Book 2, Question 16
Why Do We Jerk Awake When We Fall Asleep?
Have you ever been drifting off, and then your whole body suddenly jumped? That is a sleep switch glitch. Scientists call it a hypnic jerk.
From the book
Page from A Million Whys Book 2
More fun facts
- A hypnic jerk is also called a sleep start.
- Your brain makes your muscles tense, as if to catch yourself from falling, and that makes your body jerk.
- Hypnic jerks are most likely just as you start to fall asleep.
- Some people feel like they are falling or floating when it happens.
- Hypnic jerks happen to people who are perfectly healthy.
- They are a kind of myoclonus, which means a quick, sudden muscle twitch.
- Lots of people fall right back asleep after one.
Sources: KidsHealth (Nemours), Cleveland Clinic, Cleveland Clinic
Questions kids ask
Should I worry about jerking awake?
No. Sleep starts are nothing to worry about, and most people fall right back asleep.