What Is Sleep Paralysis and Why It’s So Dreadful?

written by / July 19, 2019
What Is Sleep Paralysis - Featured

Have you ever dreamed someone is chasing you and you can’t escape, scream, or get help? Or you can open your eyes but can’t move your body? If yes, then you’ve experienced sleep paralysis. This unpleasant condition is one of the most terrifying night-time experiences someone can have, but there are ways to treat it—even prevent it. 

What Is Sleep Paralysis?

During sleep, normal muscle relaxation occurs in the human body, known as muscular atony. In sleep paralysis, however, this muscle condition seems to continue even when the mind is already awake.

According to the experts, this produces a sleep-related paralysis that can occur in healthy people, but it may also be associated with narcolepsy, cataplexy, or hallucinations. The pathophysiology of this condition is closely related to the normal hypotension that occurs during the REM stage of sleep

The incidence of these episodes tends to vary. It may only occur once in a lifetime, but it can also happen several times a year, a month, even weekly. Typically, the episode lasts from a few seconds to a few minutes, and it resolves on its own. However, if you’re worried about how to stop sleep paralysis, keep in mind that physical contact or even just outside noises can help terminate this state.

The episode of temporary immobility may also be accompanied by the appearance of hallucinations—visual, auditory, or olfactory. It’s not uncommon for these to include the feeling of someone else’s interference, especially if it’s of a threatening nature.

What Is the Definition of Sleep Paralysis?

During a sleep paralysis episode, there’s full awareness of what’s happening when a sleeper is in this state. In fact, in most cases, we realize we’re dreaming, but at the same time, we can’t wake up. A sleeper is temporarily unable to speak or move their body or head, which is why they experience such intense fear. While you may feel like you can’t escape the dream, it’s really just hallucinations. Your brain makes you subconsciously believe they’re happening.

Initially, when people tried to explain sleep paralysis, a demon was believed to be the cause, particularly one that would sit on the sleeper’s chest. The original definition of sleep paralysis was given by Dr. Samuel Johnson in his English dictionary as a “nightmare,” a term that has since evolved into the modern definition. The Nightmare, by Henry Fuseli (1781), is believed to be a classical painting representing sleep paralysis in the form of a demonic visit.

The most common sleep paralysis stories create connections with spirits, demons, or alien abductions. What’s more, they have a long history. The Old English name of these beings was either mare or mære (from the proto-German word marōn). Some researchers suppose that the word is etymologically related to Maron (from the Odyssey) and Sanskrit’s Mara (Māra-demon). 

The Epidemiology of Sleep Paralysis in a Dream 

Sleep paralysis most commonly occurs in the second and third decades of life, although it may persist at a later age. The first episode often happens in the teen years, between 14 and 17. Sleep paralysis is a widespread phenomenon affecting almost four out of ten people worldwide. It’s more common in children and adolescents and can affect both men and women.

In studies from Canada, China, England, Japan, and Nigeria, up to 60% of people have reported experiencing sleep paralysis at least once in their lives. Another study revealed a prevalence of sleep paralysis among Iranian medical students. Around 24.1% of students have experienced sleep paralysis at least once in their lives. Similar results have also been reported among Japanese, Nigerian, Kuwaiti, and US students.

Why Does Sleep Paralysis Happen?

What Is Sleep Paralysis - Epidemiology

Physiologically, sleep paralysis is related to atonia during the REM phase of sleep. Sleep paralysis occurs either as we fall asleep or as we wake up. When it happens as we fall asleep, the person remains conscious while the body stops working and moves into REM sleep, this is called the hypnagogic or predormital form. When it happens as we wake up, the person becomes aware before the REM cycle is completed. This is called hypnopompic, or postdormital sleep paralysis. 

However, it’s the duration that gives people a good reason to develop a fear of sleep paralysis. While paralysis usually lasts from a few seconds to a few minutes, in some rare cases it lasts for hours.

Interestingly, during the REM phase, paralysis is not entirely complete. It was seen that eye movement is possible during episodes of sleep paralysis. If the patient doesn’t also have narcolepsy, then sleep paralysis is considered an isolated concern.

What Is the Cause of Sleep Paralysis?

Episodes of sleep paralysis are associated with the following conditions:

  • Other sleep disorders—like chronic insomnia, shift work, narcolepsy, muscle cramps during sleep, etc.
  • Mental illnesses—particularly among patients suffering from depression, panic disorder, post-traumatic stress disorder, and bipolar affective disorder
  • The use of certain medications
  • Drug abuse
  • Migraines

Some reports claim that various factors increase the likelihood of paralysis and related hallucinations. Therefore, the following could be considered additional sleep paralysis causes:

  • Insufficient sleep
  • Sleeping on one’s back
  • Increased stress
  • Sudden environmental changes
  • Changes in one’s daily routine or lifestyle
  • The excessive consumption of alcohol combined with a lack of enough sleep 

Certain sleep positions, like sleeping on your back with your arms crossed over your chest, contribute to the occurrence of sleep paralysis. This posture compresses the body. During sleep, the brain may then translate this physical discomfort into a nightmare.

