Forerunner 245 vs polysomnography: 50% epoch agreement for sleep stage + wake (κ 0.25); 89% for sleep vs wake (κ 0.35).
Miller, Sargent & Roach (2022), Sensors · Garmin Forerunner 245 research record
Garmin Vivosmart 4 SpO2 root mean squared error in people with COPD: 3.3% at rest, 6.1% after sit-to-stand.
Støve et al. (2023), Respiratory Care · Garmin Vivosmart 4 research record
Garmin Fenix 5S and Vivosmart 3 performed worse than actigraphy for sleep/wake classification against polysomnography.
What published studies show
Results quoted from 18 published validation studies, each against a clinical reference. A result applies to the model and protocol tested, not to every model the brand sells. From the wearable accuracy database (v1.0.0).
Heart rate at rest1 study
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Vivoactive 4 | ρc = 0.9998Lin's concordance correlation | ECG | n = 263, 30-min standardised recording | Theurl et al. (2023)Independent |
- Garmin Vivoactive 4ρc = 0.9998
Lin's concordance correlation · vs ECG · n = 263, 30-min standardised recording
Theurl et al. (2023) Independent
Heart rate during exercise3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Vivosmart 5 | Skin pigmentation did not predict error (P = 0.29)Study finding (no single number) | ECG chest strap (Polar H7/ | n = 28, Rest, cycling, recovery | Mulholland et al. (2026)Independent |
| Garmin Fenix 5 | 2.9%–9.2% (range by intensity)Coefficient of variation | ECG chest strap (Polar H7/ | n = 25, Sitting, walking, running, sprints | Düking et al. (2020)Independent |
| Garmin Forerunner 235all exercise conditions | rc = 0.81Lin's concordance correlation | ECG | n = 50, Gillinov: treadmill, bike, elliptical | Gillinov et al. (2017)Funding not reported |
- Garmin Vivosmart 5Skin pigmentation did not predict error (P = 0.29)
Study finding (no single number) · vs ECG chest strap (Polar H7/H10) · n = 28, Rest, cycling, recovery
Mulholland et al. (2026) Independent
- Garmin Fenix 52.9%–9.2% (range by intensity)
Coefficient of variation · vs ECG chest strap (Polar H7/H10) · n = 25, Sitting, walking, running, sprints
Düking et al. (2020) Independent
- Garmin Forerunner 235rc = 0.81
Lin's concordance correlation, all exercise conditions · vs ECG · n = 50, Gillinov: treadmill, bike, elliptical
Gillinov et al. (2017) Funding not reported
Overnight heart rate1 study
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Forerunner 245 Music | ICC 0.41Intraclass correlation | ECG | n = 53, Overnight, sleep laboratory | Miller et al. (2022)Other maker funded |
| Garmin Forerunner 245 Music | 5.4 bpm (absolute bias)Mean absolute error | ECG | n = 53, Overnight, sleep laboratory | Miller et al. (2022)Other maker funded |
- Garmin Forerunner 245 MusicICC 0.41
Intraclass correlation · vs ECG · n = 53, Overnight, sleep laboratory
Miller et al. (2022) Other maker funded
- Garmin Forerunner 245 Music5.4 bpm (absolute bias)
Mean absolute error · vs ECG · n = 53, Overnight, sleep laboratory
Miller et al. (2022) Other maker funded
HRV (RMSSD)3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Fenix 6 | 10.52%Mean absolute percentage error | ECG | n = 13, Home, during sleep, 536 nights | Dial et al. (2025)Independent |
| Garmin Fenix 6 | 0.87Lin's concordance correlation | ECG | n = 13, Home, during sleep, 536 nights | Dial et al. (2025)Independent |
| Garmin Forerunner 245 Music | ICC 0.24Intraclass correlation | ECG | n = 53, Overnight, sleep laboratory | Miller et al. (2022)Other maker funded |
| Garmin Forerunner 245 Music | 33.1 ms (absolute bias)Mean absolute error (absolute bias) | ECG | n = 53, Overnight, sleep laboratory | Miller et al. (2022)Other maker funded |
