The most capable multi-sensor wristwatch on the market. Strong at ECG, everyday health nudges, GPS accuracy, and app ecosystem — weaker for high-fidelity HRV research than dedicated rings and straps.
The everyday-carry answer for iPhone users who want one device to cover everything except deep sleep research.
watchOS fuses PPG, ECG, temperature and IMU streams with GPS to generate health, activity and workout metrics. Health data flows into Apple Health and is available to third-party apps via HealthKit.
GPS and workout HR accuracy are excellent. ECG rhythm classification is FDA-cleared for atrial fibrillation. HRV is sampled sparsely — trend only, not intra-day.
Apple Health, HealthKit, Fitness+, Strava, Zwift, Training Peaks and thousands of third-party apps. Data export via Apple Health XML.
Health data is end-to-end encrypted when iCloud Advanced Data Protection is enabled. Local processing on-device where possible.
