But what exactly happens to your body when you're in a coma? First we have to be clear that comas are very different from sleep. Despite the fact that the origin of the word comes from the Greek for Koma, or deep sleep, comas are not sleep however and are instead various forms of unconsciousness that render a person unable to respond to any external stimuli. You can play the loudest, heaviest death metal in the world right next to someone who's comatose, and you won't succeed in doing anything except really annoying the neighbors. Likewise you can even physically hurt people in a coma and they will remain completely oblivious and unresponsive. In times not too distant past this was sometimes used as treating, with doctors trying to shock their victims back into consciousness. Everything was tried from exposing parts of the body to open flames to severely dropping the body's temperature with ice, to even bloodletting from the head directly. One treatment even included wholly emptying the stomach, we guess because the doctors thought that if a patient got hungry enough, the body would force them to wake up. Or maybe they really were just throwing everything including the kitchen sink at the problem, which we're sure was also tried. Comas can occur as a result of serious trauma or as a deliberate medical treatment by doctors. They are typically brought on by traumatic head injury.