Ever feel like you are drifting off to sleep, then suddenly jerk awake? That quick kick, twitch, or falling sensation may be a hypnic jerk, sometimes called a “sleep start.”
Hypnic jerks are sudden, involuntary muscle movements that happen as the body transitions from wakefulness to sleep.
SleepFoundation.org notes that they are common and generally harmless, though they may be more likely to occur when someone is stressed, sleep deprived, or using stimulants such as caffeine or nicotine.
Mayo Clinic describes these quick, involuntary movements as a form of myoclonus, the broader term for sudden muscle jerks. Hiccups are another familiar example.
That does not mean every nighttime twitch should be dismissed. Medical News Today notes that persistent twitching can sometimes point to an underlying health issue, and people may want to contact a doctor if episodes are frequent, disruptive, or affecting their ability to fall or stay asleep.
For most people, though, an occasional bedtime jolt is less mystery than misfire: a brief, startling reminder that falling asleep is an active transition for the body and brain.
Sources: Sleep Foundation; Mayo Clinic; Medical News Today.
