Sleep paralysis: definition, symptoms and causes

At the end of the 18th century, the painter Johan Heinrich Füssli finished one of his most emblematic works.

The painting, based on a painting by Giulio Romano, shows a sleeping woman who has a demon seated on his belly while the head of a horse appears between the fabrics that make up the background for the scene. It staged a fairly common sleep disorder: sleep paralysis.

What is sleep paralysis?

The dreamy and dark setting of this work called The nightmare makes the painting a perfect illustration of what could be one of the beasts of medieval European mythology: the incubus, a demon who is associated with the world of nightmares and who supposedly has relationships sex with women who, finding themselves between sleep and wakefulness, lie motionless without being able to nothing.

Today, some researchers believe that the mythology behind the figure of the incubus and his female alter ego, the succubus, is actually a supernatural interpretation of a Sleep disorder perfectly scientifically documented.

This disorder is calledsleep paralysis, and Füssli's painting expresses very well the sensations that are experienced while this curious phenomenon occurs.

What happen? Symptoms

The name of sleep paralysis is quite descriptive: is a sleep disorder in which the person is unable to perform any voluntary movement. This means that, for a short period of time, someone experiencing sleep paralysis will go through a state of consciousness. between sleep and wakefulness and will only be able to see what is happening around them, without being able to perform practically any action physical. You will be able to perceive what is happening around you where you have been resting, but you will not be able to move or ask for help.

Of course, sleep paralysis does not affect vital functions such as breathing and heartbeat, as these movements are involuntary. However, that does not mean that it is a very unpleasant and generating feeling anxiety, among other things because usually goes hand in hand with the feeling of not being able to breathe well (Not being able to control the vocal cords well, it seems that the air escapes from our lungs without being able to do anything to remedy it).

Thus, it is common to have the sensation of suffocation or to have difficulty breathing, but it is only of a consequence of not being able to consciously control the muscles, and there is no real risk of drown.

Sleep paralysis can occur with other factors of a subjective nature, such as hallucinations or the sensation of having strange or threatening presences nearby paralyzed.

This is mainly due to the fact that it appears in a transitional phase between sleep and wakefulness, and causes these hallucinations seem more real, occurring in places that we know and that belong at least partially to the real world in which we have been lately. For example, at first we can realize that we are in the bed in which we lay last night and therefore in the real world, the waking one, but then strange elements appear that are not possible in real life, such as levitated sheets, monsters, etc.

Frequent causes

Generally speaking, sleep paralysis is due to a lack of coordination between some areas of the brain and the part of the nervous system responsible for sending orders to the muscles that can be controlled voluntarily. This means that even though the person has regained consciousness and awakened, his muscles remain be "connected" to the brain, because they remain in the inert state that occurs during REM sleep, while we dream.

During the REM phase, the fact of having the muscles isolated from what happens in our consciousness is useful, because otherwise we would move our body based on everything that happens in our dreams.

However, this utility disappears in cases of sleep paralysis and the mechanism responsible for separating muscles and consciousness turns against us, since we experience what has to do with wakefulness and sleep: the hallucinations of the dreamlike, and the immobility of the physical world in which we really find ourselves sleeping.

Luckily this clears up in no time, usually after a few seconds. In any case, when this phenomenon appears in a state of transition between wakefulness and sleep, the perception of time could be somewhat altered.

In any case, the exact causes of this phenomenon are not entirely clear, and much remains to be investigated to understand its mechanisms.

Who can this happen to?

Different studies on the prevalence of sleep paralysis indicate that they are rare cases taking into account the number of times one person goes to sleep throughout their life, but the number of people who will experience this parasomnia at some point in their life could be controlling. Specifically, approximately 60% of the population could go through sleep paralysis.

However, the negative effects of sleep paralysis are found in the subjectivity and the sensations experienced by the person who experiences it, so having read something about this disorder could make this more bearable situation.

In any case, the fundamental thing is that although sleep paralysis is usually experienced in an unpleasant way, in situations It does not constitute a source of danger, nor does it lead to suffocation, despite the fact that sometimes the lack of control over one's own movements generates that fear of stopping breathing (a process automated by the nervous system itself and that does not depend on the actions volunteers).

Bibliographic references:

• American Sleep Disorders Association (1990). International Classification of Sleep Disorders: diagnostic and Coding Manual, In Press.
• Cheyne, J. (2003). "Sleep Paralysis and the Structure of Waking-Nightmare Hallucinations". Dreaming. 13 (3): 163–179.
• Jalal, B.; Simons-Rudolph, J.; Jalal, B.; Hinton, D. AND. (2014). "Explanations of sleep paralysis among Egyptian college students and the general population in Egypt and Denmark". Transcultural Psychiatry. 51 (2): 158–175.
• Teculescu, D.B.; Mauffret-Stephan, E., Gaultier, C.: Familial predisposition to snoring. (Letter) Thorax, 1994.