Sleep Paralysis: What Happens When Your Brain Wakes Up Before the Rest of You

Sleep Paralysis: What Happens When Your Brain Wakes Up Before the Rest of You

You wake up—or at least, you think you’re awake—but you can’t move a muscle. You also can’t speak, or scream, which is problematic given the ominous shadowy figure sitting on the end of your bed, moving closer at an agonizing pace.

Sounds like a horror movie, and for sufferers of a phenomenon known as sleep paralysis, it feels like one. Almost every culture in the world has legends of evil supernatural beings terrorizing people while they sleep, and many scientists think that sleep paralysis is to blame. Accounts of night-demons date back to the 10th century, and until the 19th century, hauntings and demonic possessions were widely accepted explanations. Henry Fuseli’s 1781 painting The Nightmare, pictured above, is probably inspired by waking dreams, which were an increasing subject of interest for doctors at the time.

When your body enters deep rapid eye movement (REM) sleep, your brain essentially gives up voluntary control of your muscle movements. This temporary state of near-paralysis occurs to protect you from injury caused by acting out the movements in your dreams. Sleep paralysis occurs when your eyes open and your brain starts to wake up, but your muscular control lags behind for anywhere between a few seconds and a few minutes. This terrifying, half-wakeful state is often accompanied by vivid hallucinations, and in some people, a choking sensation. That’s probably what’s responsible for stories where a malevolent supernatural figure attempts to asphyxiate its victim, as with the demon sitting on the lady’s chest in Fuseli’s painting.

Fortunately, sleep paralysis carries no medical risk, but frequent reoccurrence can be unsettling, to say the least. It’s not clear how common it is—estimates range between 6% and 65% of the general population—and people experience it anywhere from a few times a year to a few times a week. However, we do know that people with disturbed sleep patterns are far more likely to have sleep paralysis, it and that it frequently co-occurs with narcolepsy, a sleep disorder characterized by excessive sleepiness.

So, what should you do if you wake up with a ghostly figure on your bed? Far be it from us to dictate your belief system, but if you take the scientific view, probably nothing, since sleep paralysis is not inherently dangerous. That said, if it’s frequent enough to be distressing, it’s worth bringing up with your doctor. In this case, regulating your sleep patterns by practicing sleep hygiene, and making sure your mattress is a good fit for your body type, will likely help.

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