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Sleep problems Supernatural

Sleep Paralysis: Medical Explanation

  • June 23, 2010
  • 5 min read
Sleep Paralysis: Medical Explanation

“I couldn’t move and I could continuously hear a disorienting buzzing sound in the room but I could not turn to look at it because I couldn’t move, I struggled, I couldn’t cry for help and I could sense a weight on my chest like someone was sitting on it. It was like being awake in a nightmare and I told no one because I thought that there was some kind of demon that came to menace me but people wouldn’t believe me.”

Khyaak - The Demon Of The Dark

One of the commonest experiences of sleep paralysis (once called Old Hag Syndrome) has been quoted above. In its simplest form, sleep paralysis is a condition in which people wake from sleep to find that they are unable to move. In Nepal, experiences similar to that of sleep paralysis are often reported and ascribed to covering of the body by Ghost of the dark “Khyaak” during sleep. Constantly reported about for thousands of years, different cultures at different parts of the world have different figures associated with such kind of experiences. What makes “sleep paralysis” interesting is the fact that it has been associated several uncanny phenomenon like alien abduction, angelic or demonic visitations. Now let us look at it from the perspective of Medical science to make it more interesting. I will not make in truth claims here and leave it for you, dear readers to decide if the explanation makes sense.


Medically, sleep paralysis is a common condition characterized by the inability to perform voluntary muscle movements occuring either during sleep onset (hypnagogic form) or upon awakening (hypnopompic form) and can often be accompanied by hallucinatory experiences. An attack of sleep paralysis is usually harmless and self-limited. It tends to be over in a minute or two as soon as the brain and body re-establish connections and the person is able to move again. It is most commonly associated with nacrolepsy, a neurological condition causing excessive uncontrollable sleepiness and sleep episodes occuring at anytime of the day. In the absence of nacrolepsy, sleep paralysis is termed as Isolated Sleep Paralysis (ISP) which occurs in otherwise healthy individuals and in some cases can be familial as well.

Classical symptom tetrad of Nacrolepsy:

  1. Excessive day time sleepiness
  2. Cataplectic attacks (sudden loss of muscle tone triggered by emotional stimuli like anger, fear, etc.)
  3. Sleep paralysis
  4. Hypnagogic and Hypnopompic hallucinations

Understanding normal sleep pattern:

The depth of sleep changes periodically. During sleep, your body alernates between orthodox or NREM (Non-Rapid Eye Movement) sleep and paradox or REM (Rapid Eye Movement) Sleep and the depth of sleep gradually increases with the beginning of NREM sleep. One cycle of NREM and REM sleep constitutes a sleep rhythm is repeated every 90 to 120 minutes and approximately 5 to 6 times within one night. NREM sleep occurs first and takes upto 75% of your overall sleep time. REM sleep is referred as paradoxical sleep because while the brain and other body systems becomes active (eye movement, accelerated respiratory and heart rate, rise in blood pressure, etc.), muscles become more relaxed. Dreaming usually occurs during each REM phase of sleep due to increased brain activity but only the last dream that took place before spontaneous awakening is remembered. Muslce atonia during dreaming state prevents our body from acting out your dreams.

Relation of REM Sleep with Sleep paralysis:

In a book “Speaking of Sleeping Problems” by Dietrich Langen, he explains about hypnagogic hallucinations:

Sensations occuring during sleep onset consist of optical or acoustic sensory experiences that are not the result of any external stimulus. They include flashes of light, colored rings, waves and other geometric figures, partly disfigured or fragmentary. Whole scenses with action sequences similar to visions also occur. Acoustic phenomenon include the perception of voices, hearing one’s name called or hearing entire fragments of conversation or music.

Sleep paralysis occurs in transition between wakefulness and sleep or vice-versa . The difference from normal REM sleep is that the REM atonia persists but waking consciousness is largely retained in sleep paralysis i.e. your brain is partially conscious and partially in dreamy state and often external environmental stimuli can be remembered. It may be either, a rational mind trying to make sense of dream sensations or a dreamy mind trying to percieve environmental stimuli but the hallucinations often turn horrific due to the fear that sets in due to paralysis.