| Garmin Vivoactive 4 | ρc = 0.66 (moderate)Lin's concordance correlation | ECG | n = 263, 30-min standardised recording | Theurl et al. (2023)Independent |
- Garmin Fenix 610.52%
Mean absolute percentage error · vs ECG · n = 13, Home, during sleep, 536 nights
Dial et al. (2025) Independent
- Garmin Fenix 60.87
Lin's concordance correlation · vs ECG · n = 13, Home, during sleep, 536 nights
Dial et al. (2025) Independent
- Garmin Forerunner 245 MusicICC 0.24
Intraclass correlation · vs ECG · n = 53, Overnight, sleep laboratory
Miller et al. (2022) Other maker funded
- Garmin Forerunner 245 Music33.1 ms (absolute bias)
Mean absolute error (absolute bias) · vs ECG · n = 53, Overnight, sleep laboratory
Miller et al. (2022) Other maker funded
- Garmin Vivoactive 4ρc = 0.66 (moderate)
Lin's concordance correlation · vs ECG · n = 263, 30-min standardised recording
Theurl et al. (2023) Independent
Sleep stages (4-stage)2 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Forerunner 245 Music | 50%Epoch-by-epoch agreement | Polysomnography (PSG) | n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together | Miller et al. (2022)Other maker funded |
| Garmin Forerunner 245 Music | κ = 0.25Cohen's kappa | Polysomnography (PSG) | n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together | Miller et al. (2022)Other maker funded |
| Garmin Vivosmart 4 | κ = 0.21Cohen's kappa | Polysomnography (PSG) | n = 25, Sleep laboratory, 1 night | Schyvens et al. (2025)Funding not reported |
Epoch-by-epoch agreement · vs Polysomnography (PSG) · n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together
Miller et al. (2022) Other maker funded
- Garmin Forerunner 245 Musicκ = 0.25
Cohen's kappa · vs Polysomnography (PSG) · n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together
Miller et al. (2022) Other maker funded
- Garmin Vivosmart 4κ = 0.21
Cohen's kappa · vs Polysomnography (PSG) · n = 25, Sleep laboratory, 1 night
Schyvens et al. (2025) Funding not reported
Sleep vs wake (2-stage)3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Vivosmart 4 | > 90% (all devices)Sensitivity | Polysomnography (PSG) | n = 62, Sleep laboratory, 1 night | Schyvens et al. (2025)Funding not reported |
| Garmin Fenix 5S | Worse than actigraphyStudy finding (no single number) | Polysomnography (PSG) | n = 34, Sleep laboratory, 3 nights incl. disrupted night | Chinoy et al. (2021)Funding not reported |
| Garmin Vivosmart 3 | Worse than actigraphyStudy finding (no single number) | Polysomnography (PSG) | n = 34, Sleep laboratory, 3 nights incl. disrupted night | Chinoy et al. (2021)Funding not reported |
| Garmin Forerunner 245 Music | 89%Epoch-by-epoch agreement | Polysomnography (PSG) | n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together | Miller et al. (2022)Other maker funded |
| Garmin Forerunner 245 Music | κ = 0.35Cohen's kappa | Polysomnography (PSG) | n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together | Miller et al. (2022)Other maker funded |
- Garmin Vivosmart 4> 90% (all devices)
Sensitivity · vs Polysomnography (PSG) · n = 62, Sleep laboratory, 1 night
Schyvens et al. (2025) Funding not reported
- Garmin Fenix 5SWorse than actigraphy
Study finding (no single number) · vs Polysomnography (PSG) · n = 34, Sleep laboratory, 3 nights incl. disrupted night
Chinoy et al. (2021) Funding not reported
- Garmin Vivosmart 3Worse than actigraphy
Study finding (no single number) · vs Polysomnography (PSG) · n = 34, Sleep laboratory, 3 nights incl. disrupted night
Chinoy et al. (2021) Funding not reported
Epoch-by-epoch agreement · vs Polysomnography (PSG) · n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together
Miller et al. (2022) Other maker funded
- Garmin Forerunner 245 Musicκ = 0.35
