Garmin vs Apple Watch: PPG Sensor and Health Monitoring Compared
Garmin and Apple Watch represent two dominant philosophies in wearable health monitoring. Apple Watch prioritizes clinical health features with FDA-cleared ECG and irregular rhythm notifications, while Garmin focuses on sports performance with Firstbeat-powered HRV analytics. Both use multi-wavelength PPG sensors, but their algorithms, sampling strategies, and target use cases differ significantly.
Specifications Comparison
| Specification | Garmin (Fenix 8 / Forerunner 965) | Apple Watch (Series 10 / Ultra 2) |
|---|---|---|
| PPG Sensor | Elevate v5: multi-LED (green, red, IR), 4 photodiodes | Custom 4-cluster green LED, 4 photodiodes, red/IR pair |
| Sampling Rate | 25 Hz continuous, up to 100 Hz workout mode | Adaptive (every 5 min rest, continuous workout) |
| LED Wavelengths | Green 520 nm, Red 660 nm, IR 940 nm | Green 520 nm, Red 660 nm, IR 940 nm |
| Battery Life | 14–28 days (model dependent) | 18 hours (Series 10), 36 hours (Ultra 2) |
| Price | $499–$999 (one-time purchase) | $399–$799 (one-time purchase) |
| Weight | 47–53 g (Fenix 8), 53 g (FR 965) | 36–62 g (model dependent) |
| Water Resistance | 10 ATM (100 m) | WR50 (Series 10), 100 m / EN 13319 (Ultra 2) |
| SpO2 | Yes, resting only (Pulse Ox) | Yes, Blood Oxygen app (wellness feature) |
| HRV Metric | RMSSD (overnight, 21-day baseline) | SDNN (displayed), RMSSD (HealthKit export) |
Pros & Cons
Garmin (Fenix 8 / Forerunner 965)
Pros
- + Elevate v5 sensor with multi-wavelength PPG optimized for exercise accuracy
- + Exceptional battery life (up to 28 days) enables uninterrupted HRV trending
- + Firstbeat Analytics algorithms provide research-backed Body Battery and training metrics
- + No subscription required for full health and fitness feature access
Cons
- - SpO2 measurements limited to resting conditions only
- - No FDA-cleared health features (ECG, AFib detection)
- - Higher motion artifact errors during cycling and strength training than running
Apple Watch (Series 10 / Ultra 2)
Pros
- + FDA-cleared ECG and irregular rhythm notification for AFib detection
- + 4-photodiode PPG with advanced ambient light rejection algorithms
- + Comprehensive health ecosystem with crash detection and fall detection
- + Blood oxygen app with red and infrared LED measurement
Cons
- - Battery life of 18–36 hours requires daily or near-daily charging
- - SpO2 is wellness-only, not FDA-cleared as medical pulse oximeter
- - Health features locked to iPhone ecosystem
Verdict
Apple Watch is the superior choice for clinical health monitoring thanks to its FDA-cleared ECG and irregular rhythm notification, making it the best option for users concerned about cardiac health conditions like AFib. Garmin excels for endurance athletes and outdoor enthusiasts who need multi-week battery life, advanced training load analytics, and reliable HR during prolonged activities. From a PPG perspective, both sensors achieve comparable resting accuracy (2-4 bpm MAE), but Garmin's higher sustained sampling rate during workouts gives it an edge for exercise HR tracking.
Frequently Asked Questions
Which has better heart rate accuracy during exercise: Garmin or Apple Watch?
Both achieve similar accuracy during steady-state running (3-5 bpm MAE). Garmin's Elevate v5 performs slightly better during high-intensity intervals due to its 100 Hz workout sampling mode and Firstbeat motion artifact rejection. Apple Watch shows higher errors during cycling due to wrist flexion patterns.
Does Garmin or Apple Watch have better HRV tracking?
Both measure HRV overnight, but they report different metrics: Apple Watch shows SDNN in the Health app (with RMSSD available via HealthKit), while Garmin reports RMSSD with a 21-day rolling baseline. Garmin's continuous multi-day tracking without charging interruptions provides more complete HRV data.
Is Apple Watch or Garmin better for health monitoring?
Apple Watch is better for clinical health monitoring (ECG, AFib detection, fall detection, crash detection). Garmin is better for athletic performance monitoring (training load, Body Battery, VO2 max estimation). For PPG-based wellness metrics, both are comparable in accuracy.