Here is an Interview with Dr. Irshaad Ebrahim from London Sleep Center to asnwer your sleep paralysis related questions:

  1. What is sleep paralysis?
  2. Can sleep paralysis have long-term effects?
  3. Does sleep paralysis affect many people?
  4. At what stage of sleep does sleep paralysis occur?
  5. How can you treat sleep paralysis?
  6. What is happening to the brain during sleep paralysis?


  1. Demon like Khyaak, Succubus or Incubus sitting on a chest
  2. Out of Body Experience (OBE) expained by Astral projection or travelling (separation of soul from the body during sleep)
  3. Alien abduction

And in the end, few tips regarding prevention and treatment of sleep paralysis:

  1. Improve sleeping habits as it is frequently associated with chronic sleep deprivation, sleep disruptions and irregular sleeping schedule.
  2. Avoid stress and alcohol as they can lead to irregular sleep schedule and sleep disruptions.
  3. Sleeping by lying on sides as sleep paralysis is mostly experienced in supine position (lying on back).
  4. Medications for treatment of depression may be needed.
  5. Evaluation and treatment of nacrolepsy may be needed.
About Author

Sulabh Shrestha

Intern doctor and Medical Blogger Sulabh Shrestha


  • I have been experiencing frequent episodes of sleep paralysis for a long time. In fact, it occurred to me just last night after several months. Sometimes it’s accompanied by a buzzing sound or hallucination or like you mentioned, the presence of someone. I bumped into your article while I was trying to search what it actually is. I have been told about the “Khyaak” myth by my mother but didn’t know that it was related to sleeping disorder. I just came to know that they can be genetic. My mother and brother also experience such episodes at times. I hadn’t experienced it until they shared to me about their attacks. Is it possible that it could be a result of psychological effect or is it purely genetic? Sometimes I try to counter the attack by trying to open my eyes slowly and swiftly move my fingers in a pumping sort of action. And strangely, it works and I wake up! Sometimes it occurs again even after I fight back somehow. Are there any methods to counter or even avoid them without medication?

  • I believe this but khyaaks are real. I am an 18 years old boy and I have seem them many times. At first i thought I was dreaming but I kept on seeing them, I told my grandmother about this and what I saw was exactly what my grandmother and my Aunts had seen before.
    They don’t harm us, They are of different size and color, and they are very playful. They enjoy scaring people, pulling our bed sheets while we are asleep, tickling our feet, poking our head and so on but sometimes they go off limits.
    I am having these “SLEEP PARALYSIS” and I am very scared these days. I feel like every night they are watching me. I have already seen 3 of them. But nowadays whats scaring me are not among those three.

  • this happenes to me alot. it happened again last night just as i was about to fall asleep. i couldnt move and felt that something was trying to get in my body. i fight against it with everything i have and tried to reach out to my boyfriend who was beside me. my body feels like dead weight and i’m struggling inside of it. as soon as i open my eyes it goes away but happens again immediately when i close them. i reached for my boyfriend again and it felt like since it knew i was reaching for him it wanted to be in my body to get to him in a sexual way. was really freaking weird.

    • Mark my words, THIS IS VERY SERIOUS. You are being harassed by REAL DEMONS, these are fallen angels that rebelled against God with their leader LUCIFER, also known as SATAN. There is nothing on this earth to battle them, no tool, you cannot defeat them with words or with weapons of this world. You cannot defeat them with witchcraft, mediums, or psychs or spells THIS WILL ONLY MAKE IT WORSE, THIS WILL INVITE THEM INTO YOUR HOME!! When this happens to you in the future, if you want to make it stop IMMEDIATELY, you must cry out in the name of JESUS CHRIST, the son of the LIVING GOD. If you cannot speak then pray it WITH ALL YOUR MIGHT. Ask JESUS TO DELIVER YOU! Jesus has all power and all authority in heaven and on the earth and over all things UNDER THE EARTH meaning demons! It is by his name and through his authority ONLY can you combat them.

