Do you really know? Why do we startle when we fall asleep?
Jun 21, 2025
Ever felt like you're falling just as you drift off to sleep? That jolt is known as a hypnic jerk, a surprising muscle spasm that wakes you up! It's your brain's way of checking in while your body relaxes. These involuntary twitches can feel annoying but are quite common. Curious about what causes them? The discussion covers the science behind this baffling bedtime quirk and offers tips to reduce their frequency for a more restful night's sleep.
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What Are Hypnic Jerks?
- Hypnic jerks are involuntary muscle spasms occurring as you fall asleep, also called myoclonus.
- They often feel like falling and serve as a quick brain systems check between wakefulness and sleep.
Factors Amplifying Hypnic Jerks
- Stress, exercise buzz, some medications, tiredness, lack of sleep, and caffeine can amplify hypnic jerks.
- These factors increase the likelihood and intensity of the startling muscle spasms before sleep.
Sleep Apnea's Connection to Jerks
- Conditions like sleep apnea can cause muscle contractions due to oxygen drops that awake the brain.
- These jerks in sleep apnea are part of an alert system to restore normal breathing.