ELI5: When knocked unconscious, what bodily function wakes a person back up? What determines when and how quickly it happens?

Definitely depends on what part of your brain needs to recover. I worked in an ER and our “go to move” was to take our knuckles and rub them vigorously across the sternum of a patients chest. (The bone between your breast) the pain wakes you REAL fast.

Comes in handy for less serious events like your buddy is black out drunk or gets knocked out at a bar.

Explain Like I`m Five: good questions, best answers.