Just before falling asleep, why does my body sometimes "jerk"?

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LessNes	ME TOO!!

Bill L	did you forget to finish your question ??

obscureb	Your body jerks because of a reduced blood flow to that limb. In effect, your brain is responding to the slowing of your heart rate, reduction in blood flow as if you were dying...it sends a signal to the nerve endings to spasm that limb, thus the quick twich.

o0o0o_xoxo_katie_xoxo_o0o0o	lol couldn't tell ya... that used to happen to my sister, so you're not the only one. Maybe you have twitchy muscles?

Cheryl W	Dont know why, but it happens to plenty of people.

Pippo p	soul is beginnng to fall out of phase with you body...but it jerks you back into alignment

kra_z_nic	that is called a hypnic jerk. there are a few theories as to why it happens.

poppy1	Hi, That happens to me too. I guess we are almost a sleep and our muscles start to relax and it causes us to jerk and it totally wakes us up from going to sleep all the way. At least that is my own opinion. poppy1

webboffin	It is caused by a nerve impulse cascade through the body. It commonly happens when in the state of relaxation. It is like all the nerve impulses in your body synchronise at once and gives you a little jump. Feels funny when it happens like an electric shock.

trippystemny	I don't have an answer for you, but I wanted to let you know you're not alone, I do the same thing. Sometimes I'm just beginning to dream and something happens like I trip, so I jump and wake myself up .. but sometimes my body just jerks for no apparant reason.

sleepingliv	These are signs of fatigue.

midnight_shinobi619	I do that too, I was wondering the same thing....

killfoot2001	It's called a hypnagogic jerk. I'm not sure why it happens. Here is a link to get you started though.

illuminati_sinner	Spasms

DJ	I don't know y it does that but probably you're trying to go to sleep but your body wants to be moving(I know because I am kinda psychic)

Goalie43	Spasms.

Tatum	that happens to me all the time!it feels so weird!

Michael E	It could be spasms if you are really tired. That happens to me but only when I have stayed up for a really long time and need sleep badly or if I didn't get enough sleep the night before. If you find yourself jumping up somewhat violently, it could also be related to Post Traumatic Stress disorder. Sometimes your sub-conscious slips into a bad memory and makes you jump out of the fight or flight response. I have worked with Psychologists who have suggested that I suffer from this and since working with them, I have noticed a big decrease in the number of times I jump (or bolt) out of trying to fall asleep.

rockysimon2005	you want to flex your mucles

E	Yeah. it feels like your body is suddenly falling, or being launched in a certain direction. It always scares the hell out of me! My fiance noticed it when that happened to me on time. He was like.. did you just have one of those "jerk" things? Apparently I thrashed when it happend.

That Other Guy	Those are just muscle spasms, its totally normal especially if youre sitting around for a while before you go to bed.

Spooky Ghost	That is called hypnagogic myoclonus and it happens to a lot of people. It is often accompanied by a sense of falling. There really isn't a clear reason for it happening, but I know that it often happens to me when I am falling asleep while trying to stay awake, like in the middle of class.

Skorge	cuz ur body is at rest and ur muscles are more liable to spams.

vtskigirl417	Because your muscles and nerves are relaxing. It's a very common thing.... just relax your body more before you go to sleep and it shouldn't happen as much!!

phantomlimb7	Why you are describing is called a myoclonic jerk. It's an involuntary muscle spasm just in the early stages of sleep. During sleep, your brain actually paralyzes the voluntary skeletal muscles of your body to some degree. This is supposedly some evolutionary protective mechanism when our ancestoral critters were dwelling in trees. Sometimes, on the edge of sleep, this hiccup in the system occurs resulting in a myoclonic jerk which wakes you up, and it's annoying. On the other hand, the opposite is much more horrible to contemplate. Some people experience a disorder called sleep paralysis, where they wake up, but the mechanism of their brain is faulty, so they cannot immediately resume voluntary control and they lay there, wide awake but unable to move or speak. Very scary!

Aslana	It's a sleep start or Myoclonic jerk. There are different therories on why it happens. Check out the link.

Melissa B	I believe it's because while your muscles begin to relax they contract.. thus making you jump.

Miranda Girl	This is just your muscles relaxing. Sometimes it will cause your legs or body to jerk or twitch when you get really relaxed;.

Zuker	My husbands always a jerk before bed, too. Oops, that's not what you said. I don't know the answer to that one.

Mike T	It's an innate response the brain makes. As you fall asleep there are a lot of changes that occur in the body. Metabolism and heart rate slow down for example. Your brain, being all powerful, observes these changes and suspects the body is dying or injured. So it causes this jerk to see if you're still alive. It's very uncommon to happen while you're awake (because everything is at the right level) but it can happen and is a symptom of some neurological disorders.

SnickerSnack	Twitches while falling asleep are called hypnagogic myoclonus, myoclonus being any sort of involuntary muscle spasm and hypnagogic referring to sleep. The twitches occur during very light sleep as the conscious brain gradually relinquishes control of the motor functions. Often they're accompanied by a sense of falling, or the feeling that something is flowing through the body, and sometimes people will experience vivid dreams or hallucinations. It's not known exactly what causes the twitches, but they appear to be associated (although by no means invariably) with (a) anxiety and (b) some faint stimulus, such as a noise. The twitches have been induced in test subjects who were instructed to push a button whenever they heard a low tone. When, as usually happened, the subjects nodded off after a while--you know how exciting psychology experiments are--the tone would often cause a subject to twitch after a lag of a few seconds. It's conjectured that the subjects consciously knew they were supposed to stay awake, that they fell asleep anyway, and that the tone jarred the semiconscious brain into trying to scramble itself into action again. That would explain why you experience the twitches during boring lectures. It's thought that at times the stimulus can be purely involuntary, such as a dream.