Sleep paralysis: what is it, causes, symptoms, how to stop

If you’ve ever had a nightmare where you couldn’t move your body, you may have had an episode of sleep paralysis. While it may sound scary, sleep paralysis is more common than you might think, and it’s not at all dangerous. 

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Sleep paralysis is when you regain awareness during a sleep cycle, but your muscles are still relaxed to the point that you cannot move. It’s easy to feel distressed in this situation. Some people may even feel like they’re being suffocated and have frightening hallucinations (Farooq, 2020).

There’s a lot we don’t know yet about sleep paralysis, and research is ongoing. If you have this condition or are worried you might have it, keep reading to learn about who gets sleep paralysis, the causes, symptoms, prevention, and treatments.

Who gets sleep paralysis?

Sleep paralysis can happen to anyone at any age. Typically, symptoms first start in childhood or adolescence. Most people continue having symptoms in their 20s and 30s. Sleep paralysis is divided equally between genders (Farooq, 2018).

Though it is difficult to determine the exact number of people who experience sleep paralysis, it’s estimated that about 8% of all people have an episode of sleep paralysis in their lifetimes. Sleep paralysis can happen to completely healthy people with no underlying health conditions or people diagnosed with narcolepsy. Sometimes sleep paralysis episodes happen to people with severe psychological stress, sleep deprivation or lack of sleep, or a disordered sleep cycle (Farooq, 2018). 

The American Academy of Sleep Medicine recommends that adults get at least seven hours of sleep at night.

Sleep is divided into sleep cycles. There are four primary stages of sleep in each cycle (some divide the cycles into five stages to include the time right before your eyes close). Each complete cycle lasts about 90 minutes to two hours long, so a person with good sleep habits has at least 3–4 sleep cycles per night (Watson, 2015). 

The stages of sleep in a sleep cycle are grouped into rapid eye movement (REM) and no rapid eye movement (NREM) sections. REM is when your eyes quickly move back and forth under your closed eyelids. NREM means your eyes aren’t moving rapidly (Feriante, 2018). 

The first three stages of sleep are NREM sleep, and they take about 75–80%of each sleep cycle. In these stages, your body and muscles relax; your heart rate, breathing, and brain waves slow down; and your temperature drops. The fourth stage is REM sleep and takes up about 20–25%of the sleep cycle. REM sleep happens towards the end of each cycle, with the first REM phase occurring about 90 minutes after you’ve fallen asleep. (Feriante, 2018).

REM sleep is where you consolidate your memories and have the most vivid dreams. During REM sleep, your body also goes through a temporary form of paralysis, called atonia.

Scientists theorize this paralysis is a protective measure, so we don’t act out our dreams. Usually, atonia ends when we come out of REM and either go into another sleep cycle or wake up, so we are never really aware that atonia happens. With sleep paralysis, though, you may experience atonia and the vividness of REM dreaming even though you’ve woken up (Feriante, 2018).

Sleep scientists categorize sleep paralysis as a parasomnia or abnormal behavior while sleeping. It's called REM parasomnia because it happens during the REM cycle (Farooq, 2020).

There is no clear data on the exact cause of sleep paralysis. Scientists and researchers do not know if sleep paralysis is a side effect of a sleep disorder or if sleep paralysis is another category of sleep disorder altogether. More research is needed to figure out if there is a single cause (Denis, 2018).

Currently, researchers and scientists know certain factors may put you at risk for an episode of sleep paralysis.

Your sleeping patterns

Sleep disorders or any disturbance of your circadian rhythm may put you at higher risk for sleep paralysis. If you are a shift worker or have been diagnosed with shift work sleep disorder, or experience jet lag, you may experience an episode of sleep paralysis. Some people who have nighttime leg cramping may also have an episode (Denis, 2018). 

Your family history

If anyone in your family has sleep paralysis, you may be more prone to having these episodes. People with African and Asian ancestry seem to have higher rates of sleep paralysis (Olunu, 2018).

Your physical and mental health

People with an underlying medical condition are more likely to have episodes of sleep paralysis. Post-traumatic stress disorder (PTSD) or having traumatic experiences like physical or sexual abuse make you more prone to sleep paralysis episodes. People with panic disorder and anxiety disorders have a higher chance of having an episode (Singh, 2018). 

