I find the HR zones that are displaying on the App to be a little odd from my perspective. The range, in terms of bpm, of the various zones appears to vary dramatically.
For example for me:
-Z2 is from 112-138 bpm (16 beats)
-Z3 is from 139-151 bpm (12 beats)
-Z4 is from 152-159 bpm (7 beats)
-Z5 is from 160-191 bpm (31 beats), the upper range of which is way above my actual max HR, and if we take my actual Max HR (174) the range is 16 bpm
Why does the app calculate the Z4 range to have such a narrow window compared with the other zones?