Sleep Paralysis: What Is It, Why Does It Happen and Is It Dangerous?
You have woken up but cannot move. Your body feels frozen, breathing is heavy, and sometimes it seems as though there is something in the room. A few seconds or minutes — and it all passes. If you have experienced this, you know it is one of the strangest and most terrifying sensations that can occur during sleep. This is sleep paralysis — and it is far more common than you think.
What Is Sleep Paralysis?
Sleep paralysis is a condition in which, while waking up (or falling asleep), you are temporarily unable to move or speak, even though you are fully conscious. It lasts from a few seconds to a few minutes and passes on its own.
Medically, it is not a disease — it is a physiological phenomenon related to the overlapping of sleep phases. It can happen to anyone, at any age.
Why Does It Happen?
To understand sleep paralysis, it helps to briefly understand what happens during sleep.
During the REM sleep phase (rapid eye movement phase), the brain is highly active — this is when we experience our most vivid dreams. To prevent us from acting out our dreams and physically injuring ourselves, the body is naturally paralysed during this phase — the muscles are temporarily relaxed.
Sleep paralysis occurs when consciousness has already woken up, but the body has not yet exited the paralysed state of the REM phase. In other words — the brain is already "switched on", but the body is still "switched off".
Why Does It Happen More Often to Some People?
Sleep paralysis is not a random phenomenon. There are several clear reasons why it recurs:
Sleep deprivation and an irregular sleep routine
This is the most common reason. When we sleep too little or at varying times, sleep cycles are disrupted and the REM phase can "intrude" into the moment of waking. People who sleep significantly longer at weekends than during the week experience this particularly often.
Stress and anxiety
A high level of stress directly affects sleep quality and the structure of sleep phases. Anxiety can destabilise the REM phase and increase the likelihood of sleep paralysis.
Sleeping on your back
Research shows that sleep paralysis occurs significantly more often in people who sleep on their back. Why this is the case is not fully understood, but it is thought that this position alters the breathing pattern during the REM phase.
Irregular sleep schedules
Shift work, frequent travel across different time zones, late nights — all of this destabilises the internal biological clock and increases the risk.
Genetics
Some people simply experience it more often — regardless of lifestyle. Research suggests that sleep paralysis may be hereditary.
Why Is Sleep Paralysis So Frightening?
The paralysis itself — the inability to move — is already unpleasant. But many people report something more: visual or auditory hallucinations, a feeling of pressure on the chest, a sense that something foreign is in the room.
This is not fantasy — it is neurologically explainable. During the REM phase, the brain generates dream images. When consciousness is awake but REM is still continuing, these images "transfer" into the real environment — as though the dream is spilling into reality. This is why people see shadows, feel a presence, hear sounds.
In different cultures this phenomenon is explained differently — Lithuanians spoke of a "pressing old man", the English of "witch riding" (a witch on the chest), the Japanese — "kanashibari". All of these are one and the same phenomenon, just under different names.
Is Sleep Paralysis Dangerous?
No. Although the experience can be very frightening, sleep paralysis itself is not dangerous to health. It passes on its own and leaves no physical consequences.
However, there are some situations where it is worth consulting a doctor:
- If sleep paralysis recurs very frequently (several times a week)
- If strong daytime sleepiness appears simultaneously without a clear reason
- If it is accompanied by intense hallucinations or panic attacks
- If it interferes with daily life
In such cases, a doctor can assess whether there are related sleep disorders, such as narcolepsy — a condition for which sleep paralysis is sometimes a symptom.
What to Do During Sleep Paralysis?
The hardest part — not to fight it. The instinct is to move as quickly as possible, but efforts can prolong the episode. Here is what helps:
Breathe slowly. This is the only thing you can control. Deep, calm breathing helps you exit the REM paralysis more quickly.
Do not try to move your whole body at once. Instead, try to move just a finger or your eyelids — even a small movement can "break" the paralysis.
Remind yourself what is happening. "This is sleep paralysis. It will pass. I am safe." A conscious thought reduces fear and helps you exit the state more quickly.
Do not try to fall asleep again immediately. If you lie down in the same position and immediately try to fall asleep, the paralysis may recur.
How to Reduce the Frequency of Sleep Paralysis?
Good news — this depends greatly on sleep hygiene, which can be improved:
Sleep at the same time. A regular sleep routine stabilises the biological clock and reduces the likelihood of disruptions in the REM phase.
Sleep enough. Adults need 7–9 hours. Sleep deprivation is the main cause of sleep paralysis.
Avoid sleeping on your back. If you have noticed that paralysis most often occurs when sleeping on your back — try sleeping on your side. A suitable pillow that holds the side-lying position helps with this.
Reduce stress before sleep. The phone screen, news, intense conversations before bed — all of this activates the nervous system and destabilises sleep phases.
Take care of your sleep environment. Darkness, quiet, coolness and comfortable bedding — this is not a luxury but the conditions that allow the body to pass through sleep phases without disruption. If the bedroom is too warm or the bedding does not allow the body to relax, sleep cycles are disrupted — and this directly increases the risk of sleep paralysis. Breathable fabrics such as percale or tencel bedding help the body maintain an optimal temperature during the night and do not disturb the REM phase.
In Summary
Sleep paralysis — frightening, but not dangerous. It is a moment of desynchronisation between the body and consciousness, experienced regularly by around 8% of people and by even more — at least once in their lifetime.
The best protection — good sleep hygiene: a regular schedule, sufficient duration, a suitable environment. A body that passes through sleep cycles properly rarely gets "stuck" between phases.
And if it does happen — know that you are safe, it passes, and millions of people around the world know exactly the same feeling.