2. A survival reaction inherited from our ancestors?

Some researchers believe it’s an evolutionary glitch—a remnant from the days when our ancestors slept in trees. A little brain check to make sure we weren’t about to fall from a branch while dozing off.

3. Factors that accentuate these spasms

Certain things can make these jolts more frequent or intense:

• Stress or anxiety: An overactive mind keeps sending signals to your body, even during rest
• Caffeine or stimulants: These delay sleep and ramp up muscle activity
• Exercising too late: It keeps your body in “go mode,” making it harder to fully relax
• Sleep deprivation: The more exhausted you are, the more abrupt the switch from wakefulness to sleep becomes

Should you be concerned?

Here’s the good news: hypnic jerks are completely harmless for most people. They happen to about 60–70% of us—regardless of age or gender—and aren’t considered a sign of a sleep disorder.

When should you talk to a doctor?

• If the jerks happen frequently and seriously disrupt your sleep
• If you also experience cramps, ongoing fatigue, or pain
• If they come with sleep paralysis or regular hallucinations

How to calm things down at bedtime:

• Wind down with a relaxing routine—think meditation, light reading, or calm music
• Cut back on caffeine and limit screen time before bed
• Try to go to bed and wake up at the same time each day
• Stay active during the day, but avoid intense workouts in the evening