If your body suddenly jerks while you’re falling asleep, here’s what it means

The Science Behind Hypnic Jerkys

Although there’s no complete explanation for how and why hypnic jerks occur, two theories suggest some causes. One holds that hypnic jerks are the result of the nervous system’s natural slowing down during sleep.

The explanation lies in the changes in muscle tone that occur as a result of slowing breathing and heart rate, and the natural drop in body temperature. In this transition, theory suggests that contractions are a response to this drop.

The other theory suggests that this happens because of the rapid relaxation of the muscles, which the brain interprets as if you were actually falling. In response, it signals the muscles to contract, so you can protect yourself.

However, researchers believe that this body response is influenced by external factors, such as caffeine, tobacco, sleep deprivation, and is even associated with the use of drugs like Adderall and Ritalin, which can have similar effects.