The highest HR I’ve ever recorded is 184bpm - this was recorded while running (1 mile intervals). I’ve never come close to this HR while cycling. In fact the highest HR I’ve ever recorded while cycling is 174bpm, while doing a 10 mile TT (was fully spent!). My understanding of this is that running uses more muscles, so requires a higher HR.
Based on this all my HR zones are set based on my max HR being 184bpm (max running HR).
My calculated aerobic threshold (that I try not to exceed on easy days) is 142 bpm (77% of max HR).
If my HR zones were calculated based on the max HR I’d ever recorded on a bike, the zones would look pretty different. I’d need to ride quite a bit easier than I currently do to keep in the lower zones.
This got me thinking about cyclists setting zones based on max HR. If a cyclist has only tested their max HR based on cycling, is that actually even close to their true max HR?