Hi there, I have been noticing that my heart rate seems to be fundamentally different between biking and running.
On runs, even at long race-pace efforts, my heart rate average will hover somewhere between 160-170bpm. And I can stay at this level of intensity for 90-120min. On the other hand, on my bike rides I am hard pressed to push my heart rate up to 160 bpm for anything other than high-intensity efforts of a few minutes (5 min or less). Anything beyond that and my thighs start burning to the point that I have to slow down.
I’m wondering if this means that my overall aerobic capacity and with it the oxygen flow driven by the heart rate is really not the limiting factor on the bike? Would this suggest that I should focus more on high-intensity training for shorter intervals to increase overall power output/FTP and focus a little less on longer/endurance rides?