Drained and exhausted, you are finally in bed sinking into what will be a deep sleep, when your body starts ‘falling’ and it suddenly jerks to stop that ‘fall.’ You will, of course, wake up immediately and wonder where it came from.
And no matter how many times it happens, you never get used to it, it never feels less abrupt, and it never gets any better. The falling sensation can even be terrifying, ending with an involuntary, sudden, and shocking jump.
If this has happened to you at least once, you are not alone. In fact, up to 70% of people experience this phenomenon, also known as hypnic jerks (or sleep starts). Nobody really knows for sure what causes these sudden jerks.
The Science Behind Hypnic Jerks
Although a solid explanation for how and why hypnic jerks happen hasn’t been offered, there are two theories that suggest some reasons for this. One states that the hypnic jerks happen as a result of the natural downshifting of the nervous system as you’re falling asleep.
This theory explains that these twitches come as a response to the shifts of muscle tone, which occur as your breathing and heart rate slow down, and your body temperature naturally drops. In this transition, the twitches come as a response to this downshifting.
The other theory suggests that it happens because of the rapid relaxation of your muscles, which your brain interprets as if you are actually falling. In response, it signals the muscles to tense up, so that you could protect yourself.
Whatever the case, researchers think that this response of the body comes under the influence of external factors, such as caffeine, tobacco, sleep deprivation. It’s even associated with the intake of medications like Adderall and Ritalin, which can have similar effects.
Is It Normal to Have Hypnic Jerks Every Night?
These jerks are sudden and involuntary, which means you have no control over them. Some people may feel startled and some may feel like they are falling. But whatever the case, it is considered to be absolutely normal to experience hypnic jerks during sleep.
