eli5 why is exercise supposed to make you tired if atp is not stored?

Question

I read that atp is produced constantly as needed and that you can only store about a minutes worth, so how is exercise supposed to make you tired and sleepy if you’re not using up your energy?

In: 19

Answer 1

Glycogen in muscles is depleted, metabolic byproducts build up and need to be cleared, muscles form micro tears along with other connective tissues, and all of that needs to be resolved.