Paralyzed at Night: Is Sleep Paralysis Abnormal?

Contributed to by Sean Mandell & Kevin Morton, Winter 2010

Have you ever woken up from sleep only to discover that you cannot move a muscle? With the exception of your eyes and breathing, you find yourself virtually frozen in bed. Sleep paralysis can be a frightening situation, but rest assured that it is not uncommon and typically not a cause for concern.

Sleep paralysis occurs when your body becomes paralyzed right after you fall asleep or as you wake up. It can sometimes be a sign of the sleep disorder narcolepsy, in which a patient falls asleep (straight into REM sleep) unexpectedly at various times during the day, though it happens quite frequently in even the most normal of sleepers.

Generally, if you experience left-over sleep paralysis when coming out of sleep it is not a cause for concern. To understand why this is, lets take a look at the mechanisms that cause this phenomenon.

Causes of Sleep Paralysis

What causes sleep paralysis? Well, every night during REM (Rapid Eye Movement) sleep, the stage of sleep during in which you dream, the body shuts down virtually all muscle activity to prevent you from acting out your dreams. Your brain is very active as you dream, as you might imagine. The only thing that prevents your body from moving to carry out the scene your brain is living is a mechanism that kicks in to paralyze it.

This mechanism is referred to as atonia, or REM sleep paralysis. Occasionally, this mechanism malfunctions in some people in what is known as REM sleep behavior disorder (or RBD). People with RBD often thrash around (or even walk and sometimes even drive!) in a manner that corresponds with what's happening in their dream world. You can learn more about this and some of the complexities this brings up here.

On the other end of the spectrum, occasionally this REM atonia can work too well and trickle over into the waking state for a short period. It is not uncommon to be temporarily paralyzed upon waking up from a dream if the brain is slower than normal to let the muscles be reactivated. If this is the case, and lingering sleep paralysis does not occur with extreme regularity, then it is completely harmless. Some people's bodies just take a bit longer to disarm their atonia.

However, experiencing sleep paralysis right when you fall asleep or wake up can also be a sign of narcolepsy, if it occurs on a frequent basis.

Narcolepsy is a disorder affecting over 250,000 Americans characterized by uncontrollable attacks of REM sleep (and therefore the REM atonia that comes with it) during the day. These spells are known as cataplectic attacks and are usually brought on by intense emotions. Narcolepsy also involves abnormal REM processes, such as dreaming immediately after falling asleep. (Normally, a person will not start dreaming until being asleep for at least an hour.)

Sleep paralysis at the beginning of sleep, therefore, can indicate an abnormal REM process underlying narcolepsy. Sleep paralysis may be harmless if it is very infrequent, but if in doubt, consider consulting a doctor or (preferably) a sleep specialist to get tested for narcolepsy, especially if the sleep paralysis is accompanied by other signs of narcolepsy.

Have You Ever Experienced Sleep Paralysis?

Have you ever woken up to sleep paralysis before? It can be quite an experience!

Share your story with the world below--your insight could aid others who can relate to what you have experienced.

Click on the links below to read stories of others that have experienced sleep paralysis. They were all written by other visitors to this page, just like you.