Hypnic Jerk: Why Do I Twitch Before Falling Asleep?

April 2, 2024 | Casper Editorial Team

Fact checked by Jonathan Eilenberg, CPE

Hypnic jerks, also known as sleep starts, are sudden, involuntary muscle contractions that some people experience as they are falling asleep. The exact cause of these twitches is not fully understood, but there are several theories.

You’re lying in bed after a long day, slowly drifting off into a deep, peaceful sleep, when suddenly, you feel as though you’re falling from a great height, and you snap awake. Your limbs might jolt violently without your control, and you might even hear sounds (or make some of your own). 

Now you have to start the process of falling asleep all over again. 

This is what’s known as a hypnic jerk, also called a hypnagogic jerk, or a sleep start.1 While the occasional hypnic jerk isn’t dangerous, frequent hypnic jerks can become sleep disruptions and create personal anxieties surrounding falling asleep.1

So, you’re asking, “why do I twitch before falling asleep?” 

While the reason for hypnic jerks isn’t fully understood, there are several factors that may increase them, from excessive caffeine intake, to heightened stress and anxiety. Learn more about these pesky sleep disturbances and what you can do to stop them with this insightful sleep guide. 

What is a Hypnic Jerk?

Hypnic jerks are a strange sensation if you’ve never experienced one before. 

Some people describe it as a sudden and vivid falling sensation or hallucination, while others say it’s more like a sudden shock or slap that immediately wakes them up.2 Despite these differences, all hypnic jerks1:

  • Are sudden and brief
  • Affect most or all of the body
  • Are involuntary movements

Hypnic jerks fall under the wider umbrella of myoclonus, a set of conditions characterized by uncontrollable jerking or twitching.3 In addition to sleep starts, it includes everything from hiccups to exercise-induced muscle spasms.3 

You may have experienced a hypnic jerk without realizing it. Many people twitch without waking up, and only learn what happened from a partner who witnessed it.1 For others, hypnic jerks force them wide awake and make it difficult for them to figure out how to fall back asleep

Hypnic jerks are incredibly common: between 60% to 70% of people have experienced them before.1 For some people, this is only an occasional occurrence, and doesn’t require any type of treatment. But for others, it’s an expected—and dreaded—part of their night or even when they’re just trying to take a power nap

The intensity and frequency of hypnic jerks can make falling asleep not only difficult, but worrisome. Some people say they experience it at the same time every night, like clockwork.2 So why does this happen?

Hypnic Jerks: Potential Causes

Unfortunately, not much is known about why hypnic jerks occur. It’s often explained as a disconnect between the different parts of your brain—an improper shutdown. One part begins to fall asleep faster than another, causing confusion and that strange falling sensation.2

Sleep deprivation is one of the main causes of this disconnect in the brain2: less sleep leads to poorer sleep.  

Hypnic jerks might also be tied to your circadian rhythm. Your circadian rhythm, also known as your internal or biological clock, is in charge of many different regulatory systems in the body—most importantly, your sleep cycle.4

Falling asleep is actually a lengthy process. You begin in stage 1, which is a light sleep you can be easily woken up from. After about 90 to 110 minutes, you move into stage 2 sleep, which involves decreased movement and lower brain activity.5

It’s during the transition from the first stage of light sleep, to the second, deeper stage of sleep that hypnic jerks most typically occur. This may be why many people experience hypnic jerks around the same time each night.2

Factors that Increase the Frequency of Hypnic Jerks

Most people experience hypnic jerks at some point in their lives—it’s almost universal. But there are some unhealthy habits and other factors that can cause you to experience them at higher rates. For example1:

  • Excessive caffeine intake, especially in the few hours before bed
  • Strenuous work or exercise before bed
  • High levels of stress

All of these factors are known to contribute to poor sleep hygiene, which is why underlying sleep disorders or other health issues may be at fault for frequent and intense hypnic jerks.1

How Hypnic Jerks Affect Our Sleep Quality

Hypnic jerks themselves are not harmful to the body. Yes, they cause you to jolt or twitch involuntarily, but they are very common and very brief. The most that may happen is that you bruise a foot or hand from lashing out in bed.1 

What’s more concerning is the psychological response to frequent and particularly intense hypnic jerks. The feeling of falling, or being shocked, is unpleasant, and often downright scary, especially when you’re trying to fall asleep. The only thing worse than the feeling itself is the anticipation of it. 

In rare cases, this causes some people who regularly experience hypnic jerks to develop a fear of falling asleep.1 This fear can cause feelings of anxiety before bed, which in turn, increases the likelihood of hypnic jerks occurring.