Cohen's kappa · vs Polysomnography (PSG) · n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together
Miller et al. (2022) Other maker funded
Total sleep time1 study
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Forerunner 945 | MAE 84.63 min (overestimate)Mean absolute error | Polysomnography (PSG) | n = 49, 1 night PSG + MSLT | Budig et al. (2022)Independent |
- Garmin Forerunner 945MAE 84.63 min (overestimate)
Mean absolute error · vs Polysomnography (PSG) · n = 49, 1 night PSG + MSLT
Budig et al. (2022) Independent
Blood oxygen (SpO2)5 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Vivosmart 4 | 3.3% (rest)Root-mean-square error | Medical-grade pulse oximeter | n = 36, Rest, COPD outpatients | Støve et al. (2023)Funding not reported |
| Garmin Venu 2S | 5.8% (RMSE 6.7%)Mean absolute error | Medical-grade pulse oximeter | n = 49, Spot readings, with and without chronic pulmonary disease | Jiang et al. (2023)Independent |
| Garmin Venu 2S | 6.7%Root-mean-square error | Medical-grade pulse oximeter | n = 49, Spot readings, with and without chronic pulmonary disease | Jiang et al. (2023)Independent |
| Garmin Fenix 5X Plus | 9.77% (ICC 0.549)Mean absolute percentage error | Arterial blood gas (SaO2) | n = 13, High altitude 4559 m | Schiefer et al. (2021)Independent |
| Garmin Fenix 5X Plus | +3.3% at 12,000 ft (LoA −1.9 to 8.6%)Mean bias (signed) | Medical-grade pulse oximeter | n = 23, Normobaric hypoxia, rest, 900–12,000 ft | Lauterbach et al. (2021)Funding not reported |
| Garmin Fenix 6 | 4.29% (CCC 0.10)Mean absolute percentage error | Medical-grade pulse oximeter | n = 22, Normoxic and hypoxic conditions | Carrier et al. (2025)Independent |
- Garmin Vivosmart 43.3% (rest)
Root-mean-square error · vs Medical-grade pulse oximeter · n = 36, Rest, COPD outpatients
Støve et al. (2023) Funding not reported
- Garmin Venu 2S5.8% (RMSE 6.7%)
Mean absolute error · vs Medical-grade pulse oximeter · n = 49, Spot readings, with and without chronic pulmonary disease
Jiang et al. (2023) Independent
- Garmin Venu 2S6.7%
Root-mean-square error · vs Medical-grade pulse oximeter · n = 49, Spot readings, with and without chronic pulmonary disease
Jiang et al. (2023) Independent
- Garmin Fenix 5X Plus9.77% (ICC 0.549)
Mean absolute percentage error · vs Arterial blood gas (SaO2) · n = 13, High altitude 4559 m
Schiefer et al. (2021) Independent
- Garmin Fenix 5X Plus+3.3% at 12,000 ft (LoA −1.9 to 8.6%)
Mean bias (signed) · vs Medical-grade pulse oximeter · n = 23, Normobaric hypoxia, rest, 900–12,000 ft
Lauterbach et al. (2021) Funding not reported
- Garmin Fenix 64.29% (CCC 0.10)
Mean absolute percentage error · vs Medical-grade pulse oximeter · n = 22, Normoxic and hypoxic conditions
Carrier et al. (2025) Independent
VO2max estimate3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Forerunner 245 | 7.9% / 7.2% (two runs)Mean absolute percentage error | Indirect calorimetry | n = 35, Treadmill ramp test | Engel et al. (2026)Funding not reported |
| Garmin Fenix 6 | 7.05% (CCC 0.73)Mean absolute percentage error | Indirect calorimetry | n = 19, Graded exercise test and outdoor run | Carrier et al. (2025)Independent |
| Garmin Forerunner 920XT | 7.3%Mean absolute percentage error | Indirect calorimetry | n = 24, Lab | Passler et al. (2019)Independent |
- Garmin Forerunner 2457.9% / 7.2% (two runs)
Mean absolute percentage error · vs Indirect calorimetry · n = 35, Treadmill ramp test
Engel et al. (2026) Funding not reported
- Garmin Fenix 67.05% (CCC 0.73)
Mean absolute percentage error · vs Indirect calorimetry · n = 19, Graded exercise test and outdoor run
Carrier et al. (2025) Independent
- Garmin Forerunner 920XT7.3%
