What Is Sleep Paralysis and What Causes It?

Woman suffering from sleep paralysis is laying in her bed with her eyes open, unable to move.

At a Glance

  • Sleep paralysis is a medical condition in which sufferers are sometimes unable to move and may experience other symptoms when first going to sleep, or on waking.
  • It is a condition which, while not life threatening, is extremely disturbing and frightening when it occurs.
  • There is currently no cure for sleep paralysis, but there are factors which can decrease the risk and steps that can be taken to decrease the likelihood of suffering from sleep paralysis.

While falling asleep or waking from sleep, some people experience a period of a few minutes when they are completely unable to move.

Sleep paralysis is a disorder that affects over seven and a half percent of the population. It can be an extremely disconcerting and even frightening experience. (source)

Described in ancient manuscripts as far back as the 10th century, traditional folklore tales often associate this unusual phenomenon with ghosts and ghouls, and other things that go bump in the night.

Many accounts of experiencing sleep paralysis involve a sensation of something or someone sitting on the chest, and describe a very real feel of pressure on the thoracic and abdominal area.

Thankfully, since medical research began investigating sleep paralysis, we now know that it nothing to do with anything sitting on the chest. There are specific scientific explanations for what happens during sleep paralysis, but scientists have yet to discover the specific causes.

We take a closer look at sleep paralysis, discuss what we know about it, what has been proven in research, and what medical treatment of sleep paralysis involves.

What Is Sleep Paralysis?

Sleep paralysis is a condition that occurs when moving through different stages of sleep. It has two basic types – hypnagogic, or predormital sleep paralysis, and hypnopompic, or postdormital sleep paralysis.

Predormital sleep paralysis happens as a person is falling asleep. Postdormital sleep paralysis occurs as a person is waking from sleep. In both cases, sleep paralysis is a conscious state where the person is unable to move any part of their body.

What Happens During Sleep Paralysis?

Some observational research studies have found that episodes of sleep paralysis can last anywhere between a few seconds and a few minutes. In addition to not being able to move, other commonly reported symptoms are:

  • Feeling awake and conscious
  • Auditory and visual illusions

Less commonly reported symptoms are:

  • Overpowering feelings of fear or anxiety
  • Shallow, labored breathing
  • A sense of something or someone being present in the room
  • A feeling of pressure on the body
  • A choking sensation
  • Strange smells in the room
  • Feelings of floating or being moved
  • The sound of approaching footsteps
  • Animal noises (source)

The Sleep Paralysis Project has produced a great video to explain sleep paralysis here.

Historically, prior to research tools being developed that were able to measure brain activity, sleep was thought to be a period in which much of the activity of the brain ceased to allow the body to rest.

However, we now understand that this is incorrect. Research indicates that at some points, the brain is more active in sleep than during waking hours. (source)

The Sleep Cycle

Woman's hand on her patterned light sheets.

When we sleep, the body goes through various sleep stages. The sleep cycle begins with non-rapid eye movement (NREM) phases, the first two stages of which are light sleep, from which the body can easily be woken.

The third stage of NREM sleep is a deep sleep phase, where the body begins the processes of healing, repairing and refreshing the various systems.

Research has observed that the body then ascends into a light sleep stage before it enters the rapid eye movement (REM) phase, another deep sleep phase where dreams occur. This cycle continues throughout the night, with the REM phases becoming progressively longer as sleep continues.

How alert the body is when we awake from sleep depend on the sleep phase the body is in when waking occurs. With the constraints of daily life, very few people have the luxury of waking naturally from sleep; if we did, we would experience waking in a phase of light sleep.

Most of us, however, are awoken by alarms, so that we are not late for work or school. This means that we may be in a phase of deep sleep when the alarm goes off. As a result, the body is not ready for action, and even those who have no sleep disorder wake up feeling disoriented and sleepy.

What Causes Sleep Paralysis?

The exact causes of sleep paralysis are not fully understood. The onset of symptoms tends to happen in adolescence.

Research has linked sleep paralysis with a number of different factors which influence its prevalence. Substance abuse, stress, anxiety and trauma – including post-traumatic stress disorder – our physical health, personality and beliefs have all been identified as influencing whether or not a person is likely to suffer from sleep paralysis.

The quality of sleep, and whether or not a person suffers from any sleep disorders are also significant factors in sleep paralysis. For example, it has been closely linked with narcolepsy, a condition in which is characterized by an overwhelming need for sleep, and sudden, unexpected episodes of sleep. (source)

Sleep paralysis is thought to occur when the body is unable to make smooth transitions through the different stages of sleep cycle – from light sleep to deep sleep phases in predormital sleep paralysis, and from deep sleep to light sleep in the postdormital condition.

As a result of unusual sleep phase transitions, sleep paralysis results in a situation where a phase of REM sleep coincides with waking. During normal REM sleep, the brain switches off muscle activity to stop us from acting out the dreams we experience.

The brain takes a short time to readjust from deep sleep to waking, and activate our movement systems, hence the paralysis. Sufferers experience a period of REM sleep even though they are awake.