How to Recognize Sleep Paralysis Symptoms

The condition is hard to recognize, but it’s usually accompanied by these symptoms:

  • An inability to move parts of the body—usually, this is the most stressful symptom
  • Chest compression and difficulty breathing
  • Complete awareness of what’s happening during sleep
  • A clear perception of one’s environment and surroundings
  • The inability to overcome an episode’s fear and horror

Diagnosis is based on personal history, and in some cases, it requires a polysomnography study. If you experience any sleep paralysis hallucinations or other symptoms, it’s best to visit a doctor because stress may provoke it. The most commonly reported hallucinations include doors opening, animals growling, the sound of footsteps, scratching, murderous whispers, the smell of rotting flesh, and a sense of death. 

We’ve already discussed the perception of a sleep paralysis demon. For many patients, this foreign, “evil” presence can be seen or felt. Meanwhile, the sleeper may experience unusual visual, olfactory, or auditory sensations. Patients may have a sense of movement or even experience hot, cold, or wet sensations. Some have even reported out-of-body experiences. 

We’ll cover treatment next, but know that it’s essential to try to sleep eight hours a night. You can find additional information about the benefits of healthy sleep here. Typically, the first step is discovering what’s causing the frequent occurrence of your sleep paralysis, so that you can take steps to remove it from your lifestyle.

What Is the Best Sleep Paralysis Treatment?

What Is Sleep Paralysis - Symptoms

There’s no specific treatment for the condition. Instead, treatment aims to control the underlying cause, depending on the individual case. It usually begins with studying the patient’s sleep stages and their muscle atony, which is often associated with REM sleep. If the symptoms persist, patients should consider getting tested for narcolepsy.

Usually, doctors will advise patients to improve their sleep habits and keep a bedtime routine. In more severe cases, patients may be prescribed a low dose of antidepressants, which can help reduce the number of episodes and alleviate the symptoms by suppressing some of REM sleep’s more problematic characteristics.

How to Prevent Sleep Paralysis

It’s often difficult to prevent sleep paralysis episodes in susceptible individuals. Sleeping for excessively short or long periods (i.e. less than six hours or more than nine hours) can further hinder its prevention, as can taking naps that last more than two hours.

However, there are some tips that could help patients:

  • Avoid falling asleep on your back.
  • Do what you can to avoid repeatedly waking up during the night.
  • Reduce any alcohol or cigarette use. The consumption of coffee, surprisingly, has not been associated with sleep paralysis.
  • Practice meditation and muscle relaxation techniques.
  • Try to move your fingers or toes during an episode to terminate it sooner.
  • If you have anxiety, consider cognitive behavioral therapy.


Is sleep paralysis dangerous?

Despite its startling nature, sleep paralysis isn’t a serious medical condition. However, some consideration should be given to the psychological concerns that may be causing it.

Why does sleep paralysis occur?

In each stage of sleep, the body behaves differently. During the REM phase, you become unable to move your body because your muscles fully relax. Meanwhile, REM is supposed to immerse the subconscious in sleep. However, during sleep paralysis, the body still remains motionless, but the brain is alert. This happens especially when we are having nightmares.

Can sleep paralysis kill you?

Although it may feel like you’re going to die during a sleep paralysis episode, this is actually impossible. There’s no credible evidence that this condition has ever been a cause of death. While there are other sleep-related deaths, none are proven to be connected to sleep paralysis. The occurrence of death during sleep paralysis would be related to another illness, not sleep paralysis itself. Even while theoretically possible, it would be challenging to find a relationship between sleep paralysis and death

Why is sleep paralysis so scary?

Sleep paralysis’s primary symptoms include the inability to move while also feeling like your breathing has shortened. With this, the disorder may be accompanied by terrible hallucinations and a great sense of danger. 

Sleep paralysis is especially frightening because these hallucinations are sometimes incredibly vivid. Luckily, patients can sometimes interpret the experience as a dream rather than a real event.

How can sleep paralysis be prevented?

We may not know precisely how to stop sleep paralysis forever. However, treating underlying disorders—such as narcolepsy, anxiety, or insomnia—should be the best way to prevent it. Other ways to manage the condition include improving your sleep habits, taking antidepressant drugs, and treating any mental health problems or other sleep disorders. The aim is to regulate your sleep cycle and avoid any triggers that may contribute to sleep paralysis.


The severe pain of being unable to move, talk, or react both subconsciously and in a dream can be terrifying. However, these symptoms should be much easier to accept now that we have an answer to the question, What is sleep paralysis? We know that during sleep, a person doesn’t lie motionless all night, and if we manage to stay calm during the episodes, we can cope with the experience. What’s more, when we identify what underlying causes induce our sleep paralysis, there’s hope that we can also prevent it in the future.

At medical school, it was easy to realize that sleep is crucial while studying during the many sleepless nights I spent. As a new mom, when the lack of sleep became even more evident, this was the real moment when I started appreciating the benefits of a good night’s sleep. Since sleeping is so essential to our health and immune system, I took it upon myself to educate people on different aspects of sleep by sharing the valuable information I have learned.