Reliability of wrist heart rate monitors – BionicoldGuy

Today, wrist-based measurement devices can monitor our heart rate, which is very common today, including Fitbit, Garmin watches and Apple Watches. There are also devices that can promise more complex results, such as heart rate variability from Hoop. These devices then tell us insightful things about our recent workouts or full-day activities, how long should we recover before the next hard workout, or even our sleeping condition.

The problem is the accuracy of the data. All this information is based on suspiciousness. I noticed this first when I had a Fitbit. Based on my hard work, it is usually correct than I think. Now, so is my Garmin watch. I could just warm up and it would tell me my heart rate in the 130s and I knew it wasn’t right because I was really upset and gasping. I’ve tested this recently. I happen to have a polar H10 heart rate strap. and a separate device (my Garmin bike computer). So on the same trip I made sure my watch was paired with the belt and only wrist data was available for heart rate. My bike computer is paired with a belt, so it’s a chest-based measurement. In such a comparison, we expect the measurements of the chest to be more accurate, but I was different from the two. The following shows a three-hour ride. The maximum heart rate measured by the wrist was 41 hits, two highs, and it was suspicious when I just heated up. There are other places in the chart where the wrist results are incorrect.

I’ve been reading about the best training techniques based on heart rate, and all of this sounds scientific. But I now know that my data based on this is not credible (I usually just use wrist-based data as this is an extra step to wearing a belt). In the future, when I really want to check my heart rate, I will make sure to use the strap. I will also feel more trust in my exercise (perceived level of fatigue).