August 2020 | Reviewed by: Shelley Hershner, MD and Anne M. Morse, DO
What is sleep paralysis?
Recurrent isolated sleep paralysis is a parasomnia. A parasomnia involves undesired events that occur while you are falling asleep, during sleep, or as you are waking up. A REM parasomnia is one that happens during a transition into or out of REM sleep. Sleep paralysis is a REM parasomnia. It causes you to be unable to move your body at either of the two following times:
- When falling asleep (hypnagogic or predormital form)
- When waking up from sleep (hypnopompic or postdormital form)
Normally your brain causes your muscles to relax and be still in REM sleep. This is called “REM atonia.” This happens to keep you from acting out your dreams. Sleep paralysis occurs when REM atonia happens while you are falling asleep or waking up. Sleep paralysis is “isolated” when it appears without any other signs of narcolepsy or other sleep disorders.
An episode of paralysis may cause you to be unable to speak. It can also make you unable to move your arms and legs, body, and head. You are still able to breathe normally. You are also fully aware of what is happening. An episode can last for seconds or minutes. The episode usually ends on its own. It may also end when someone touches you or speaks to you. Making an intense effort to move can also end an episode. Sleep paralysis may occur only once in your life. It may also happen many times in a year.
It can be very scary when you are unable to move. You may feel anxious and afraid. Some people also hallucinate during an episode. They may see, hear or feel things that are not there. They may even think that another person is in the room with them. These hallucinations may also appear without the sleep paralysis.
Sleep paralysis tends to first appear in the teen years. It then occurs most often when you are in your 20s and 30s. It may continue into your later years. Although the paralysis event may be frightening, it is not a serious medical risk on its own and does not keep you from getting the sleep you need.
Sleep paralysis can be one sign of narcolepsy. Other signs include excessive daytime sleepiness, fragmented sleep, sleep-related hallucinations, and cataplexy. If you are experiencing these symptoms along with sleep paralysis, you should talk to a sleep doctor. Narcolepsy is a serious disorder that requires treatment, and a sleep doctor is best suited to diagnose and treat narcolepsy.