Tired out, you finally hit the bed and are about to fall into a deep sleep. Then your body starts to “fall” and suddenly jerks to stop that feeling. Of course, you wake up right away and wonder what’s going on.
No matter how often it occurs, you never get used to it. It always feels just as sudden and never gets any less startling. The falling feeling can even be scary, ending with an involuntary, quick, and shocking jump.
If this has happened to you even once, you’re not alone. Actually, up to 70% of people go through this, called hypnic jerks (or sleep starts). Nobody really knows for sure what causes these sudden jerks.
Though there’s no definite explanation for how and why hypnic jerks occur, two theories suggest some possible reasons. One theory says hypnic jerks happen because of the natural slowdown of the nervous system as you’re falling asleep.