Eli5: Why do we need to sleep so much, what happens in the body when asleep that cannot happen while normal resting or relaxing? Or is it just for the brain?

Question

Eli5: Why do we need to sleep so much, what happens in the body when asleep that cannot happen while normal resting or relaxing? Or is it just for the brain?

In: Biology

Answer 1

Not an expert, but here are some things I haven’t seen mentioned:

a) our brains are big, relative to our body, more than most mammals.

b) we have evolved to not need shorter sleep. Most animals are light sleepers because of their environment. Most commonly, most wild animals are light sleepers and sleep in smaller intervals because they remain alert for predators. There are less common sleep patterns like dolphins, who need to stay awake to go up for air so they sleep one half of their brain at a time.

c) ultimately, we don’t know and the field of sleep is still a huge mystery.