What causes sleep paralysis?

I think it has to do with waking up during the paralytic part of sleep. Or, having the stages overlap a little, and possibly REM being very short? Or, maybe the stage before it being very short? Since you wake, you become aware you are paralyzed. I would guess during REM is when the body is shut down from movement so we don’t act out our dreams. I believe it is somewhere near the base of the brain it functions to not deliver neurological messages to our body that the higher thinking brain has created in our minds.

I’m really not sure that is right, but that is kind of logically what makes sense to me. I bet nikipedia knows, I’ll send this to her.

Is there any chance you have sleep apnea, or very low heart rates and blood pressure at night?

If you’re concerned, check with your PCP.

“More formally, it is a transition state between wakefulness and rest characterized by complete muscle atonia (muscle weakness). It is thought to be a result of disrupted REM sleep which is normally characterized by complete muscle atonia that prevents individuals from acting out their dreams.

It can occur at sleep onset or upon awakening. Sleep paralysis has been linked to disorders such as narcolepsy, migraines, anxiety disorders, and obstructive sleep apnea; however, it can also occur in isolation.”
Source

Vitamin B12 deficiency commonly occurs only in people who no longer eat animal protein ( (eggs, meat, milk), So unless you are a vegan or vegetarian, that should not be an issue.

I’ve never experienced it but it is quite common. In folklore it is known as ‘old hag’ syndrome. The body naturally loses control of the muscles during deep sleep so we don’t act out our dreams.

About the B12, I know a lot of people who are low or low side of nornal in B12 levels. I am low side of normal without supplements, and several friends of mine. I have no idea if low B12 has anything to do with sleep paralysis, but I do think people should have their B12 checked periodically B12 does affect the neurological systems. Some ethnicities are prone to a dificiency that prevents the absorption of B12 from the stomach, but that is not extremely common.

It used to be a common occurrence for me when I was in my 20’s, particularly toward the end of sleep in late morning. I seem to have “outgrown” it with aging. It’s usually considered normal and not a cause for concern, though it can be quite distressing when it happens. It’s not well understood but seems to be (see @gailcalled‘s answer) an uncoupling of the sleep state with suppression of motor activity by the brain.

It is normal, scary, and harmless.

I’m also a sufferer of sleep paralysis. It can be freaky. I normally make weird noises too as on my mind I’m asking my wife to wake me up but it just comes out as weird groans apparently. I often see people in the room too.

@RareDenver, I have sleep paralysis. Do you know who is in the room or do you have a sense of whether the person in the room is going to do you harm?

@bkcunningham the people thing is not nice, it’s like they don’t know I’m there and often walk over me or stand on my chest.

I just wondered, @RareDenver. There is always someone shrouded in darkness in my bedroom watching me as I struggle to move and I try to scream. It is terrifying. Thank you.

Sleep paralysis occurs when you wake during your REM cycle. While you dream, your body paralyzes itself so that you do not act out your dreams and hurt yourself. It is more likely to occur when you sleep on your back, so definitely try to always sleep on your side. And yes, sleep paralysis can be accompanied by hallucinations. You should definitely speak with your PCP (primary care physician, not angel dust), who will probably refer you to a sleep specialist. When you are in the middle of sleep paralysis, I know it sounds stupid to say, but do try to remain calm. Good luck.