This means that dreams get mixed up with reality. Being awake during REM sleep makes everything feel very real, even though it isn’t. (source)

The Bad News

Sleep paralysis can be extremely frightening – especially the first time it occurs. This can cause high levels of anxiety and feelings of panic. It can be particularly concerning for sufferers because it happens at times when they are not fully awake

There is currently no cure for sleep paralysis. Treatment focuses on avoiding the onset of the condition and managing the symptoms when they occur.

The Good News

The good thing about sleep paralysis is it is temporary. The period of not being able to move usually only lasts for a few minutes before the brain switches the muscles and movement systems on again and resumes normal function.

Another positive point is it is not a life threatening condition. Although it is distressing and frightening to experience sleep paralysis, it is still possible to breathe and the body maintains all of the normal functions as it would in the usual phases of REM sleep.

Although there is currently no definitive cure for sleep paralysis, research to increase our understanding of this condition is continuing. Medical researchers continue to trial different clinical methods and evaluate their impact on sleep paralysis.

Treatment for Sleep Paralysis

Messy white sheets on a bed.

There is currently no way to cure sleep paralysis. Research indicates that sleep paralysis decreases with age, and medical help to manage symptoms is concerned with reducing risk factors and following healthy sleep habit advice.

Healthy sleep habits include:

Following a Consistent Sleep Schedule

Going to bed at the same time each night, and waking at the same time each morning can decrease the likelihood of episodes of sleep paralysis.

A Relaxing Environment

Sleeping in a calm, relaxed environment can decrease episodes of sleep paralysis. Decluttering your bedroom and using low level lighting can help to create a tranquil atmosphere.

Lower Temperature

Keep the temperature of your bedroom on the cool side, but make sure it’s not too cold.


Taking regular exercise – particularly something you enjoy and are familiar with, rather than taking up a new sport or activity – can help to improve sleep patterns. Leave a gap of several hours between exercise and bedtime.

Unhealthy Habits

Avoid consuming alcohol, caffeine, eating a large meal and smoking immediately before sleep. All of these can decrease the quantity and quality of sleep.

Other Methods

Scientific research, however, still continues to search for solutions to the problems of sleep paralysis. Some studies are investigating some types of meditation and specific methods of relaxation as potentially helpful in treating sleep paralysis.

One research paper suggests that a four stage process of self-reassurance, reinforcement of the belief that the condition is temporary and benign, inwardly focused meditation in which the individual directs all their attention to an emotional thought or feeling of major significance and a muscle relaxation program may be effective in treating sleep paralysis.

The researchers advocate the use of this method as a training program to help sufferers prepare for an attack by practicing the techniques at a time when they are not experiencing an episode of sleep paralysis, to better prepare themselves to manage their symptoms when they occurred.

They suggested that this approach may reduce some of the symptoms which occur during an attack, shorten the episode of sleep paralysis and result in less frequent and less severe periods of sleep paralysis in the future.

This method of treatment for sleep paralysis has been likened to a particular type of therapy known as exposure therapy. This has proven successful in conditions such as phobias, and is thought to provide more control over the mind and prevent the fear produced by the phobia to take over.

When this approach has been used in individual cases of sleep paralysis, sufferers have reported that the technique helped them to reduce hallucinations, become more relaxed and reduce fear. However, researchers note the need for more extensive clinical trials to substantiate their initial findings. (source)

Tips for Managing Sleep Paralysis

Woman sleeping on her stomach in a grey shirt, on her white sheet, in her bed.

The following advice can help to avoid or reduce the frequency of sleep paralysis episodes:

Try not to sleep on your back. Research indicates that sleep paralysis occurs more frequently in back sleepers, so try to adopt a different sleeping position.

Make sure you get enough sleep every night. Research indicates that sleep paralysis is more likely to occur when a person is sleep deprived. Most adults need between seven and nine hours of sleep each night.

It’s also important to try to relax your muscles during sleep paralysis, trust that the episode will pass, and give the brain time to readjust and switch on the muscles rather than trying to fight against the paralysis.

Keep reminding yourself that sleep paralysis is a temporary problem which is going to resolve itself. This will help to reduce feelings of anxiety, fear and panic.

If you experience hallucination or a feeling of someone or something being in your room, try to reassure yourself that no matter how real things appear to be, you are safe and there is no actual threat.

Seek advice from your doctor, who may be able to prescribe medication to help. Your doctor will also be able to inform you of any new types of treatment which may have become available.

Final Thoughts on Sleep Paralysis

Sleep paralysis is a very real and alarming sleep disorder. It occurs when a person wakes during a phase of REM sleep, and the REM state continues after waking, and causes some extremely disturbing symptoms.

While medical experts don’t fully understand why sleep paralysis occurs, many factors which increase the risk of sleep paralysis have been identified.

Current treatment methods focus on reducing the probability of episodes of sleep paralysis by promoting good sleeping habits and managing episodes by trying to stay calm and rational to reduce fear and anxiety. There is currently no cure for sleep paralysis.

Some newer methods of managing sleep paralysis are investigating the possibility that training the body and mind to prepare for sleep paralysis helps to reduce symptoms, and research regarding this is on-going.

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