You are all settled in for the night, cozy and warm in your bed. You start to drift off to dreamland, and all of a sudden you are falling or something hits you in the face. Whatever it is, you are suddenly startled awake with a jolt.
This strange sensation actually occurs on a regular basis to many people, and scientists have finally figured out what it means.
This process of being startled awake is referred to as the “hypnic jerk.” Although everyone has their own unique experiences with the hypnic jerk and describe the feeling a little differently, it is often explained as the feeling of falling.
The hypnic jerk is most often seen when a person falls asleep rapidly during or after an exhaustive state. When the body is exhausted, the brain can process the stages of sleep too quickly. This confuses the brain into thinking that the body and its major systems are failing. The brain then responds by jolting you awake with a burst of chemicals and then builds a dream designed to wake you up.
Check out this video from Discovery News to better understand the hypnic jerk and why we twitch.