To be more precise I've been following a HIIT on a cycloergometer and I found out this.


BPM: 105~120

Pedaling Rate: 60 rpm


BPM: 90~105

Pedaling Rate: 60 rpm

Basically my heart rate is diminished even though at the same resistance ( difficulty set on the c.e. ) I could exert the same rpms. What kind of adaptations are happening?

Take in mind that this measures are taken from the warm up phase before I begin my HIIT.


1 Answer 1


You've built muscle on the OUTSIDE of the bottom left ventricle from where the heart pumps blood into circulation.

Think of the left ventricle as a trampoline. The more blood goes in, the more it stretches (and builds muscle).

This adaptation allows the heart to fill the bottom left ventricle with more blood without having to rush it out. As your body can pump more blood in each beat, it doesn't have to beat as fast. Hence you can now get the same volume of blood and oxygen circulating in the body with 90-105 beats vs the previous 105-120 beats.

  • That's only half the truth, though. In the muscles, there are neuromiscular adaptations, more vascularisation, more mitochondria, and probably Type II muscle type conversions that make it so that the system does not need as much oxygen for the same task anymore - or rather is much more efficient in allocating the resources so that the systemic burden is lower. Commented Sep 16, 2023 at 21:10

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