Imagine this: You're fast asleep when all of a sudden you're awoken!
想像这个场景：正当你睡得很香的时候，突然惊醒了！
And not by your alarm clock.
而且你不是被闹钟吵醒的。
Your eyes open, and there's a demon sitting on your chest, pinning you down.
你睁开双眼，在你的胸前坐着一个恶魔，狠狠地压住你。
You try to open your mouth and scream, but no sound comes out.
你试图张嘴尖叫，但是无法发出声音。
You try to get up and run away, but you realize that you are completely immobilized.
你试图爬起来逃跑，但是你意识到你完全无法动弹。
The demon is trying to suffocate you, but you can't fight back.
那个恶魔试图让你窒息，但是你无力反抗。
You've awoken into your dream, and it's a nightmare.
你惊醒过来，原来这是一场噩梦。
It sounds like a Stephen King movie, but it's actually a medical condition called sleep paralysis,
虽然这听起来像一部斯蒂芬·金的电影，但是这其实是一种叫做睡眠瘫痪的身体状况，
and about half of the population has experienced this strange phenomenon at least once in their life.
大约一半的人在他们的一生中至少经历过一次这种奇怪的现象。
This panic-inducing episode of coming face-to-face with the creatures from your nightmares can last anywhere from seconds to minutes
这种与你恶梦里的怪物面对面的恐怖经历，可以维持几秒钟到几分钟，
and may involve visual or auditory hallucinations of an evil spirit or an out-of-body feeling like you're floating.
还有可能伴随对可怕事物的错觉与幻听，或者会产生一种灵魂出窍的感觉，比如你正飘浮在空中。
Some have even mistaken sleep paralysis for an encounter with a ghost or an alien abduction.
一些人错误地认为睡眠瘫痪是因为碰到了鬼或者是被外星生物绑架。
In 1867, Dr. Silas Weir Mitchell was the first medical professional to study sleep paralysis.
1867年，塞拉斯·威尔·米切尔医生成为第一个开展睡眠瘫痪研究的权威人士。
"The subject awakes to consciousness of his environment but is incapable of moving a muscle.
“研究对象对于周围环境意识清醒，但是他的肌肉无法动弹。
Lying to all appearance, still asleep.
表面上看，他似乎仍然处于睡眠状态。
He's really engaged for a struggle for movement, fraught with acute mental distress.
但是其实他一直在努力挣扎，试图移动，并且脑中充斥着严重的精神压力。
Could he but manage to stir, the spell would vanish instantly."
他只能够使劲试图移动，魔鬼的力量不久就会消失。”
Even though Dr. Mitchell was the first to observe patients in a state of sleep paralysis,
虽然米切尔医生是第一个观察处于睡眠瘫痪状态中的病人的人，
it's so common that nearly every culture throughout time has had some kind of paranormal explanation for it.
但几乎在各种文化的历史长河中都出现过对于这个现象超自然的解释。
In medieval Europe, you might think that an incubus, a sex-hungry demon in male form, visited you in the night.
在中世纪的欧洲，人们认为这是一个魔鬼，一个性饥渴的男性魔鬼在梦中造访他们。
In Scandinavia, the mare, a damned woman, is responsible for visiting sleepers and sitting on their rib cages.
在斯堪的纳维亚，是一头母马，一个噩梦般的女人，负责造访沉睡中的人们，并且坐在他们的胸廓上。
In Turkey, a jinn holds you down and tries to strangle you.
在土耳其，是一个神灵按住你，并且试图扼死你。
In Thailand, Phi Am bruises you while you sleep.
在泰国，是寡妇鬼使你在梦中受伤。
In the southern United States, the hag comes for you.
在美国南部，是女巫来造访。
In Mexico, you could blame subirse el muerto, the dead person, on you.
在墨西哥，可以归罪于苏布瑞丝奥·莫瑞克多，一个已经死了的人压在你身上。

In Greece, Mora sits upon your chest and tries to asphyxiate you.
在希腊，是莫拉坐在胸口上，试图使你窒息。
In Nepal, Khyaak the ghost resides under the staircase.
