What Causes Sleep Paralysis and How Can It Be Avoided?

Triggers Include Sleep Deprivation, Narcolepsy, and Sleep Apnea

Causes of sleep paralysis include sleep deprivation, narcolepsy, and sleep apnea and it can be avoided
Causes of sleep paralysis include sleep deprivation, narcolepsy, and sleep apnea and it can be avoided. Cultura/Frank van Delft/Riser/Getty Images

Sleep paralysis is a relatively common experience—up to one in four individuals will experience it unintentionally at one point or another. It occurs when the features of rapid eye movement (REM) sleep intrude into wakefulness, leading to muscles that are unable to move, impaired breathing, and features of vivid dreams like fear and hallucinations. This disconnect between the brain and body's muscles can cause terrifying symptoms.

What are the causes of sleep paralysis? Are there things you can do to avoid experiencing it? There may be some factors that play into sleep paralysis that are beyond your control, but some self-induced behaviors may potentially trigger an episode of sleep paralysis in the right situation. By learning how certain causes can potentially lead to sleep paralysis, you may be better able to avoid it.

Sleep Paralysis as an Extension of the Dream State

Sleep paralysis is simply an extension of the dream state (called REM or rapid eye movement sleep), so it is technically harmless. However, it is not something people seek to repeat once they experience it, as it can be unpleasant. People experience inability to move, speak, or control their body, despite being conscious and wanting to. It is sometimes accompanied by hallucinations, which add to the disagreeable nature of the situation.

Understanding the Causes

The causes of sleep paralysis are surprisingly mundane, despite the elaborate explanations given by some people.

To better understand what sleep paralysis is, imagine there are two states of consciousness: being asleep and being awake. There is normally a transition period between these states. Elements of consciousness may be preserved—such as an awareness of your environment—while aspects of sleep may begin (such as dreaming).

Typically, this transition is brief and uneventful. However, a prolonged or disrupted transition may predispose you to the unusual experiences of sleep paralysis.

Regulating and Disrupting REM

In particular, sleep paralysis is believed to relate to a problem regulating REM sleep. It is during REM that our body is paralyzed so that we are unable to act dreams out. This muscle relaxation, called atonia, may sometimes occur while you are awake. As such, you will be unable to move, even if you are conscious. This is one of the common features of sleep paralysis.

Clearly there are certain triggers of sleep paralysis. It often occurs during periods of sleep deprivation and stress. Many people experience it when their sleep schedule is disrupted, no matter the reason. Those with shift work sleep disorder may be at increased risk. If sleep is attempted during the day, it is more likely for interruptions of sleep to occur.

In addition, it is possible to trigger sleep paralysis experimentally by disrupting REM. In a controlled environment (such as a sleep study), this could be attempted—and has been shown to incite the phenomenon.

Psychiatric Disorders

There also appears to be a strong association with psychiatric disorders like anxiety and depression.

The use of alcohol or other drugs may also provoke an attack of sleep paralysis. For some people, a family history of sleep paralysis becomes evident, though a genetic cause of the condition is not known.

Sleeping Position

Most people with sleep paralysis report that it occurs when they are sleeping on their backs (a supine sleeping position). However, less frequently, others have reported it occurring when sleeping on their stomachs or sides as well.

Timing

The vast majority of people suggest that sleep paralysis happens while falling to sleep (a hypnagogic phenomenon), yet it can also occur when awakening from sleep.

It typically occurs at night, but it has also been known to occur during daytime naps.

Other Sleep Disorders

Sleep paralysis can also occur in association with other sleep disorders that fragment sleep, including obstructive sleep apnea and narcolepsy. Sleep apnea is often worsened by being on one's back and in REM sleep, so other symptoms such as snoring and waking to urinate may suggest a need for testing.

With symptoms such as sleepiness, hallucinations, and cataplexy, it might suggest the sleep disorder called narcolepsy. Treatment of these conditions may reduce the frequency of sleep paralysis episodes.

How to Avoid Sleep Paralysis

If these are some of the causes of sleep paralysis, how can you avoid it? Perhaps the most important thing you can do is to follow the better sleep guidelines. It is necessary to keep a regular sleep schedule, ensure that you get adequate sleep and avoid any of the above triggers that you have identified as being important for you.

Unscientific Explanations of Sleep Paralysis

Sleep paralysis has occurred throughout recorded history, and there are countless examples in literature and art of the phenomenon. In some parts of the world, the condition is called the "old hag."

Religion

Many people describe the experience in religious terms. Some might blame a ghost, demon or devil as the cause. The terrifying elements of sleep paralysis are easily ascribed to a malevolent presence. Others suggest it is due to aliens. There is no scientific evidence for such beliefs.

Medical and Mental Problems

Others worry that another medical or mental-health problem may be to blame. The list of potential medical maladies that might explain the experience of sleep paralysis is diverse, ranging from seizures to heart attacks to strokes. Some even think (at least briefly) that they have died. Still other people worry that they have gone insane and do not discuss it because they are worried how others might react to their experience.

The episode of sleep paralysis is self-limited without lasting consequences, and so these explanations are proven to be false.

Dreams and Nightmares

Finally, some people worry that sleep paralysis is just a dream or nightmare. This may actually be the closest to the truth. As described above, sleep paralysis occurs when there is a breakdown between the states of consciousness and sleep, when our dream state intrudes upon our wakefulness.

Fortunately, many people are reassured by a better understanding of the phenomenon of sleep paralysis, so that if it recurs they know how to interpret the experience and can more easily tolerate it until it inevitably ends.

A Word From Verywell

For most people, sleep paralysis occurs rarely, but if it occurs more frequently and you find it particularly bothersome, you may wish to speak to your doctor for a referral to a board-certified sleep medicine physician. Treatment of narcolepsy or sleep apnea, if present, may be helpful.

Even if your sleep paralysis occurs in isolation, if it has become disruptive to your life, treatment options are available.

Sources:

McCarty, D.E. et al. "A case of sleep paralysis with hypnopompic hallucinations." Journal of Clinical Sleep Medicine. 2009;5(1):83-84.

Morton, K. "Paralyzed at Night: Is Sleep Paralysis Normal?" Stanford Sleep & Dreams. 2010.

Takeuchi, T. et al. "Factors related to the occurrence of isolated sleep paralysis elicited during a multiphasic sleep-wake schedule." Sleep 2002;25:89-96.

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