Fenix automatic calculation of Max HR greatly skewed by one days odd data

I set my Max HR at 170. Recently i noticed that it is now at 194. Looking back at activities, I can figure out when it was raised. One day i took a walk and something spurious happened with HR and it recorded Max HR for that walk of 241 (clearly erroneous). And that was when Fenix raised my Max HR to 194 from 170.

This raises a few questions.

1. Does anybody know exactly how Fenix calculates Max HR. Clearly it is not "the max its ever observed" (or else it would have been 241).

2. Does anybody know if the calories burned calculated for an activity will be different assuming the same observed activity data, but if the specified Max HR is different?

2. Can i just delete that day's activity and then Fenix would re-calculate Max HR based on remaining data (and presumably go back to what it was?). I don't necessarily want to turn automatic detection off, but yet i don't want this one days data to skew the value so much.

3. Is there any way for past activities i can get them re-calculated based on a new entered Max HR, or does it just go forward in time from the moment i re-enter it?

Thanks if you can help me out with those questions about Max HR!

0 mcalista over 6 years ago

1. It normally takes the highest observed, even if that is only held for a few seconds, but I'm not sure what filters the algorithm might have to reject obviously unfeasible numbers (such as 241), or short spikes that are unaccompanied by a gradual ramp-up of HR as they should be with a genuine maximum.
2. Yes. Zones and the like are typically calculated as a % of HRMax, and this will affect calorie calculation.
3. No, it will not recalculate past activities. Just enter a new maxHR manually, and going forward it will use that until it autodetects a higher maxHR.

HRMax is a number that declines gradually with age, but doesn't really change with fitness. And most people don't go above 96-98% of maxHR even in a really hard workout. As such, I think that HR autodetect not a particularly useful concept (although it is slightly better than using the age-based default). Personally, I leave autodetect off, and just review activities that have involved genuinely maximal efforts - if they have a higher maxHR, then I'll enter that manually.

0 TomCon over 6 years ago

Thanks much! I think i'll do what you suggest and turn auto-detect off. And thanks for clarifying that manual entry will reset back to old value.