December 20, 2023

Why Do We Jerk or Twitch When Falling Asleep?

man wearing green printed crew neck shirt while sleeping

Have you ever been almost asleep and suddenly felt a twitch or jerk? This unexpected muscle movement is called a hypnic jerk. It happens to many people as they are about to fall asleep. But what exactly causes these sudden movements? Let’s dive into understanding why these twitches happen as we drift off to sleep.

What’s a Hypnic Jerk?

A hypnic jerk is an involuntary muscle spasm that occurs just as you’re starting to fall asleep. It can involve a small part of your body, like an arm or a leg, or it might be a jerk of your whole body. People often describe it as feeling like they are falling or experiencing a quick shock. Sometimes, they even have a dream-like vision or feel like they’re hallucinating.

Sleep Stages and Hypnic Jerks

To get why hypnic jerks happen, we should first look at how we sleep. Our sleep is split into different stages. It starts with light sleep (Non-REM stage 1), moves into deeper sleep (Non-REM stage 3), and finally reaches REM (Rapid Eye Movement) sleep. Hypnic jerks usually happen during the transition from being awake to entering the first stage of light sleep.

The Science Behind Hypnic Jerks

Scientists have a few ideas about why hypnic jerks happen:

The Evolution Theory: Some scientists think hypnic jerks are an old reflex. They believe when our ancestors slept in trees, the brain made these jerks happen to wake them up so they wouldn’t fall.

The Brain Activity Theory: As we fall asleep, our brain slows down in different areas at different times. A hypnic jerk might happen if nerves in the brain get mixed up during this slowdown.

The Body Signals Theory: Another idea is that as our muscles relax, the brain gets confused and thinks we are falling. The jerk is the body’s way of waking us up to stop the fall.

Who Experiences Hypnic Jerks?

Hypnic jerks are common and can happen to anyone, no matter their age or gender. But how often they happen and how strong they are can be different for each person. Some people might feel them more, especially when they are stressed or not getting enough sleep.

Things That Make Hypnic Jerks More Likely

Certain things in our daily life can increase the chances of hypnic jerks:

  • Stress and Worry: Being very stressed or worried can lead to more hypnic jerks.
  • Caffeine and Other Energy Boosters: Drinking things like coffee or energy drinks before bed can make these twitches more likely.
  • Intense Exercise in the Evening: Doing hard workouts at night can make your nervous system more active, leading to sleep twitches.
  • Not Enough Sleep: Not sleeping enough or having a messed-up sleep schedule can also be a reason.

Are Hypnic Jerks a Problem?

For most people, hypnic jerks are just a surprising part of falling asleep and aren’t harmful. They only become a problem if they make it hard for you to fall asleep or if you start worrying a lot about them.

How Can We Reduce Hypnic Jerks?

If you’re bothered by hypnic jerks, here are some tips:

  • Create a Calming Bedtime Routine: Relaxing things like reading or taking a warm bath can make it easier to fall asleep.
  • Avoid Caffeine and Energy Boosters: Try not to have caffeine or similar things later in the day.
  • Exercise Regularly, But Not Too Late: Regular exercise is good for sleep, but avoid hard workouts right before bedtime.
  • Make Your Sleep Space Comfortable: A quiet, dark room with a comfy temperature helps with better sleep.
  • Keep a Consistent Sleep Schedule: Going to bed and waking up at the same time every day can help regulate your sleep.

When to Get Help

Usually, hypnic jerks are nothing to worry about. But if they make you very anxious or you have other symptoms like loud snoring or stopping breathing (which might be sleep apnea), it’s a good idea to talk to a doctor.

Interesting Facts About Hypnic Jerks

Did you know that not everyone experiences hypnic jerks in the same way? Some people might have them often, while others rarely feel them. And for some, hypnic jerks can be strong enough to wake them up, while for others, they are just a mild twitch.

The Link Between Dreams and Hypnic Jerks

Sometimes, hypnic jerks can be tied to what you’re dreaming about. For example, you might dream about tripping or falling, and the hypnic jerk happens as a response to that dream. It’s like your body reacts to what’s happening in your dream world.

Children and Hypnic Jerks

Children can experience hypnic jerks, too. Parents sometimes notice these jerks in their sleeping babies or young children. Like in adults, these twitches in children are usually normal and not a cause for concern.

Hypnic Jerks and Overall Health

While hypnic jerks themselves are not harmful, they can be more frequent if you’re not taking good care of your health. This includes being stressed, not getting enough exercise, or having poor sleep habits. Taking care of your overall health can help reduce the frequency of hypnic jerks.

Myths About Hypnic Jerks

There are some myths about hypnic jerks. For example, some people think they happen because of bad dreams or nightmares, but that’s not always true. Hypnic jerks can happen without any dreams at all. They are a natural part of the body’s transition into sleep.


In conclusion, hypnic jerks are a normal, usually harmless part of going to sleep. They show how interesting and complex our sleep process is. Knowing what they are and why they happen can help you sleep more peacefully and not worry about them. Remember, if they start to bother you a lot, it’s always a good idea to ask a sleep expert or doctor for advice.

Ready to Transform Your Sleep?

If you’re seeking a deeper understanding of your sleep patterns or looking for personalized strategies to improve your sleep quality, we’re here to help.

We provide support and treatment for chronic sleep difficulties through assessment and sleep therapy (Cognitive Behavioral Therapy for Insomnia) for people in British Columbia, Ontario, and consultation and sleep health education globally.


American Academy of Sleep Medicine: Sleep Starts

NHS: Hypnic Jerks

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