If hypnic jerks and sleep anxiety continue, they can lead to more serious sleep conditions and disorders, such as sleep deprivation and insomnia.1

So, left unchecked, frequent and intense hypnic jerks can seriously affect your daily life and overall well-being. 

But what can you do when you can’t stop twitching?  

When to Seek Help for Hypnic Jerks

If you are losing sleep due to hypnic jerks, or are afraid of going to sleep each night, it may be time to see a medical professional for help. 

A sleep doctor can help you find the root cause of your hypnic jerks through self-reporting tools like sleep diaries, or by conducting a sleep study that records your important vital signs, such as brain waves and breathing patterns, as you sleep.1 They will also look at your medical history for any other instances of sleep disorders.

By prescribing mental health therapy, and potentially medication, your doctor can help you find more peace at night. 

Tips for Reducing Hypnic Jerks

The good news is that, since hypnic jerks are so closely related to other sleep disorders, there are many tried-and-true ways you can alleviate them, and from the comfort of your own home. 

Improving your poor sleep quality begins with practicing good sleep hygiene. Sleep hygiene encompasses all the healthy habits and positive external factors that promote better sleep.6 

Here are just some of the ways you can practice good sleep hygiene for less hypnic jerk-related sleep disruptions.

Create a Positive Sleep Environment

Your bedroom environment is essential to getting good sleep. To keep your bedroom sleep-friendly, follow these tips6:

  • Make your room as dark and quiet as possible, using curtains, eye masks, and earplugs if necessary.
  • Keep yourself cool by controlling the room temperature, or sleeping on a mattress with cooling technology.

Remember that your bedroom should only be used for sleeping. Doing work or any leisurely activities will lead you to associate your bedroom with wakefulness, not sleep.6 

Be Consistent

Sleep problems often arise due to inconsistent sleep schedules that disrupt your internal clock, or your circadian rhythm. These inconsistencies lead to sleep deprivation, which can contribute to hypnic jerks.2 

Try to go to bed and wake up at the same time each day, even on the weekends. You can promote a consistent sleep schedule by following a bedtime routine. It can be as simple or as detailed as you’d like—just make it feasible for you. Learn more about how to fix your sleep schedule in our blog.

Avoid Stimulants

Stimulants are one of the main causes of frequent hypnic jerks.1 

The most common stimulants that disrupt your sleep are caffeine and nicotine. As their name suggests, stimulants stimulate your body by increasing your heart rate and blood pressure, which can make it difficult to fall asleep properly.6 

Reduce Stress

After you’ve taken care of all the external factors affecting your sleep, like excess light and noise, it’s time to turn inward and address your emotional stress levels. 

There are several effective strategies for reducing stress before bed, including6:

  • Limiting electronic device use a few hours before bed
  • Having a consistent, calming bedtime routine, like reading a book or taking a warm bath
  • Practicing mindful meditation or deep breathing exercises

You can also try to reduce stress during the day through regular exercise and mindfulness. 

If you still struggle to relieve your sleep-related stress due to your fear of hypnic jerks, it may be helpful to seek help from a sleep doctor or mental health professional who can guide you through your worries and suggest other strategies for combating them. 

Feel More Grounded in Bed on a Casper Mattress

When you get into bed, you want to feel like you’re lying on a soft cloud—not like you’re falling through one. A comfortable and supportive mattress may be the key to avoiding those distressing hypnic jerks that make falling back to sleep so difficult. 

Whether your hypnic jerks are an isolated occurrence, or tied to a more serious sleep disorder, practicing good sleep hygiene will help you sleep more soundly, with fewer disruptions. 

That all starts with finding a quality mattress you can trust. 

Casper mattresses are rigorously tested by sleep engineers in our Casper Labs so you can achieve your best night’s sleep. With multiple zones of support and cooling Snow Technology, we help you fall asleep—and stay asleep.  


  1. American Academy of Sleep Medicine. Sleep Starts. https://sleepeducation.org/sleep-disorders/sleep-starts/ 
  2. Time. Why Does Your Body Twitch As You’re Falling Asleep? https://time.com/5008693/sleep-start-hypnic-jerk/ 
  3. Mayo Clinic. Myoclonus. https://www.mayoclinic.org/diseases-conditions/myoclonus/symptoms-causes/syc-20350459 
  4. National Sleep Foundation. Understanding Circadian Rhythms. https://www.thensf.org/what-is-a-circadian-rhythm/ 
  5. Verywell Health. The Stages of Sleep. https://www.verywellhealth.com/the-stages-of-sleep-2224272 
  6. Better Health Channel. Sleep hygiene. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/sleep-hygiene