It turns out our muscles don’t run out of energy when we get tired. It’s not that we physically cannot continue to work out even when we think we can’t. It’s our brain’s preemptive shut down mechanism that allows body to conserve energy for what’s after the workout (brain doesn’t particularly care) and make us stop exercisin before we can hurt ourselves according to Fitness Magazine.
Tim Noakes, a sports physiologist at the University of Cape Town, has measured cyclists’ muscle use and found that when they got exhausted they still had 50% percent of their muscle fibers ready to work.
The scentists propose that our brains work well in advance of any possible damage to allow us to have enough energy and healthy limbs in case we have to sprint to run away from predators or bring food home from hunting.
They note that there are obvisouly physical limits for the human body, but we start feeling tired well in advance of any damage or even muscle fatigue.