
Units that monitor our coronary heart charges based mostly on a measurement on the wrist are fairly prevalent these days, together with Fitbit, Garmin watches, and Apple Watches. There are additionally gadgets that promise extra refined outcomes similar to coronary heart fee variability from Whoop. These gadgets then inform us insightful issues about our current exercises or our exercise all through the day, how lengthy we should always get better earlier than our subsequent arduous exercise, and even how nicely we’re sleeping.
The difficulty is that the accuracy of the info all this data is predicated on is suspect. I first observed this again once I had a Fitbit. It might usually learn larger than I suspected was right, based mostly on how arduous I felt I used to be working. The identical is now true of my Garmin watch. I will be simply warming up, and it’ll inform me my coronary heart fee is within the 130’s, which I do know can’t be true as a result of I’d actually be huffing and puffing. I not too long ago put it to a check. I occur to even have a Polar H10 coronary heart fee strap. And a separate system (my Garmin bike laptop). So on the identical trip, I made certain my watch was not paired to the strap, and solely had wrist information accessible for coronary heart fee. My bike laptop was paired to the strap so it was a chest-based measurement. In such a comparability, we count on the chest measurement to be extra correct, however I used to be blown away how a lot the 2 differed. The 2 charts from a three-hour trip are proven under. The max coronary heart fee from the wrist measurement was 41 beats two excessive, and suspiciously confirmed up once I was simply warming up. There are numerous different locations within the charts the place the wrist outcomes are simply not proper.


I had been studying up on optimum coaching strategies based mostly on coronary heart fee, all of which sound fairly scientific. However I now know that the info I used to be basing this on was untrustworthy (I often simply use wrist-based as a result of it’s an additional step to placed on the strap). Sooner or later I’ll make sure that I take advantage of the strap once I actually need to examine coronary heart fee. I may even put extra belief in how my exercise feels (perceived stage of exertion).