You’re peacefully falling asleep when suddenly, you jolt awake as if falling into an abyss. It’s a common yet unsettling phenomenon, but usually harmless. Let’s explore the science behind these sleep disturbances.
What Are Hypnic Jerks?
The feeling of falling during sleep often comes with a sudden body jerk or twitch, called a hypnic jerk or sleep start. It happens when transitioning from wakefulness to sleep and can be accompanied by:
- A sudden muscle spasm that wakes you up.
- The sensation of falling from a cliff, stairs, or bed.
- A quick dream or hallucination before waking.
- A mild shock or twitch in your arms, legs, or whole body.
Hiccups are also myoclonic jerks, sharing a similar neurological cause with hypnic jerks.
Causes of Hypnic Jerks
Scientists haven’t found the exact cause, but there are two main theories:
- Brain’s Misinterpretation: As you start to sleep, your body relaxes. Sometimes, your brain mistakes this relaxation for danger, like falling from a height, and sends a signal to your muscles to contract.
- Survival Mechanism: Our ancestors slept in trees. A hypnic jerk might have been the brain’s way to prevent them from falling out. Although we don’t sleep in trees anymore, this reflex may still be in our nervous system.
Factors Increasing Hypnic Jerks
- Stress and Anxiety: High stress levels make it hard for your body to relax, increasing the chance of hypnic jerks.
- Caffeine and Stimulants: Drinking coffee, tea, or energy drinks before bed over – stimulates the nervous system, making muscles twitch more.
- Late – Night Exercise: Intense physical activity in the evening keeps muscles alert, making it difficult for them to relax.
- Poor Sleep Habits: Lack of sleep or an inconsistent bedtime can lead to a more abrupt sleep transition, raising the likelihood of hypnic jerks.
