Sleep paralysis is a freaky phenomenon that has inspired ghost stories and alien abduction conspiracies. Fortunately, there's a scientific explanation for why it happens, and also ways to prevent it.
You wake up out of a hazy sleep and you can’t move your body—you’re completely paralyzed! You also have this oppressive feeling in your chest, as if something heavy is sitting on it, and an eerie sense that someone's in the room with you. Your heart pounds, and everything spirals, becoming more and more unreal as you scream silently inside.
Is this a great horror movie scene, or something more sinister?
What is sleep paralysis?
Different cultures have explained this frightening experience in various ways. In Brazilian folklore, a crone with long fingernails lurks on roofs and tramples on sleepers’ chests. In Japanese mythology, vengeful spirits come to suffocate their enemies while they sleep. For Canadian Eskimos, it’s the spells of shamans that paralyze the sleeper while giving them hallucinations. In contemporary American culture, sleep paralysis has taken on the mythology of alien abductions—sleepers wake up unable to move, seeing or feeling the presence of aliens in the room while experiencing zapping sensations and a feeling of suffocation.
But it turns out all of these symptoms describe sleep paralysis, a sleep disorder (or symptom of a sleep disorder) that temporarily alters a person’s mobility, perception, thinking, and emotional state during the transition between sleeping and waking.
Sleep paralysis is a surprisingly common experience—almost 8% of the general population has experienced it at least once. But if you’re a student or someone with a psychological diagnosis, your chances of experiencing it go up to almost 1 in 3.
But rest assured, sleep paralysis is usually harmless, especially if it only happens rarely. But why does it happen at all, when should you worry about it, and how can you prevent sleep paralysis?
Why does sleep paralysis happen?
The “paralysis” part of sleep paralysis actually happens every night when you sleep, even though you're usually not aware of it. That’s because of a special type of sleep called rapid eye movement or REM sleep.
During REM, your brain is very active—the electrical signals from the brain look almost like the signals it has when you’re awake.
REM sleep is often referred to as a stage of sleep that takes up 20-25% of your typical night. It occurrs in a few chunks, mostly during the second half of the night. During REM, your brain is very active—the electrical signals from the brain look almost like the signals it has when you’re awake. This is also when most dreaming happens, along with a lot of emotional processing that the brain does behind the scenes.
But, importantly, your body is immobilized during REM. Other than the eyes moving around a lot (hence “rapid eye movement”), your muscles lose tone. This is your body's way of preventing you from acting out your dreams.
So, every night during REM, you are “paralyzed” while you hallucinate and process emotions. Usually, you don’t realize this is happening because you're asleep. But sometimes, the veil between sleep and wake becomes thin and you find yourself straddling both wakefulness and REM sleep at the same time.
Every night during REM sleep, you are 'paralyzed' while you hallucinate and process emotions.
Suddenly, you’re awake and paralyzed while you hallucinate and process emotions. Often, this also comes with a racing heart, fear, and sometimes even a feeling of impending death. The sensation can last a few seconds to a few minutes. Those seconds and minutes can feel like a long time when you’re scared out of your wits. No wonder people around the world have mistaken sleep paralysis for a demonic attack!
What makes some people more prone to sleep paralysis?
The good news is that sleep paralysis is usually harmless. It’s simply a temporary SNAFU in the sleep-wake brain systems that failed to transition you completely from sleep to wakefulness. If it only happens rarely to you, you don’t need to worry.
For some people, sleep paralysis happens more regularly. For example, those with narcolepsy, a sleep-wake disorder that disrupts a person’s ability to stay awake, sleep paralysis can be part of their regular experience. Often, narcolepsy comes with not only sleep paralysis when waking, but also hallucinations as one is falling asleep (called “hypnagogic hallucinations”), suddenly falling asleep or losing muscle tone during the day, and having poor nighttime sleep quality. If you experience these symptoms, you should ask your doctor for a referral to a sleep study.
Anxiety and trauma-related disorders
Having an anxiety disorder such as panic disorder, generalized anxiety disorder, social anxiety, or death anxiety is associated with a higher risk for sleep paralysis. Having experienced trauma or having post-traumatic stress disorder (PTSD) also makes a person more likely to have sleep paralysis.
Being a student
College students have about a 4-fold higher risk of experiencing sleep paralysis. It’s not clear whether this is because people in their late teens and early twenties are more prone to sleep paralysis or because students have lifestyles that make sleep paralysis more likely. For example, students are more likely to pull all-nighters studying, have periods of high stress, binge drink, or use recreational drugs, all of which can disrupt sleep and cause sleep paralysis.
