Table 1 Biometric features available in commonly used smartwatch, wrist-band and ring (Apple, Fitbit, Garmin, Oura, Polar, Samsung, Withings and Whoop) wearables
Apple | Fitbit | Garmin | Oura | Polar | Samsung | Withings | Whoop | |
|---|---|---|---|---|---|---|---|---|
Health metrics | ||||||||
Resting HR | Every 5 mins | Every 1 min | Every 15 sec | Every 5 mins | Every 1 sec | Every 5 mins | Every 10 mins | Every 1 sec |
HR during activity | Every 1 sec | Every 1 sec | Every 1 sec | Every 1 sec | Every 1 sec | Every 1 sec | Every 1 sec | Every 1 sec |
HR sensor | PPG & ECG | PPG | PPG | PPG | PPG | PPG | PPG | PPG |
HRV | ✓ SDNN | ✓ RMSSD | ✓ RMSSD SDNN * selected models | ✓ RMSSD | ✓ RMSSD | ✓ SDNN | ✓ SDNN * selected models | ✓ RMSSD |
HRV sensor | PPG & ECG | PPG | PPG | PPG | PPG | PPG | PPG & ECG | PPG |
HRV measurements | Sleep & at rest | Sleep | Sleep & Health Snapshot (informs body battery & overnight recovery data) | Sleep | Sleep & training | Sleep & stress tracking | Sleep | Sleep (informs baseline recovery, strain, overall readiness score) |
ECG | ✓ * Series 4 & later models | ✓ * Sense & Charge 5 | ✓ * Venu2+ onwards, Epix Pro (Gen 2), Fenix 7 pro onwards, quatix 7 Pro, tactix 7, D2 Mach 1 Pro, Enduro 3 | × | ✓ * Grit X2 Pro, Vantage V3 | ✓ * Galaxy Watch 3, Galaxy Watch Active 2 & later models | ✓ * ScanWatch & Move ECG | × |
ECG recording duration | 30 s on demand | 30 s on demand | 30 s on demand | n/a | 30 s on demand | 30 s on demand | 30 s on demand | n/a |
ECG reporting | Sinus rhythm Atrial fibrillation Low or high HR ( < 50 or >120 bpm) Inconclusive Poor recording | Sinus rhythm Atrial Fibrillation | Sinus rhythm Atrial Fibrillation | n/a | Average HR HRV Beat to beat interval Pulse arrival time Orthostatic test | Sinus rhythm Atrial Fibrillation | Sinus rhythm Possible Atrial Fibrillation | n/a |
FDA clearance for AF detection | ✓ ECG & PPG | ✓ ECG & PPG | × | × | × | ✓ ECG | ✓ ECG | × |
SpO2 | ✓ Blood Oxygen * Series 6 & later models | ✓ SpO2 Sensor / Estimated Oxygen Variation * Charge 4 & later models, Sense & Versa series | ✓ Pulse Ox (On demand or continuously) | ✓ Blood oxygen sensing * Gen 3 | ✓ SpO2 * Vantage | ✓ Blood oxygen * Galaxy Watch 3, Galaxy Watch Active 2 & later models | ✓ Oxygen saturation On demand and sleep tracking | ✓ Blood oxygen saturation * 4.0 |
Respiratory rate | ✓ Respiratory rate * Series 4 & later models | ✓ Breathing rate * Charge 4 & later models, Sense & Versa series | ✓ Respiration rate * Venu, Fenix, Forerunner series | ✓ Respiratory rate * Gen 2 & onwards | ✓ Respiration rate * Vantage | ✓ Respiratory rate * Galaxy Watch 3 & onwards | ✓ Breathing disturbances | ✓ Respiratory rate * 3.0 onwards |
Respiratory rate measurements | Sleep | Sleep, rest & activity | Sleep, rest & activity | Readiness & sleep scores | Nightly recharge Serene guided breathing exercise | Sleep analysis | Irregular breathing patterns during sleep | Continuously |
Temperature | ✓ Wrist temperature * Series 8 & later models | ✓ Skin temperature variation * Sense, Versa 3 & Charge 5 | ✓ Skin temperature * Venu3 onwards, Epix Pro (Gen 2), Fenix 7 pro onwards, quatix 7 Pro, tactix 7, D2 Mach 1 Pro, Enduro 3 | ✓ Body temperature * Gen 3 | ✓ Nightly skin temperature | ✓ Skin temperature * Galaxy Watch 5 | ✓ Body temperature * Scanwatch 2 | ✓ Skin temperature * 3.0 onwards |
Stress / readiness score | × | ✓ Stress management score / daily readiness score | ✓ Stress tracking / body battery | ✓ Readiness score / daytime stress / resilience | ✓ Nightly recharge | ✓ Stress monitoring | ✓ Stress level | ✓ Stress score / day strain / recovery |