      Please heed these words, God be with you!

  • I hv also experienced similar events,an evil stood by my bed every night,grabbed me,pulled my legs and i could not move or breath,i tried to call my room mate sleeping in d same room but no voice..it happend continuously for 2 weeks..i became severely ill out of fear,lack of sleep..at last my fiancé consulted a psychiatrist,i was given clonazepam and escitalopram and had a few counsellings done…i am completely alright now.it was all out of excessive stress.

  • I have had this happen to me often especially since I’m pregnant I’ve heard many things like my fiance is mexican and his family tells me theirs a demon trying to take a pure soul or something like that. But I don’t think that I think its a succubus because I get turned on when it happens to me. How I describe it is I feel like theirs something or someone in the room and then all off a sudden I can’t move but I can control my breathing it feels evil but like.. I’m not sure how to explain it like a sex evil its really strange

  • i am so happy to find this site..I have suffered with this paralysis as I fall asleep for months…last night it came over and over again, every time I started to doze off…the terrorizing paralysis and attacks…the screaming in my ears, the pushing on my chest, my head, my face…the evil I feel…it’s horrible. And worse,, i am aware and completly unable to move a single muscle, not an eyelash. My dog lays next to me sleeping, unaware of the horrific attack that is taking place to his master..I change postion,change to another room, another bed, no help..once I have an attack …more will follow …all night they torment me, just at the moment of falling…

  • Hi
    I’m new to this and have just started doing some reserch into sp.I had another episode last nite,it felt as tho the air became thick and I couldn’t move or cry out.I heard a voice say to me if you open your eyes you will see me.but I didn’t as I was afraid of what I may see.I felt a presence in the room and as soon as it went I could move again.any feed back would be gratefully recieved.
    Many thanks.

    • Sarah, Thanks for sharing your experience,
      Medically as I said, its a physiological phenomenon,
      and rarely a condition called Isolated sleep paralysis, Hope the article answers your curosity.

  • i can’t wait for taylor lautner’s new movie abduction to come out…he’s so awesome!

  • An excellent review that respects both the medical model and the cultural diversity of the phenomenon! thanks. As a sleep paralysis educator, I help people who have isolated SP (no narcolepsy or other sleep disorders), specifically by working with their fear. When SP/HH is encountered with an open heart and curious mind, negative apparitions can transform into helpful “entities” including angel visitations, ancestral encounters, and even sexual experiences.

    I had never heard of the Nepalese tradition before — is there any reading material about this (in English)?

    • How can you make an encounter from these, “entities” into something good? By ENCOURAGING THEM? How can angel visitations be just two commas away from sexual experiences? The Pure, and Holy leaders of the LORD, the leaders of his holy army would NEVER associate themselves with sinful sexual acts. If these entities were those of angels they would not devote themselves to these tactics to make you afraid or paralyze you and force themselves upon you. And as for ancestral encounters, the truth is, there is one life, and THEN THE JUDGMENT. After a human being dies, their soul does not stick around, they either go to heaven or hell. Demons HOWEVER, can imitate someones ancestors. In conclusion, these encounters are NOT GOOD. And SHOULD NOT BE ENCOURAGED. These encounters are demonic in nature, they only intend to strike fear and doubt into the hearts of those they oppress. If you want to help people with their sleep paralysis, teach them about JESUS CHRIST, and his kingdom, HE is the only one that deliver the oppressed. Outside of him, contact with the spiritual realm is forbidden for our own safety, trying to contact so called “helpful entities” that are not of GOD will only bring about the destruction of your soul.

      • Are you ok? Just wondering I suffer from SP. I have never thought it to be a demon nor a helpful entity. Mine are pure evil MEN/WOMEN trying to trick my family into trusting them and I can’t save them. Or maybe a predator, sometimes who wants to watch me die. But mostly harming my family. Why does it have to be a demon or an angel why can’t it just be a man?

    • sleep paralysis educator? i m a student trying to research on sleep paralysis.would you mind helping mme?

  • Both concepts explained, Great article.

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