What is Sleep Paralysis?

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By Dr Simon Kyle

Sleep paralysis comes in many forms each of which may be characterized by the inability to carry out normal body movements, voluntarily, in the period just before sleep onset or during the time taken to awaken fully. These periods of paralysis are often seen to co-occur with visual and auditory hallucinations or vivid, dream-like states which, whilst harmless, can be very frightening experiences. Although these hallucinations may be interpreted as dreams, they may also be mistaken for reality provoking a strongly fearful response.

Those who suffer from sleep paralysis commonly report feeling immense pressure on their chests during episodes, adding to their feelings of anxiety during the paralyzed state and can result in breathlessness. Unlike the rest of the body however, which remains paralyzed throughout, the ability to move the eyes may in fact be preserved. It is completely normal to experience sleep paralysis from time to time, however when it becomes frequent and distressing or is associated with other symptoms of sleep-wake disorder, then it may require treatment.

What causes sleep paralysis?
Sleep paralysis is closely related to a normal part of the sleep cycle know as 'REM atonia', a paralysis which occurs as part of normal 'rapid eye movement', or REM, sleep. Sleep paralysis may take place either as the body enters REM sleep or once leaving REM sleep but before the full REM cycle has taken place. Paralysis can be very brief, ending after a matter of seconds, but in other cases may stretch into several minutes.

Sleep paralysis may be associated with other sleep disorders, such as narcolepsy, or else be present in otherwise entirely healthy people. In cases where sleep paralysis is the only symptom experienced, a diagnosis of 'isolated sleep paralysis' (ISP) may be given.

Although not strictly 'causes' of sleep paralysis, there are several factors which are known to increase the chances of experiencing an episode of sleep paralysis. These include:

Sleeping in an upwards position on your back
Increased levels of stress or sudden lifestyle changes
Insufficient quantities of sleep
Alcohol consumption

Treating sleep paralysis
As sleep paralysis is more common in people who are sleep deprived, getting the right amount of sleep may be seen to reduce the number of episodes of sleep paralysis. Keeping a regular schedule and taking frequent exercise alongside reducing caffeine and nicotine intake may also prove helpful in lowering the likelihood of sleep paralysis occurring.

Filed under: Sleep disorders