Why does the human body jerk/shock itself awake sometimes while trying to sleep?

Question

Why does the human body jerk/shock itself awake sometimes while trying to sleep?

In: 2959

Answer 1

It’s a reflex where the body thinks it is potentially about to fall, so jolts you awake. It’s probably most commonly experienced if you are asleep sitting up and your head starts to fall, but can happen somewhat randomly. It’s from our evolutionary history where sleeping somewhere you could fall from actually was a thing.