Home » Sleep Disorders » Sleep Starts
January 2021 |  Reviewed by:  Shelley Hershner, MD and Reeba Mathew, MD

What are sleep starts?

Do you have sudden, brief jerks of your body as you fall asleep? Do these jerks mainly affect your arms and legs? Do they occur along with one or more of the following sensations?

  • A feeling that you are falling
  • A sensory flash
  • A visual dream or hallucination

If you answered yes to these questions, then you may have sleep starts.

Sleep starts are also known as hypnic or hypnagogic jerks. They are sudden, brief, and strong contractions of the body or one or more body segments. They occur as you are falling asleep. Some people also have a sensation of falling.

Sleep starts usually consist of one strong jerk that affects much of the body. The arms and legs are most likely to be affected. A sharp cry may also occur. A sleep start does not always wake you up. This means that you may not recall a jerk that was noted by a bed partner.

At times, many jerks may occur one after another. They can be frequent, intense, and repetitive. Intense or frequent sleep starts may lead to a fear of falling asleep. This can also lead to anxiety and worry. Sleep loss may result if repeated jerks keep you awake. Anxiety caused by sleep starts can also make it hard to fall asleep. Insomnia can result if this problem continues over time.

It is possible to be injured by a sleep start. The jerk may cause you to bruise a foot against the bed or kick a bed partner.

What are risk factors of sleep starts?

Sleep starts are very common. They are a fairly universal part of the process of falling asleep. They may not seem so common because they often are not recalled.

They have been reported to occur in 60% to 70% of people. In most people, they only occur from time to time. Sleep starts affect all ages and both men and women. Adults are more likely to complain about frequent or intense jerks.

The frequency and intensity of sleep starts can be increased by the following:

  • A high intake of caffeine or other stimulants
  • Prior intense physical work or exercise
  • Sleep deprivation
  • Emotional stress

It is also important to know if there is something else that is causing your sleep problems. Instead of being sleep starts, your problems might result from the following:

  • Another sleep disorder
  • A medical condition
  • Medication use
  • A mental health disorder
  • Substance abuse

How to diagnose sleep starts?

Sleep starts are very common and do not require treatment in most people. You should see a sleep doctor if the jerks, or your fear of them, are keeping you from getting enough sleep.

The doctor will need to know when the sleep starts began. The sleep doctor will also want to know what else has been going on in your life. You should complete a sleep diary for two weeks. The sleep diary will help the doctor see your sleeping patterns. This data gives the doctor clues about what is causing your problem and how to correct it.

The doctor will need to know your complete medical history. Be sure to inform her of any past or present drug and medication use. Also, tell your doctor if you have ever had any other sleep disorder.

No tests are needed to detect sleep starts in most people. Your doctor may have you do a sleep study if your jerks are severe. This study is called polysomnography. It charts your brain waves, heart rate, and breathing as you sleep. It also records how your arms and legs move. This study will help reveal if the sleep starts are related to any other sleep disorder, such as sleep apnea.

How to treat sleep starts?

Sleep starts may not need treatment. They may also decrease as you do the following:

  • Get enough sleep
  • Avoid caffeine and other stimulants
  • Reduce stress

If they are causing sleep disruption or anxiety, the doctor may prescribe medications to help you.