How does the body suddenly regain energy after staying up long enough?

Question

When pulling an allnighter at some point all tiredness just vanishes and there is a burst of energy. How does the body decide when to do that and why?

In: Biology

Answer 1

I think the hormones that make you sleepy simply run out when you push through your tiredness, and the body needs time to build up a new reservoir. That’s what it feels like at least.

Answer 2

Maybe body got tired of feeling tired and had to take a rest?