Stress/ readiness score based on | n/a | EDA, HRV & sleep | HRV, sleep & activity | HRV, sleep, recovery metrics | HRV & sleep | HRV & other biometrics | HRV | HRV & HR data |
Blood pressure | × Compatible with external BP cuffs | × | × | × | × | ✓ * requires periodic calibration with a traditional BP cuff * region dependent * Galaxy Watch 3, Galaxy Watch Active 2 & later models | × Compatible with external BP cuffs (Withings BPM Connect) | × |
Body composition | × | × * From compatible smart scales (Fitbit Aria) | × * From compatible smart scales (Garmin Index Scale) | × | × | ✓ Body fat %, skeletal muscle, basal metabolic rate & body water. * Galaxy Watch 4 & onwards | × * From compatible smart scales (Withings Body+ and Body Cardio) | × |
Energy expenditure | ✓ Active & total calories | ✓ Active & resting calories | ✓ Total calories | ✓ Calories burned | ✓ Total calories burned & calorie tracking for workouts | ✓ Calories burned during activities & during the day | ✓ Calories burned | ✓ Calories burned |
Women’s health | ✓ Digital diary with predictions | ✓ Digital diary with predictions | ✓ Digital diary with predictions | ✓ Digital diary with predictions | × | ✓ Digital diary with predictions | ✓ Digital diary | ✓ Digital diary |
Activity metrics | ||||||||
Step count | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Distance | ✓ via step count & GPS | ✓ via step count & GPS | ✓ via step count & GPS | ✓ via step count | ✓ via step count & GPS | ✓ via step count & GPS | ✓ via step count & GPS | ✓ via activity data |
Built in GPS | ✓ most models | ✓ most models | ✓ most models | × location access can be granted via mobile phone app | ✓ most models | ✓ most models | ✓ most models | × location access can be granted via mobile phone app |
Floors climbed | ✓ 3 m (10 feet) | ✓ 3 m (10 feet) | ✓ 3 m (10 feet) | × | ✓ * Vantage & Grit series | ✓ 3 m (10 feet) | × | × |
Auto. activity recognition | ✓ | ✓ SmartTrack | ✓ Auto Activity Start | × | ✓ Automatic Training Detection | ✓ Auto Detect Activity | ✓ Automatic Workout Detection | ✓ |
CRF | ✓ VO2max (Cardio Fitness Level) | ✓ Cardio Fitness Score | ✓ VO2max | ✓ Cardio Capacity | ✓ Fitness test for VO2max | ✓ VO2max | ✓ Cardio Fitness | ✓ Strain Score |
CRF estimate based on | HR & activity data from outdoor walking or running | HR & activity data | HR & activity data from outdoor activities (walking, running, cycling) | Anthropometric data & walking test | HR during specific activities | During specific workouts | HR & activity data | Workout intensity (indirect cardiovascular fitness) |
CRF units | ml/kg/min | ml/kg/min | ml/kg/min | ml/kg/min | ml/kg/min | ml/kg/min | ml/kg/min | Score |
Sleep | ||||||||
Time spent asleep | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Sleep stages | ✓ REM, Core & Deep | ✓ Light, deep & REM | ✓ Light, deep & REM | ✓ Light, deep & REM | ✓ Light, deep & REM | ✓ Light, deep & REM | ✓ Light, deep & REM | ✓ Light, deep & REM |
Technical specifications | ||||||||
Bluetooth connectivity | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
iOS requirements | iPhone 6 s or later with iOS 14 or later | iOS 14 or later | iOS 12 or later | iOS 12 or later | iOS 12 or later | May not support all features with iOS | iOS 12 or later | iOS 12 or later |
Android requirements | Not compatible | Android 8.0 or later | Android 6.0 or later | Android 8.0 or later | Android 6.0 or later | Android 6.0 or later | Android 6.0 or later | Android 6.0 or later |
Battery life | ~3 days | ~5 days | ~5 days | 4–7 days | 5–14 days | 1–2 days | 30 days | 4–5 days |
