Hypnogogic jerks are also known as sleep starts or hypnic jerks. They’re strong, sudden, and brief contractions of the body that occur just as you’re falling asleep.

If you’ve ever been drifting off to sleep but suddenly wake with a jolt and a jerk of the body, you’ve experienced a hypnogogic jerk.

Named for the transitional period between wakefulness and sleep, these involuntary twitches resemble the “jump” you may experience when you’re startled or scared.

Hypnogogic jerks are common. Research suggests up to 70 percent of individuals experience these contractions. However, not every one of these moments will force you awake. You may sleep through many of them.

Hypnogogic jerks are also sometimes called sleep twitches, night starts, or myoclonic jerks. A myoclonus is an involuntary muscle twitch; hiccups are another form of myoclonus.

No matter what it’s called, this condition isn’t a serious disorder. It’s unlikely to cause any complications or side effects. However, you can take steps to prevent involuntary jerks from happening. Read on to learn more.

It’s important to understand that hypnagogic jerks aren’t a disorder. They’re a natural phenomenon and very common.

For that reason, symptoms of this condition aren’t signs of a problem. They’re simply things you may experience.

Symptoms of a hypnagogic jerk include:

  • jerk or jolt of a muscle or body part
  • falling sensation
  • sensory flash
  • dream or hallucination that leads to a startle, jump, or fall
  • quickened breathing
  • rapid heartbeat
  • sweating

It’s not clear why hypnagogic jerks occur. Healthy individuals may experience this phenomenon without a known cause.

Research into this sleep phenomenon is limited, but some theories exist. These possible causes of hypnagogic jerk include:

  • Anxiety and stress. Anxious thoughts or stress and worry may keep your brain active, even as your muscles try to relax as you drift off to sleep. This may cause your brain to send out “alert” signals as you’re dozing or even while you’re asleep. Likewise, if you start to experience more jerks or twitches, you may develop anxiety about sleeping because you begin to worry about these sleep starts.
  • Stimulants. Caffeine, nicotine, and alcohol can all impact your body’s ability to fall asleep naturally and stay asleep. Chemicals in these products may prevent your brain from reaching deep sleep and instead startle your brain from time to time.
  • Exercise. Daily physical activity can help you get better shut-eye, but exercise that’s too close to bedtime may make you more likely to experience sleep starts. Your brain and muscles may not be able to slow down for sleep quickly enough.
  • Sleep deprivation. Sleep disturbances and poor sleep habits may be linked to hypnagogic jerks.
  • Evolutionary hypothesis. Research from the University of Colorado suggests the origins for this sleep phenomenon go back further, to our evolutionary ancestors. They propose the hypnagogic jerk was a way of helping primates readjust their sleeping positions before dozing off so they didn’t fall out of a tree or get hurt during their slumber.

Hypnagogic jerks don’t require treatment. They’re not a serious condition, and they won’t cause complications.

Instead, treatment for hypnagogic jerks focuses on preventing them from happening. These steps may help you fall asleep and stay asleep without the interruption from sleep starts:

  • Avoid caffeine. A morning cup of joe is OK, but anything after midday may set you up for sleep disturbances. Try to reduce your overall caffeine consumption level, especially in the afternoon and evening.
  • Avoid stimulants. In addition to caffeine, you should limit the amount of nicotine and alcohol you use in a day, especially after midday. A glass of wine before bed may help you doze off, but you’ll be more likely to have restless sleep and to wake up.
  • Exercise earlier. Get your daily sweat session in before noon. If you can’t swing that, try to do only low-intensity forms of exercise in the evening, such as Pilates or yoga.
  • Adopt a pre-sleep routine. For 30 minutes before bedtime, disconnect from technology, turn down the lights, and slow down. Help your brain prepare for sleep by cranking down your energy use and relaxing before you try to get shut eye. Try these 10 natural ways to sleep better.
  • Breathing exercises. When you’re in bed, inhale for 10 counts, hold for 5 counts, and exhale slowly for 10 counts. Do this exercise several times to help slow your heart rate, brain, and breathing.

If you develop anxiety about falling asleep and experiencing hypnagogic jerks, you may want to talk with a doctor about your concerns and experiences.

Likewise, if this sleep disturbance is preventing you from getting sleep and being well-rested, make an appointment with your doctor. They may prescribe sleep medications or muscle-relaxing drugs to help you ease into sleep.

It’s important to remember, however, that hypnagogic jerks are not a disorder. They’re not a serious condition. They’re not even uncommon. Many people experience these starts in their sleep.

Taking time to relax before bed may help reduce how often you experience them. Likewise, a few changes to your daily routine may set you up for better sleep at night.