Sleep paralysis: Wide-awake brain, snoozing body

(Credit: Getty Images)

Your eyes begin to open after a good night of sleep, but something feels weird. You try to rub the tiredness out of your face but can’t lift your arms. In a panic you try to take a deep breath but can’t draw air. You can’t sit up, and you may even see a shadow in the corner of the room. What’s going on? A frightening phenomenon known as sleep paralysis.

Sleep paralysis is an episode where your brain tells the body that you’re still in the rapid eye movement (REM) stage of sleep in which the limbs are temporarily paralyzed (to prevent physically acting out dreams), heart rate and blood pressure rise, and breathing becomes more irregular and shallow. This is the stage of sleep where your most vivid dreams occur, which can explain why some people may hallucinate during sleep paralysis.

“Sleep paralysis is a frightening event,” says Steven Bender, director of the Center for Facial Pain and Sleep Medicine and clinical assistant professor with the Texas A&M College of Dentistry. “Someone is awake, but they have no control of their body and might possibly even see things that aren’t there because their brain still thinks it’s in REM sleep.”

Sleep paralysis differs from dreaming and night terrors mainly due to the fact that the brain is awake, even if it hasn’t told the body just yet.

“When people have a nightmare, they sleep, have a dream, and then wake up,” Bender says. “When they’re experiencing sleep paralysis, they may have a dream when they are already awake.”

Dying for more sleep? How insomnia may kill you

Spells of sleep paralysis last only a few moments—at most a couple minutes—and typically only occur when falling asleep or waking up. In addition to muscle atonia, someone experiencing sleep paralysis can have the experience of dreaming with the added involvement of being conscious and aware of their surroundings.

“People who experience sleep paralysis can have vivid hallucinations because they are dreaming,” Bender says. “People have felt like they’re levitating or that someone is in their bedroom or a variety of other strange experiences—like alien abductions.”

REM sleep occurs in cycles of about 90 to 120 minutes throughout the night, and it accounts for up to a quarter of total sleep time in adults—particularly towards the latter end of sleep.  Because rapid and irregular breathing occurs in REM sleep, people who experience sleep paralysis may struggle to breathe properly, which can feel like suffocation.

Sleep paralysis may happen more often than you’d think, affecting seven to eight percent of the population, and is more frequent in African-Americans, young adults, and women. Napping during the day or being on a phone or laptop in bed can potentially increase risk.

People who have narcolepsy, a chronic sleep disorder that causes overwhelming drowsiness, or other sleep disorders have an increased risk for sleep paralysis. Other mental health disorders, such as depression and anxiety, have also been linked with greater chances of sleep paralysis.

Source: Texas A&M University