Do you ever wake from sleep and realize you can’t move your arms or legs, lift your head, or wiggle your fingers or toes? You’re aware of your surroundings, but you can’t move or speak. You might even see weird visions or hear strange sounds.
This is called sleep paralysis, and it occurs when part of the brain is awake, but the parts controlling your body are still asleep—so when you try to move, you’re unable to for several seconds or even a few minutes. Episodes can be broken by either waking up fully or falling back to sleep. Either way, it can be extremely frightening.