Most smartwatches have two heart rate sensors: ECG (electrocardiogram) and PPG (optical heart rate sensor).
In the US, ECGs are regulated by the FDA as a class II medical device. So anything sold on the market has gone through reasonable accuracy testing.
PPGs are unregulated, but there's a decent amount of research on their accuracy. For example, the Apple Watch's heart rate monitor is accurate to 5bpm about 89-98% of the time (depending on whether you're standing, moving, etc).
A ton of health metrics are derived from these two sensors, plus the accelerometer --resting heart rate, VO2 Max, heart rate variability, cardio recovery, and so on.
SonOfKyuss•2h ago
Whoever wrote this article needs to update their AI model
brandonb•4h ago
In the US, ECGs are regulated by the FDA as a class II medical device. So anything sold on the market has gone through reasonable accuracy testing.
PPGs are unregulated, but there's a decent amount of research on their accuracy. For example, the Apple Watch's heart rate monitor is accurate to 5bpm about 89-98% of the time (depending on whether you're standing, moving, etc).
A ton of health metrics are derived from these two sensors, plus the accelerometer --resting heart rate, VO2 Max, heart rate variability, cardio recovery, and so on.