Imagine this:
You're fast asleep
when all of a sudden you're awoken!
And not by your alarm clock.
Your eyes open,
and there's a demon sitting on your chest,
pinning you down.
You try to open your mouth and scream,
but no sound comes out.
You try to get up and run away,
but you realize that you are completely immobilized.
The demon is trying to suffocate you,
but you can't fight back.
You've awoken into your dream,
and it's a nightmare.
It sounds like a Stephen King movie,
but it's actually a medical condition
called sleep paralysis,
and about half of the population
has experienced this strange phenomenon
at least once in their life.
This panic-inducing episode
of coming face-to-face with the creatures
from your nightmares
can last anywhere from seconds to minutes
and may involve visual or auditory hallucinations
of an evil spirit
or an out-of-body feeling like you're floating.
Some have even mistaken sleep paralysis
for an encounter with a ghost
or an alien abduction.
In 1867, Dr. Silas Weir Mitchell
was the first medical professional
to study sleep paralysis.
"The subject awakes to consciousness
of his environment
but is incapable of moving a muscle.
Lying to all appearance, still asleep.
He's really engaged for a struggle for movement,
fraught with acute mental distress.
Could he but manage to stir,
the spell would vanish instantly."
Even though Dr. Mitchell was the first
to observe patients in a state of sleep paralysis,
it's so common that nearly every culture
throughout time has had some kind
of paranormal explanation for it.
In medieval Europe, you might think that an incubus,
a sex-hungry demon in male form,
visited you in the night.
In Scandinavia, the mare,
a damned woman,
is responsible for visiting sleepers
and sitting on their rib cages.
In Turkey, a jinn holds you down
and tries to strangle you.
In Thailand, Phi Am bruises you while you sleep.
In the southern United States,
the hag comes for you.
In Mexico, you could blame
subirse el muerto, the dead person, on you.
In Greece, Mora sits upon your chest
and tries to asphyxiate you.
In Nepal, Khyaak the ghost
resides under the staircase.
It may be easier to blame
sleep paralysis on evil spirits
because what's actually happening in your brain
is much harder to explain.
Modern scientists believe that sleep paralysis
is caused by an abnormal overlap
of the REM, rapid eye movement,
and waking stages of sleep.
During a normal REM cycle,
you're experiencing a number of sensory stimuli
in the form of a dream,
and your brain is unconscious and fully asleep.
During your dream,
special neurotransmitters are released,
which paralyze almost all of your muscles.
That's called REM atonia.
It's what keeps you from running in your bed
when you're being chased in your dreams.
During an episode of sleep paralysis,
you're experiencing normal components of REM.
You're dreaming and your muscles are paralyzed,
only your brain is conscious and wide awake.
This is what causes you to imagine
that you're having an encounter
with a menacing presence.
So this explains the hallucinations,
but what about the feelings of panic,
strangling,
choking,
chest pressure
that so many people describe?
Well during REM,
the function that keeps you
from acting out your dreams,
REM atonia,
also removes voluntary control
of your breathing.
Your breath becomes more shallow
and rapid.
You take in more carbon dioxide
and experience a small blockage of your airway.
During a sleep paralysis episode,
a combination of your body's fear response
to a perceived attack by an evil creature
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.
That makes you gasp
for air,
but you can't
because REM atonia
has removed control of your breath.
This struggle for air while your body sleeps
creates a perceived sensation
of pressure on the chest
or suffocation.
While a few people experience
sleep paralysis regularly
and it may be linked to sleep disorders
such as narcolepsy,
many who experience an episode of sleep paralysis
do so infrequently,
perhaps only once in a lifetime.
So you can rest easy,
knowing that an evil entity is not trying
to haunt,
possess,
strangle,
or suffocate you.
Save that for the horror films!