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Waking up and being trapped within your own body sounds like a nightmare. Experts explain sleep paralysis symptoms, causes, and treatments—and reveal that it's more common than you probably realize. 

March 14, 2017

Picture this: You're curled up in bed, light streaming through your windows, and you're ready to roll over and start your day—but for a few terrifying moments, you can't move. Your mind is awake and your eyes can see, but it's as though your body is still sleeping.

This phenomenon is called sleep paralysis. It can be frightening, and it's more common than you may realize: “About 40% of the population has had at least one episode of sleep paralysis,” says Clete Kushida, MD, PhD, medical director of the Stanford Sleep Medicine Center in Redwood City, California.

Here’s more information about what's really happening to your body when you wake up and can't move. Plus, experts explain the deceptively simple way to prevent sleep paralysis.

It happens when you're waking up or falling asleep

Sleep paralysis occurs when you’re in a borderline state between sleep and consciousness as you’re dozing off or waking up, says Dr. Kushida. Researchers don’t understand why this temporary loss of voluntary muscle control happens. “One theory is that there’s some crossover with rapid eye movement (REM) sleep, also known as dream sleep,” says Neil Kline, DO, a sleep disorder physician in Lancaster, Pennsylvania and a representative of the American Sleep Association. “During REM sleep we are muscle atonic, which means we’re essentially paralyzed. It’s believed to be an evolutionary action that occurred to protect us from hurting ourselves while we’re dreaming.”

Hallucinations are usually involved

Nightmares are scary enough when you're fully asleep; imagine having one with your eyes open. This happens to three quarters of people with sleep paralysis, according to Dr. Kushida. “These hallucinations can be anything from feeling something on your skin, hearing something, seeing something, or feeling like someone is there in the room with you or like you’re levitating,” he says. Yikes.

Sleep paralysis doesn’t last long

Luckily for those experiencing it, sleep paralysis usually passes within seconds or minutes, Dr. Kushida says. Still, it can feel like an eternity.

It can happen to anyone

“Gender doesn’t appear to play a role,” says Dr. Kushida. It usually starts in teenagers and young adults (20s and 30s) but may continue later in life, he says. “It has been shown to run in families as well,” he adds.

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Skimping on sleep puts you at risk

Sleep paralysis is more common in people who are sleep deprived. “The best advice for avoiding sleep paralysis is to make sure you get enough total sleep time,” Dr. Kline says. “With the amount of distractions and societal demands, sleep deprivation has become a significant problem for all age groups.” On average, most adults need seven and a half to eight hours a night, he says. (Learn more about how much sleep you really need.)

Stress is also a factor

Trying to avoid stress as much as possible or taking steps to minimize stress may help lessen the frequency of sleep paralysis if you’re predisposed to it, Dr. Kushida says.

It may be a sign of another sleep disorder

Sleep paralysis is a symptom of narcolepsy, a sleep disorder that causes severe, excessive daytime sleepiness, Dr. Kline says. It may also be a sign that you have sleep apnea or periodic limb movement disorder, in which your legs twitch or jerk during sleep, Dr. Kushida says.

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A sleep specialist can help

If you’re experiencing sleep paralysis more than a few times a year and it’s affecting your quality of life, see a sleep doctor. Your doc can help you improve your sleep hygiene and schedule, as well as rule out other sleep problems. “By treating the underlying disorder, you decrease the severity of sleep paralysis and might make it go away,” Dr. Kushida says.