What are the causes of sleep paralysis?

Sleep paralysis is a condition that occurs when someone is temporarily unable to move or speak as they are falling asleep or waking up. Sleep paralysis happens when a person passes between stages of wakefulness and sleep, and it can last from several seconds to several minutes. Read on to learn more about sleep paralysis, including potential risk factors.

During sleep, the body alternates between rapid eye movement (REM) sleep and non-REM sleep. Most dreams that people remember occur during REM sleep, which is also known as deep sleep. During REM sleep, the eyes continue to move but the rest of the body's muscles are relaxed and remain still. If someone awakes suddenly before the REM cycle has finished, they may be unable to move, speak or open their eyes. This is known as sleep paralysis.

The exact cause of sleep paralysis is not known, but research has identified several risk factors associated with the condition. While sleep paralysis can happen to healthy people, those who have a sleep disorder, such as narcolepsy or obstructive sleep apnea, may be at a higher risk of sleep paralysis. Inadequate sleep may also trigger sleep paralysis. Sleep paralysis is more common for people with irregular sleep schedules, such as those with jet lag as well as night shift workers, since irregular sleep schedules disrupt the body’s day-night cycle.

Increased stress has been associated with sleep paralysis. People with panic disorder or post-traumatic stress disorder appear to be more likely to experience sleep paralysis.

People who sleep on their back also appear to be more likely to experience sleep paralysis.

Improving sleep habits may help avoid sleep paralysis. Some tips for healthy sleep include:

• Going to bed only when tired
• Reducing liquid intake before bed to minimize nighttime bathroom breaks
• Avoiding naps
• Reducing use of alcohol and caffeine, especially in the evening
• Eliminating the use of electronics, such as cell phones, before bedtime

Although sleep paralysis may be frightening, it is generally not harmful. Many people will have at least one episode during their lifetime. However, if it occurs more frequently and affects your sleep or makes you feel anxious, see your healthcare provider. They may be able to identify and address underlying problems that may be contributing to sleep paralysis. Be sure to inform your provider of any medication use. Your provider may also refer you to a sleep specialist for further evaluation.

Clinically reviewed May 2023.