Originally Posted by caloso

I have used a HRM for at least 20 years, but since I got a power meter (10 years ago?) I mostly use HR data for aerobic decoupling and to gauge fatigue. I never look at it in the moment.

Re the 220-age formula, I agree with you. It makes no sense. My understanding is that it originated out of a study of maximum heart rates of untrained persons. When they graphed the scattershot data of MaxHR against age, someone noticed you could fit a line that worked out to 220-age. Interesting enough for what it is: it shows a trend of decreasing MaxHR as people age. It has no predictive value for any one particular person. Even less so for athletes.

Somehow, it has gained this status of a medical truth, but it makes no sense to apply it to an individual. I mean you could probably draw a similar line of shoe size against height, but when you go to a shoe store, would you choose your size base on a chart? No! You'd measure your foot.

So, I've always just used my highest observed HR for the prior 12 months. In my case that's 191, which I saw at the end of sprint on the local Saturday group ride. on a hot day last summer. I'm 55, so that's 26 pts above (116%) what the formula would predict.