Mean absolute percentage error · vs Indirect calorimetry · n = 24, Lab
Passler et al. (2019) Independent
Energy expenditure (calories)3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Fenix 5 | 15.9%–34.5% (range by intensity)Coefficient of variation | Indirect calorimetry | n = 25, Sitting, walking, running, sprints | Düking et al. (2020)Independent |
| Garmin Forerunner 955physical activity energy expenditure, 10 min | +68.61 kcalMean bias (signed) | Indirect calorimetry | n = 51, 10-min recumbent cycling intervals | Kostrna et al. (2026)Independent |
| Garmin Fenix 6walking | 32.0% walk / 21.8% runMean absolute percentage error | Indirect calorimetry | n = 20, Outdoor 2-km walk (6 km/ | Le et al. (2022)Independent |
- Garmin Fenix 515.9%–34.5% (range by intensity)
Coefficient of variation · vs Indirect calorimetry · n = 25, Sitting, walking, running, sprints
Düking et al. (2020) Independent
- Garmin Forerunner 955+68.61 kcal
Mean bias (signed), physical activity energy expenditure, 10 min · vs Indirect calorimetry · n = 51, 10-min recumbent cycling intervals
Kostrna et al. (2026) Independent
- Garmin Fenix 632.0% walk / 21.8% run
Mean absolute percentage error, walking · vs Indirect calorimetry · n = 20, Outdoor 2-km walk (6 km/h) and run (10 km/h)
Le et al. (2022) Independent
Garmin Elevate v5 Optical Sensor: PPG Specs and Accuracy Comparisons
Garmin vs Apple Watch: Heart Rate Accuracy from Published Studies
In the studies that tested both brands, Apple Watch agreed more closely with ECG for exercise heart rate and overnight heart rate. Series 10 and Fenix 8 were not the models tested.
View Comparison →Apple Watch Ultra 2 vs Garmin Fenix 8: Specs Guide
Choose the Garmin Fenix 8 if battery life, built-in mapping, and training tools come first. Choose the Apple Watch Ultra 2 if you use an iPhone and value tighter Apple integration, cellular connectivity, and a brighter specified display. Both offer optical heart-rate sensing, multi-band positioning, ECG support in eligible regions, and a 40 m recreational dive rating. This comparison uses the 49 mm Ultra 2 and 47 mm Fenix 8 AMOLED as the clearest like-for-like models.
View Comparison →Polar vs Garmin: Overnight Heart Rate Accuracy from a Published Study
In Miller et al. (2022, 53 adults), Polar Vantage V tracked overnight heart rate more closely than Garmin Forerunner 245 (ICC 0.93 vs 0.41). Sleep staging was similar. Those are older models than the watches named here.
View Comparison →Forerunner 965 vs Fenix 8: Battery, Water Rating and ECG
Both watches run Garmin's training and recovery features, including HRV Status. Per Garmin's manuals, the Forerunner 965 lasts up to 23 days in smartwatch mode and is rated 5 ATM; the Fenix 8 (47 mm AMOLED) lasts up to 16 days with the gesture display and is rated 10 ATM plus 40 m recreational diving. Garmin names the Fenix 8 among watches with its ECG App. No study has compared their heart-rate accuracy.
View Comparison →WHOOP vs Garmin: Sleep and Heart Rate Accuracy from a Published Study
In Miller et al. (2022, 53 adults), WHOOP 3.0 agreed more closely with ECG overnight (HR ICC 0.99 vs 0.41) and with polysomnography sleep stages (60% vs 50%) than the Garmin Forerunner 245. WHOOP supplied raw data and funds the lab.
View Comparison →Fitbit vs Garmin: Heart Rate Accuracy from Published Studies
Older-model studies give mixed results. During exercise, the Garmin Forerunner 235 agreed more closely with ECG than the Fitbit Blaze (concordance 0.81 vs 0.67; Gillinov 2017). For sleep, Fitbit Alta HR performed as well as or better than actigraphy while Garmin Fenix 5S and Vivosmart 3 did worse (Chinoy 2021), and Fitbit Sense and Charge 5 (κ 0.42/0.41) beat Garmin Vivosmart 4 (κ 0.21) in Schyvens 2025.
