system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 - How does the body regain conciousness after being unconcious? What triggers us to wake up?
gpt
It's not just one thing, or patients wouldn't be stuck in comas.

In order to be conscious a lot of things need to be working properly.  The brian needs to be undamaged, at normal pressure, and the blood needs to be at the right chemical balance with oxygen and sugar to power the brain.