Other factors that make it more likely to have sleep paralysis episodes include: People who have an active and vivid imagination, daydream frequently, or have a habit of disassociating—having an out-of-body experience (Denis, 2017). 

The main symptom of a sleep paralysis episode is atonia, where you’re unable to move your body. You are awake and can feel this temporary paralysis.

These episodes last from a few seconds to up to 20 minutes. The average length of a sleep paralysis episode is about seven minutes. These episodes end by themselves. Sometimes, if another person touches or speaks to you when you have a sleep paralysis episode, it can end much faster (Sharpless, 2016). 

About 75% of sleep paralysis events have accompanying hallucinations that don't resemble normal dreams (Denis, 2018b). These hallucinations can be divided into three distinct types (Denis, 2018):

• Incubus hallucinations, also known as chest pressure hallucinations, make you feel like you are suffocating. These usually accompany intruder hallucinations.

• Intruder hallucinations are where you feel a frightening or dangerous person, creature, or presence is with you in your bedroom. Some people may believe they see ghosts, aliens, or a monster-type presence with them. 

• Vestibular-motor, also known as VM hallucinations, is where some people experience an out-of-body experience or feel like they're flying.

Sleep paralysis episodes can feel terrifying, especially when the inability to move and frightening hallucinations happen together. Dozens of cultures describe episodes of sleep paralysis. In some cultures, interpretation of these dream-like sleep paralysis episodes can be pleasant or even blissful. However, close to 90% of people who have a sleep paralysis episode find them scary (Olunu, 2018).

What are the effects of sleep paralysis on my body?

Some people find they have excessive daytime sleepiness after having an episode of sleep paralysis. But other than that, sleep paralysis is a benign condition that doesn’t cause any severe health problems. However, close to 10% of people with recurrent sleep paralysis or very frightening hallucinations may develop anxiety about going to sleep and have trouble sleeping or getting enough sleep (Farooq, 2020). 

Most people don’t realize that sleep paralysis is relatively common. If you find you keep having sleep paralysis episodes or develop anxiety about them, please see your healthcare provider.

They will ask you for your complete medical history, including any mental health issues. They will want to know if you take any medications, supplements, and over-the-counter drugs, including sleep medications. They will want to know when the hallucinations began, how often they happen, and how long they last.

You may be asked to keep a sleep diary to see your sleeping patterns. This data may help identify an underlying health condition like narcolepsy or obstructive sleep apnea. There is a connection between sleep paralysis and sleep disorders, so initial treatment may focus on improving your sleep quality (Farooq, 2020). 

If sleep paralysis is causing anxiety, you may benefit from cognitive behavioral therapy for insomnia (CBT-I). This type of talk therapy helps you identify negative feelings and thoughts about sleep and gives you tools to sleep better. CBT-I therapy is short-term talk therapy typically lasting for six weeks with a one-hour session every week. One study shows that focused attention meditation done together with muscle relaxation therapy can help minimize the chances of having a subsequent episode of sleep paralysis (Jalal, 2016).

You may benefit from modifying your sleep habits or adopting best sleep hygiene practices to lower your chances of experiencing sleep paralysis.

• Create a sleep schedule where you go to bed and wake up at consistent times, even on weekends.

• Set up your bedroom for relaxation and sleep: have a comfortable mattress, pillow, and bedding, and blackout curtains to block light for better sleep.

• Keep your sleeping environment at a cool temperature.

• Stop drinking caffeine and alcohol several hours before bed.

• Stop using screens (phone, tablet, or television) at least a half-hour before bed.

If you’ve had an episode of sleep paralysis, you may be frightened that you will experience it again. Thankfully, there don’t seem to be any long-term health consequences of this type of sleep disorder. However, if you keep having episodes, feel anxious, or have excessive daytime sleepiness, please seek medical advice.

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Current version

June 14, 2021

Written by

Tobi Ash, MBA, RN, BSN

Fact checked by

Steve Silvestro, MD

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About the medical reviewer

Steve Silvestro, MD, Ro

Dr. Steve Silvestro is a board-certified pediatrician and Associate Director, Clinical Content & Education at Ro.