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 · 7h ago
Whoever wrote this article needs to update their AI model
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.