Device comparisons
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.
Devices
Suunto Race in all black: product photograph from Suunto. Garmin fēnix 8 47 mm AMOLED, slate gray case with a black silicone band (part 010-02904-00): product photograph from Garmin.
At a glance
This page does not list head-to-head accuracy numbers, so the scoreboard shows hardware differences only.
| Specification | Suunto Race | Garmin (Fenix 8 / Enduro 3) |
|---|---|---|
| Battery LifeDiffers | Up to 16 days (HR on); 26 days (HR off) | Up to 16 days (Fenix 8 47 mm AMOLED); 36 days / 90 days solar (Enduro 3) |
| Water ResistanceDiffers | 100 m | 10 ATM (Fenix 8, Enduro 3); 40 m dive (Fenix 8) |
| SpO2Differs | Yes (blood oxygen widget; not for medical use) | Pulse Ox |
Primary rows only. The study tables further down list more results from the accuracy database.
Hardware specs
| Specification | Suunto Race | Garmin (Fenix 8 / Enduro 3) |
|---|---|---|
| Battery LifeDiffers | Up to 16 days (HR on); 26 days (HR off) | Up to 16 days (Fenix 8 47 mm AMOLED); 36 days / 90 days solar (Enduro 3) |
| Water ResistanceDiffers | 100 m | 10 ATM (Fenix 8, Enduro 3); 40 m dive (Fenix 8) |
| SpO2Differs | Yes (blood oxygen widget; not for medical use) | Pulse Ox |
Hardware only. Study results are not repeated in this table. Differs marks values that are not the same. An em dash means this page did not publish that figure.
Specs verified on October 17, 2026: Suunto Race specifications, Garmin Fenix 8 owner's manual: battery information, Garmin Fenix 8 owner's manual: specifications, Garmin Enduro 3 owner's manual: battery information, Garmin Enduro 3 owner's manual: specifications, Garmin: ECG App expands to Australia and the EU (Venu 3, Fenix 8).
Pros and cons
Suunto Race
Pros
- Up to 16 days daily use with heart rate on
- Waterproof to 100 m
- Blood oxygen, including altitude acclimation
Cons
- No peer-reviewed validation verified by ChatPPG
- No ECG
Garmin (Fenix 8 / Enduro 3)
Pros
- Enduro 3: up to 36 days smartwatch (90 days solar)
- Fenix 8: ECG App and 40 m dive rating
- Pulse Ox and HRV Status
Cons
- Fenix 8 47 mm AMOLED quotes up to 16 days, similar to Race
- Older-model Garmin results mixed in independent studies
What published studies show
One table per metric. These rows come from the accuracy database and are not repeated as a second card list. 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 |
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 |
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 |
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 |
More results (1)
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Vivoactive 4 | ρc = 0.66 (moderate)Lin's concordance correlation | 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 |
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 |
More results (1)
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| 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 |
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 |
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 |
More results (2)
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| 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 |
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 |
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 |
Verdict
Both brands offer blood oxygen and 100 m-class water ratings. Garmin's Enduro 3 quotes the longest battery and the Fenix 8 adds ECG and dive features. No study compares Suunto and Garmin accuracy.
Frequently asked questions
Does Suunto have SpO2 for altitude monitoring?
Yes. Suunto Race has a blood-oxygen widget and lists altitude acclimation with blood oxygen; Suunto says readings are not for medical use.
Is Suunto heart rate as accurate as Garmin?
No head-to-head study exists, and ChatPPG has not verified a peer-reviewed validation of the Suunto Race.