在尼泊尔，是住在楼梯下面的魔鬼凯安克。
It may be easier to blame sleep paralysis on evil spirits
也许把睡眠瘫痪这种现象归结于是因可怕的恶魔们而起更简单，
because what's actually happening in your brain is much harder to explain.
因为真正在人们脑海中发生的事情实在是太难解释了。
Modern scientists believe that sleep paralysis is caused by an abnormal overlap of the REM, rapid eye movement, and waking stages of sleep.
当代的科学家认为睡眠瘫痪是由于睡眠的REM阶段（快速动眼期）跟清醒阶段的非正常交错而引起的。
During a normal REM cycle, you're experiencing a number of sensory stimuli in the form of a dream,
在一个正常的快速动眼期中，会经历许多感官刺激，这些刺激以梦的形式加以表现，
and your brain is unconscious and fully asleep.
但是大脑是完全处于睡眠状态并且没有意识。
During your dream, special neurotransmitters are released, which paralyze almost all of your muscles.
在你的梦中，特殊的神经递质被释放，它们几乎麻痹了你所有的肌肉。
That's called REM atonia. It's what keeps you from running in your bed when you're being chased in your dreams.
这就叫做快速眼动期的肌肉迟缓。这也是为什么当你梦见在被追赶却不会真的从床上爬起来跑动的原因。
During an episode of sleep paralysis, you're experiencing normal components of REM.
在睡眠瘫痪这种情形中，你会经历快速动眼期的所有正常部分。
You're dreaming and your muscles are paralyzed, only your brain is conscious and wide awake.
你会做梦并且你的肌肉被麻痹，只有你的大脑非常清醒并且有意识。
This is what causes you to imagine that you're having an encounter with a menacing presence.
这就是让你产生遇到具有恐怖长相的人的幻觉的原因。
So this explains the hallucinations, but what about the feelings of panic,
所以，这解释了幻觉部分，但是恐慌部分怎么说呢？
strangling, choking, chest pressure that so many people describe?
扼死感，窒息感，胸部的压迫感，这些被很多人描述的感觉呢？
Well during REM, the function that keeps you from acting out your dreams, REM atonia,
事实是，在快速动眼期，使你睡觉时不会真正做出梦中行为的这种身体机能--快速动眼期的肌肉迟缓，
also removes voluntary control of your breathing.
也剥夺了你呼吸的自主控制权。
Your breath becomes more shallow and rapid.
你的呼吸变得更浅、更快。
You take in more carbon dioxide and experience a small blockage of your airway.
你呼入更多的二氧化碳，并且经历呼吸通道的微微堵塞。
During a sleep paralysis episode, a combination of your body's fear response to a perceived attack by an evil creature
在睡眠瘫痪这种情形中，你整个身体的恐惧反应聚集成为一种被邪恶生物攻击的感觉，
and your brain being wide awake while your body is in an REM sleep state triggers a response for you to take in more oxygen.
你的脑子十分清醒，当你处于快速动眼期的时候，会触发身体机制以呼入更多的氧气。
That makes you gasp for air, but you can't because REM atonia has removed control of your breath.
这就使你想要喘息以呼入空气，但是你不会，因为快速动眼期的肌肉麻痹已经剥夺了你控制呼吸的权利。
This struggle for air while your body sleeps creates a perceived sensation of pressure on the chest or suffocation.
这种当你睡着时身体为呼吸空气的挣扎，产生了一种可以被感知的感觉，这就是胸部压迫感或者说是胸闷的感觉。
While a few people experience sleep paralysis regularly and it may be linked to sleep disorders such as narcolepsy,
然而一小部分人会经常经历睡眠瘫痪，这也许与一些睡眠紊乱症有关，比如嗜睡症，
many who experience an episode of sleep paralysis do so infrequently, perhaps only once in a lifetime.
那些经历睡眠瘫痪的人很偶然也会产生嗜睡，也许一生中就一次。
So you can rest easy, knowing that an evil entity is not trying to haunt, possess, strangle, or suffocate you.
所以不用担心，因为你已经知道那些可怕的东西并不是在尝试缠上你、占有你、扼死你，或者使你窒息。
Save that for the horror films!
还是把这些想法都留给恐怖电影吧！