The scientific facts

What is Sleep Paralysis?

Sleep paralysis is a feeling of being conscious but unable to move. It occurs when a person passes between stages of wakefulness and sleep. During these transitions, you may be unable to move or speakĀ  Some people may also feel pressure or a sense of choking. Sleep paralysis may accompany other sleep disorders such as narcolepsy. Narcolepsy is an overpowering need to sleep caused by a problem with the brain’s ability to regulate sleep.

When Does Sleep Paralysis Usually Occur?

Sleep paralysis usually occurs at one of two times. If it occurs while you are falling asleep, it’s called hypnagogic or predormital sleep paralysis. If it happens as you are waking up, it’s called hypnopompic or postdormital sleep paralysis.

 

What Happens With Hypnagogic Sleep Paralysis?

As you fall asleep, your body slowly relaxes. Usually you become less aware, so you do not notice the change. However, if you remain or become aware while falling asleep, you may notice that you cannot move or speak.

 

What Happens With Hypnopompic Sleep Paralysis?

During sleep, your body alternates between REM (rapid eye movement) and NREM (non-rapid eye movement) sleep. One cycle of REM and NREM sleep lasts about 90 minutes. NREM sleep occurs first and takes up to 75% of your overall sleep time. During NREM sleep, your body relaxes and restores itself. At the end of NREM, your sleep shifts to REM. Your eyes move quickly and dreams occur, but the rest of your body remains very relaxed. Your muscles are “turned off” during REM sleep. If you become aware before the REM cycle has finished, you may notice that you cannot move or speak.

Why the similar visions?

Although there are no facts available, there are scientific theories on why people with sleep paralysis see similar (sometimes exactly the same) visions. view the science theories page below.

Scientific theories