View Comparison →Amazfit vs Garmin: Budget vs Premium PPG Sensor Technology
Amazfit's T-Rex Ultra lists up to 20 days typical battery, 10 ATM water resistance and a BioTracker PPG sensor with blood-oxygen support. Garmin's Forerunner 265 lists up to 13 days and 5 ATM; the Fenix 8 (47 mm AMOLED) up to 16 days and 10 ATM plus 40 m diving. ChatPPG has not verified a peer-reviewed accuracy study of the T-Rex Ultra; Garmin's evidence comes from older models.
View Comparison →COROS vs Garmin: PPG Sensor and Training Platform Compared
COROS quotes 36 days of regular use for the VERTIX 2S (10 ATM) and 15 days for the PACE 3 (5 ATM). Garmin quotes up to 13 days for the Forerunner 265 (5 ATM) and up to 16 days for the Fenix 8 47 mm AMOLED (10 ATM plus 40 m diving). ChatPPG has not verified a peer-reviewed accuracy study of either COROS model, so this page does not rank heart-rate accuracy.
View Comparison →Suunto vs Garmin: PPG Sensor Accuracy for Outdoor Athletes
Suunto Race quotes up to 16 days of daily use with heart rate on (26 days with it off), 100 m water resistance and a blood-oxygen widget, including altitude acclimation. Garmin quotes up to 16 days for the Fenix 8 47 mm AMOLED and up to 36 days for the Enduro 3 (90 days with solar). Both brands offer SpO2. ChatPPG has not verified a peer-reviewed accuracy study of the Suunto Race.
View Comparison →Samsung Galaxy Watch vs Garmin: Sensors Compared
Samsung's Galaxy Watch7 and Watch Ultra offer an FDA-cleared ECG app and cuffless blood pressure estimates that need cuff calibration every 28 days; they pair only with Android. Garmin's Venu 3 and Fenix 8 offer an ECG App in eligible regions and battery measured in weeks. No study compares current Samsung and Garmin heart-rate accuracy.
View Comparison →Research records
Device records collect datasets, papers, and the sourced figures on this page.
Also named in this guide: Polar H7
Frequently Asked Questions
How does Garmin Elevate v5 compare to Elevate v4?
Garmin describes the newer sensor as an updated optical heart-rate design, and compatible Elevate v5 watches can also support features such as ECG. Garmin does not publish a sampling-rate or accuracy comparison between the two generations.
Is Garmin HRV accurate for clinical use?
Garmin HRV Status is a wellness trend built from overnight wrist readings and a personal baseline. Garmin does not publish an ECG-referenced HRV accuracy figure for it. For clinical HRV work, an ECG reference such as a chest-strap ECG or Holter remains the standard.
Does Garmin SpO2 work during exercise?
Garmin advises wearing the watch snugly above the wrist bone and holding the arm at heart level while a Pulse Ox reading is taken (Garmin owner's manual: Pulse Ox). In one COPD study, Vivosmart 4 SpO2 error was 3.3% at rest and 6.1% after a sit-to-stand test (Støve et al., 2023).
Sources
- Gillinov et al. (2017). Variable Accuracy of Wearable Heart Rate Monitors during Aerobic Exercise. Medicine & Science in Sports & Exercise. doi:10.1249/MSS.0000000000001284
- Miller, Sargent & Roach (2022). A Validation of Six Wearable Devices for Estimating Sleep, Heart Rate and Heart Rate Variability in Healthy Adults. Sensors. doi:10.3390/s22166317
- Støve et al. (2023). Assessment of Noninvasive Oxygen Saturation in Patients With COPD During Pulmonary Rehabilitation: Smartwatch versus Pulse Oximeter. Respiratory Care. doi:10.4187/respcare.10760
- Chinoy et al. (2021). Performance of seven consumer sleep-tracking devices compared with polysomnography. Sleep. doi:10.1093/sleep/zsaa291
- Garmin. Understanding the HRV Status on Your Garmin Smartwatch
- Garmin. Instinct 2 Series Owner's Manual: Body Battery
- Garmin. Venu 2 Series Owner's Manual: Tips for Erratic Pulse Oximeter Data