How to prevent sleep paralysis
If you have a medical or psychiatric disorder that makes sleep paralysis more likely, such as narcolepsy or an anxiety disorder, getting treatment for that disorder is the most important thing to do. But if you don’t have one of these other disorders—or you’re already getting treated for a disorder like anxiety, for example—but you still experience sleep paralysis, it may be due to general disruptions to your sleep. Here’s what to do to improve your sleep and decrease the chances of having sleep paralysis:
1. Keep a consistent sleep-wake schedule and get enough sleep
Often, sleep paralysis happens because you’ve either been sleep deprived or your sleep schedule has been messed up. This may be due to a phenomenon called “REM rebound.” Remember REM sleep, the type of sleep where we're immobile but dreaming? If the brain repeatedly does not get enough REM sleep, it’s going to be deprived of this important sleep process. The next time you sleep, your brain will try hard to make up the deficit by jumping into REM more quickly than usual and producing more intense brain activity. This makes it more likely for you to have an incomplete transition between REM and wake, and therefore more likely to have sleep paralysis.
If the brain repeatedly does not get enough REM sleep, it’s going to be deprived of this important sleep process.
This REM rebound can happen when you’re consistently not getting enough sleep, or your circadian rhythm is thrown off by jet lag, shift work, or often, not sticking to a regular sleep-wake schedule.
So start by deciding on a consistent time you can get up each morning (including weekends, with no more than an hour’s wiggle room to sleep in) and set an alarm for that time. Get up with the alarm even if you didn’t sleep well that night, and go to bed in the evening when you’re feeling sleepy. After a few days or weeks of staying consistent with your wake-up time, your body will adjust and make you sleepy at around the same time every night.
For this sleep regulation process to work, you'll need to avoid doing anything too stimulating (like playing video games) before bedtime.
2. Practice relaxation or meditation
According to one recent study, relaxing the body and mind may reduce or even eliminate sleep paralysis. This is based on the idea that sleep paralysis and panic symptoms form a vicious cycle in the moment, and that shifting your attention away from the frightening hallucinations and body sensations will interrupt this cycle and get you back to relaxed sleep, or at least make sleep paralysis less scary.
This brings the relaxation system online and dampens the fight-or-flight system.
The technique involves having some pleasant internal thing to focus on during a sleep paralysis episode, such as a nice memory, and consciously trying to relax your muscles. This brings the relaxation system online and dampens the fight-or-flight system.
3. Limit alcohol and drugs and review your medications with your doctor
There are some medications that disrupt REM sleep, including many antidepressant medications and medications prescribed for insomnia. Other substances, such as alcohol, may disrupt sleep and contribute to REM rebound. Generally, it’s a good idea to minimize alcohol and recreational drugs, especially in the evenings. It’s also worth reviewing your medications with your doctor to see if one of them may be contributing to sleep paralysis.
4. Get cognitive behavioral therapy for recurrent isolated sleep paralysis (RISP)
If you frequently experience sleep paralysis but you don’t have consistently poor sleep, narcolepsy, or medications that disrupt REM, you may have recurrent isolated sleep paralysis (RISP). This just means that you have sleep paralysis much more often than you should, and there is no clear reason for it.
In this case, you may need to have cognitive behavioral therapy (CBT) for recurrent sleep paralysis. This involves a few sessions of skills-based psychotherapy where you learn techniques for disrupting the sleep paralysis episode in the moment, along with relaxation, skills for coping with hallucinations, daytime imagery practice, and healthy ways to think about sleep paralysis attacks that don’t feed into the experience.
It’s not anything supernatural or conspiratorial—nothing to be afraid of in and of itself.
Sleep is supposed to be a sweet, relaxing experience, so it’s not only frightening but also frustrating to have it interrupted by sleep paralysis. But now, you know it’s not anything supernatural or conspiratorial—nothing to be afraid of in and of itself. Just make sure to practice good sleep habits, hone your relaxation skills, and make sure to limit substances that could be messing up your sleep.
And if sleep paralysis happens again, you can cope with the scary sensation by focusing on a pleasant memory or object. When you fully wake up, shake it off and chalk it up to your brain playing with the boundary between sleep and wake. Then you can marvel, like I do every day, at what a profound mystery the human brain is!
Image from Shutterstock (Marcos Mesa Sam Wordley).