In this Sunday’s episode of Keeping Up With the Kardashians, Kendall Jenner revealed that sometimes she wakes up and can’t move. “It’s the scariest thing in the entire world,” the 21-year-old told her sister Kim. “You literally think that you’re never going to be able to move again. You can’t do anything. You're freaking out.”

Sleep paralysis is a very real thing, says Harneet Walia, MD, of the Cleveland Clinic Sleep Center. It can happen as you’re falling asleep or waking up, she explained in an email to Health—and it can be terrifying.

When you’re in the REM stage of sleep where vivid dreams occur, your limbs are immobilized so you don’t try to, say, sprint away from a charging tiger. But if you wake during the REM stage, your body may linger in the land of nod—so you’re conscious, but feel paralyzed.

To make matters worse, you may also feel like you can’t breathe, says Dr. Walia: “Episodes of sleep paralysis can be frightening because the immobility can be associated by a sensation of suffocation.”

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The good news is that sleep paralysis only lasts for a few minutes, and isn’t dangerous, says Dr. Walia. More than 7% of us may experience it at some point in our lives. While it’s most common in people with narcolepsy, it’s also linked to lack of sleep and an irregular sleep schedule, says Dr. Walia.

Good sleep hygiene can help. Make sure you’re catching enough Zs, and try to go to bed and wake up around the same time every day. (For more tips, check out “30 Sleep Hacks for Your Most Restful Night Ever.”) Sleep paralysis usually isn’t treated, says Dr. Walia. But in some cases, it may be worth seeking medical attention.

On KUWTK, Kendall told her mom that she is scared to fall asleep because the episodes keep happening to her. “It almost feels like my heart stops,” she said. And the sleep paralysis seems to feed her anxiety about traveling (which, as a model, she has to do a lot).

 

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If your sleep paralysis is taking a toll on your health or your daily life, talk to your doctor, Dr. Walia urges. He or she may be able to help you manage the problem. And “rarely, medications can be tried,” says Dr. Walia.