Sleep paralysis can be downright terrifying when experienced for the first time. Even when it occurs regularly, it can still be scary — especially when you don't fully understand what is going on.
_When we sleep, our brain tells our muscles to relax. During an episode of sleep paralysis, we wake but our brains haven't released the block on our muscles. As a result, it is difficult (or impossible) to move or even speak — yet we are fully conscious and aware of our surroundings. _
The scary symptoms of sleep paralysis
Sleep paralysis has been found to affect just under eight percent of the general population.
In addition to being awake but unable to move, common symptoms of sleep paralysis include:
- Visions, such as seeing a person or demon-like figure in the room
- Feeling unable to breathe, or being suffocated
- Hearing voices or other sounds
- Out of body experiences
An episode of sleep paralysis can last just a few seconds, or it can last for several minutes.
What causes these symptoms?
When we wake and are unable to move, the body's emergency response is activated. Being paralyzed makes us feel helpless, which heightens the body's response. This may explain why vivid visions and hallucinations are common.
Furthermore, the body will typically err on the side of caution when it faces a perceived threat. This could explain why we see figures and presences and interpret them as being evil.
It may even feel as though the figure or presence in the room is making it hard for you to breathe, or is even deliberately suffocating you. This sensation is again down to the body's response to a perceived threat, combined with the physiology of sleep.
Muscle paralysis removes voluntary control of breathing. When we wake in fear, our natural inclination is to breathe deeply to flood the body with oxygen to prepare for fight or flight. However, due to the effects of sleep paralysis, we are unable to do so. We may feel this as a resistance to our ability to breathe.
When combined with visionary hallucinations, this may explain why sleep paralysis can lead to the sensation of someone or something trying to suffocate us.
The out of body experiences some individuals report isn't down to the fight or flight response, though. One theory suggests that in cases of sleep paralysis, the processes which coordinate body position and movement become activated but because we can't move, the confusion creates a floating sensation.
What causes sleep paralysis?
Sleep lab studies have found that those who experience sleep paralysis:
- Enter REM sleep more quickly than normal
- Experience fragmented REM sleep
- Have shorter REM cycles
The authors of one study believe this suggests that the disturbance of regular sleep patterns can lead to sleep paralysis, as this is a common cause of fragmented REM sleep.
Another theory argues that problems with melatonin regulation may cause sleep paralysis. Melatonin regulates our sleep cycle and levels are usually at their lowest during REM sleep. If melatonin levels drop at a different stage of our sleep/wake cycle, it could lead to difficulty fully waking when the nervous system is stimulated and may explain why our muscles are paralyzed when we wake.
Because REM sleep fragmentation is highly heritable, sleep paralysis may even be genetic. Indeed, one study found that if one identical twin experiences sleep paralysis, the other twin is highly likely to experience it, too.
Finally, depression may be linked to sleep paralysis. One study found that 11 percent of those suffering from depression also experienced sleep paralysis. As the authors of that study note, this may be because depression can disrupt REM sleep.
How to treat sleep paralysis
You've already undertaken the first treatment — education! A better understanding of sleep cycles and knowing why you are unable to move when you wake can help.
You should also:
For serious cases, antidepressants or selective serotonin reuptake inhibitors may be prescribed.
If you experience sleep paralysis on a regular basis, you may want to speak with your doctor. He or she may evaluate you for narcolepsy, a sleep disorder that affects the sleep/wake cycle. Sleep paralysis is also more common in those suffering from sleep apnea.
Finally, it's worth bearing in mind that although sleep paralysis can be scary and even terrifying, it poses no immediate health risk.
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Martin is the creator of Insomnia Land’s free sleep training for insomnia. His online course uses CBT techniques to teach participants how to fall asleep and stay asleep. More than 4,000 insomniacs have completed his course and 97 percent of graduates say they would recommend it to a friend.