Overall, there’s still a lot scientists don’t know about sleep paralysis and why some people are more prone to it than others, reports The Conversation.
Falling asleep is a bit like flicking off a light switch. One moment we are awake, but then the switch is flicked and we fall asleep. That’s how it’s supposed to work, anyway. But sometimes, the switch gets a bit “sticky” and the light flickers between being awake and asleep. This is what happens with sleep paralysis – when you wake up but feel like you can’t move.
In the olden days, some people called sleep paralysis the “Night Hag” and said it felt like a spooky witch or demon was sitting on your chest. Now we know it is quite a common sleep problem or what doctors call a parasomnia, caused by a little brain hiccup. And thankfully, it usually doesn’t last very long.
With sleep paralysis, some parts of your brain are awake and still active but other parts are fast asleep.
The sleeping part is the section of the brain that tells the muscles to relax while we sleep so we don’t act out our dreams. Evolution probably gave us that trick because acting out dreams can be harmful to yourself or others (although this trick doesn’t always work and some people do act out their dreams).