You’re drifting off to sleep when suddenly you find yourself unable to move and unable to speak. But what’s causing that mounting sense of dread? Is it the shadowy presence you can see in the room, or the weight pressing down on your chest?
What is sleep paralysis?
Sleep paralysis is a parasomnia – an abnormal event during sleep. It’s seen during hypnagogia, the transition between waking and sleeping, when we can experience lucid dreaming, and hypnagogic jerks. It can also been seen, but less often during hypnopompia, the transitional state between sleeping and waking.
As we begin to enter REM sleep we automatically put our muscles into a frozen state called atonia. This is to prevent us from acting out our dreams. During sleep paralysis our muscles remain frozen as we move towards wakefulness. The result is that we can hallucinate, imagining a presence in the room, and find our breathing constricted, which we experience as a weight on our chest.
Because people remain unable to move or speak then at first they often find it very frightening. However, it normally lasts between just a few seconds or a few minutes before people wake fully. They can be anxious though about falling to sleep again.
How normal is sleep paralysis?
Around one in twelve of us will experience it, and the vast majority of those that do will only experience it once or twice. It is much less common than many other parasomnias such as hypnagogic jerks.
What causes sleep paralysis?
The exact cause isn’t understood, but it’s normally seen in people who
- are sleep deprived
- have irregular sleep patterns, including shift workers
- have sleep apnoea
- are on medication that affects REM sleep
Again, most of the people affected will only experience it once or twice in their lifetime.
How can I prevent sleep paralysis?
If you are prone to it then you need to look at your sleep habits and sleep hygiene.
- aim for eight hours sleep per night
- establish a regular sleep pattern
- avoid caffeine after midday, and exercise within four hours of going to bed
If after this you continue to have episodes of sleep-paralysis, or find them particularly disturbing or distressing, then your next step is to talk to your GP.
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