How accurate is the Apple Watch heart rate monitor?

Factual Questions
1

I’ve been looking for some technical specs and comparisons between it and chest-based monitors, but I couldn’t find anything. Anyone know where that information might reside?

Thanks.

2

I doubt it’s been published yet, as the watch itself won’t be sold until early next year.

3

I don’t think that tech specs are going to help you very much here. It will be difficult to get specs on how sweat and movement interfere with the heart rate monitor. I have read reviews of similar samsung watches and the reviewers said that the heart rate monitor did not work very well when exercising. Also I have read that the heart rate monitor on the apple watch is not continuous like with exercise equipment but instead has to be commanded to take indiviual measurements. I think you had best wait for reviews from people testing it in situation similar to the ones you are concerned about.

4

Given there are extant Apple Watches outside Apple, and the real thing won’t begin production until next year, I doubt there is any comparative data.

OTOH, we know the Apple Watch uses an IR LED and detector pair to monitor pulse. The technology is known to be good, and there is no intrinsic reason to think it would not be perfectly accurate. By perfectly accurate I mean - will not drop a beat or add a beat. In reality the system will be tuned so that it operates to an acceptable level of reliability whilst minimising battery draw for the IR LED. This means they tune the signal to noise ratio for acceptable performance. What design choices were made, we don’t know. LED brightness may well be under software control, and may even be in a feedback loop that auto tunes the signal to noise. The ability of the software to filter the results (essentially creating a software PLL) can yield a very robust beat frequency estimator.

Answer- we don’t know, but there is no good reason to think it won’t deliver perfectly accurate results. But no good reason to think it will be so either.

5

Thanks for the answers. Does anyone know if there is someone else out there measuring heart rate with the identical technology?

6

The Samsung gear fit measures heart rate in a similar way to how the apple watch will do it. It was the watch I had in mind when I said reviews of the heart rate monitor said it was problematic.