Sleep paralysis is a temporary inability to move or speak that happens when you are waking up or, less commonly, falling asleep.
Although you are awake, your body is briefly paralysed, after which you can move and speak as normal. The paralysis can last from a few seconds to several minutes.
Sleep paralysis does not cause you any harm, but being unable to move can be very frightening.
Some people have sleep paralysis once or twice in their life, while others experience it a few times a month or more regularly.
Read about the symptoms of sleep paralysis.
It is normal for your muscles to be paralysed at certain times when you are asleep. Sleep paralysis occurs when the mechanism that causes your muscles to relax during sleep temporarily persists after you have woken up.
Sleep paralysis can sometimes be a symptom of narcolepsy. This is a relatively rare sleep disorder that causes a person to fall asleep suddenly and unexpectedly, disrupting their normal sleep pattern.
Other things that increase your risk of sleep paralysis include:
Read more about the causes of sleep paralysis.
If you have sleep paralysis, your doctor may be able to suggest ways you can improve your sleep.
If your symptoms are linked to another sleep-related condition, such as narcolepsy, your doctor may be refer you to a sleep disorder specialist (see below).
The symptoms of sleep paralysis can often be improved by altering your sleep habits and sleeping environment.
Sleep paralysis often affects people who are sleep deprived, so ensuring you get enough sleep may reduce the number of episodes you have. Most adults need 6-8 hours of sleep each night.
Going to bed at roughly the same time each night and getting up at the same time each morning may also help.
Read more about how to improve your sleep habits.
If your sleep paralysis is particularly severe, see your doctor. They may refer you to a specialist, such as a neurologist.
A short course of [antidepressant medication], may be prescribed to treat severe sleep paralysis.
Read more about treatment for sleep paralysis.
The main symptom of sleep paralysis is a temporary inability to move or talk.
The paralysis usually happens as you are waking up, but it can also sometimes happen when you are falling asleep.
Not being able to move or talk can be very frightening, particularly as you will be completely conscious throughout the experience.
During an episode of sleep paralysis, you may also experience a very real sensation that there is someone else in the room with you.
These type of hallucinations are a fairly common feature of sleep paralysis, although they do not occur in every case.
The length of time that you are unable to move for can vary from a few seconds to several minutes. After this, you will be able to move and speak as normal.
Immediately after an episode of sleep paralysis you may feel unsettled and anxious. However, the condition does not pose a risk to your overall health.
Many people only experience sleep paralysis once or twice in their life. If it happens several times a month or more regularly, it is known as isolated sleep paralysis.
Sleep paralysis is caused when hormones produced by the body to help you sleep do not wear off as you wake up.
This means that you remain temporarily paralysed but conscious.
To understand better what causes sleep paralysis, it is useful to know what usually happens when you are asleep.
Sleep occurs in cycles and each cycle is split into two phases – rapid eye movement (REM) sleep and non-REM sleep.
The brain is very active in REM sleep and most dreams occur at this stage of sleep. Also, during REM sleep the body is paralysed, apart from the movement of the eyes and diaphragm (the main muscle used in breathing). The paralysis is thought to occur to prevent you acting out the actions in your dreams.
Sleep paralysis occurs when the normal muscular paralysis of REM sleep temporarily continues after you have woken up.
Certain factors make you more likely to get sleep paralysis:
Ensuring you get enough sleep and improving your sleeping environment will help if you have sleep paralysis. In severe cases, medication may be recommended.
Sleep paralysis is more common in people who are sleep deprived, so getting enough sleep may help reduce the number of episodes of sleep paralysis. Most adults need 6-8 hours of sleep each night.
Keeping to a regular sleeping schedule, where you go to bed at roughly the same time each night and get up at the same time each morning, can also help.
Tips for improving your sleeping habits include:
If your sleep paralysis is particularly troublesome, you may be prescribed a short course of antidepressant medication, such as a tricyclic antidepressant (TA), typically [clomipramine].
The medication is thought to work by altering the amount and depth of REM sleep. This should prevent the temporary paralysis when you wake up or fall asleep, and it should also help reduce any hallucinations you may have.
You may be advised to take the medication for a month or two to see whether it improves your symptoms.
Possible side effects of TAs can include:
These side effects should ease after 7-10 days as your body starts to get used to the medication. You should visit your doctor if the side effects have not eased after this time.
Read more about the side effects of TAs.
Sleep paralysis can sometimes be a symptom of another sleep disorder called narcolepsy, which causes severe daytime sleepiness and an inability to stay alert for more than a few hours.
Although there is no cure for narcolepsy, the condition can usually be managed with medication.
A number of lifestyle adjustments may also help, including:
Read more treatment advice for narcolepsy.
Gareth Fletcher, 32, regularly had sleep paralysis when he was a teenager. Although it has virtually stopped, he still experiences it very occasionally.
"I first experienced sleep paralysis when I was 16.
"I remember it vividly. I went to bed one night as usual, but at some point I woke up and was unable to move a muscle. I was conscious and aware that I was in my bed, but my entire body was paralysed.
"It may have only lasted a matter of seconds, but the experience was terrifying. There was a ringing noise in my ears that seemed to get louder, and no matter how hard I struggled, I couldn't move. I had a feeling of immense panic, and an urgent need to move my arms and legs.
"Then suddenly I could move again. While this was a great relief, I was still scared as I had no idea what had just happened.
"The same thing happened again a few nights later, and then it began to happen regularly. Often, it would happen a couple of times in the same night.
"I became nervous about going to sleep – worried that every time I went to bed I’d wake up and be unable to move. Even though the paralysis was only temporary, it was very frightening.
"Often, I would wake up suddenly after having a vivid dream. Sometimes this was an unpleasant dream, which made the experience even scarier.
"I didn’t tell anybody about it at first. This was partly because I began to doubt that it was really happening. I thought perhaps I was dreaming it, and although it seemed very real at the time, perhaps it was just a nightmare in which I couldn’t move.
"Also, it happened as I was falling asleep early in the night. By the time I'd woken up in the morning, it didn't seem to matter so much and I tried to forget it had happened.
"Then one day at school, I overheard a friend talking about a documentary he'd seen about this very phenomenon. It was the first time I'd heard the term 'sleep paralysis', and it perfectly described what happened to me – although my friend mentioned that the people on TV had also felt a presence in the room and a pressure on their chest when they woke up, which I hadn't had.
"Knowing that it had a name was a relief. I told my parents about it, and my dad said it happened to him once when he was younger. My mum has since said it once happened to her too.
"My mum then told our doctor, who said it was nothing to worry about and that little was really known about it. The doctor did say she thought it may be linked to stress.
"The sleep paralysis kept happening, but I no longer felt so panicked by it. It was still very unpleasant and I had a desperate need to move every time I woke up, but I just told myself that it was nothing sinister and I’d be able to move in a few seconds.
"And then it stopped happening, almost overnight, when I went to university. It's odd, but it seemed to happen only when I was in my bed at home. After I left, it virtually disappeared.
"It does happen now, but only extremely rarely. It can still be frightening, mainly because of the disorientation you feel when you suddenly wake up and can't move. But knowing what's happening and that it's nothing to worry about makes it bearable, and I'm usually able to relax and get back to sleep quickly."
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.