Originally Posted by brianappleby
why can't HR be a (relatively) accurate indicator of effort?
I was thinkng about this yesterday during a low intensity ride...
I can hold:
160bpm and 260 watts at 85 rpm
or:
160bpm and 220 watts at 100 rpm
of course i could just pedal a bit harder at 100 rpm and bring the power back up, but then my HR would increase, so if i were wanting to go faster, shouldn't I just pedal harder and increase the HR at 85rpm?
So can someone please explain why 85rpm wouldn't be my ideal cadence period, and that anyone with access to a powertap couldn't do the same for themselves?
That's because HR is only measuring your heart/lungs. There's also your muscles, which has a different indicator. It's like comparing the tachometer vs. the speedometer in a car.
The "ideal" cadence comes down to your personal physique and power-output. In general the higher the power-output needed, the higher the RPM. Try putting out 400w for a while at two difference cadences and note how your legs feel as well.