You know sometimes right after you fall asleep, you wake up in a startle, or a jerk... why do we do that?

Question

If anyone else actually does do that....

Answer 1

There's no certain explanation.
It's called a hypnic or hypnagogic jerk; this article will explain.

http://en.wikipedia.org/wiki/Hypnic_jerk

Here are three hypotheses listed in the article.

That it is a naturally occurring part of the sleep process, as is slower breathing, and reduced body temperature.

That the feelings associated with relaxation before sleep are misinterpreted by the brain as falling or toppling over, and by reflex the body jerks out the limbs to stay upright.

That in the same way a body will often twitch as a person dies (as a reflex to attempt to keep the body functioning) it is thought the body might misinterpret falling asleep as a situation in which the body needs to be stimulated.

Here's an external link from the same article.

That Strange Falling Sensation
http://www.failedsuccess.com/index.php?/weblog/comments/falling_sleep_hypnic_jerk

Answer 2

This is known as a "sleep start," is what doctors and scientists call a hypnic or myoclonic jerk, and it usually happens right before going into deeper stages of sleep.

Doctors think the myoclonic jerks happen. When you fall asleep, normally your body temperature goes down and your heart starts to beat just a little slower. This is because your brain signals your body to relax to prepare for sleep. When your muscles are relaxed, you go into the very first stages of sleep, but you're not sleeping too deeply yet.

This brain activity may cause your larger muscles to contract a little bit. In response, another part of your brain will make up a very quick mini-dream to go along with what is happening. You might think this would take a while, but your brain works so lightning fast that it makes up the story almost at the same instant that your muscles jerk. Myoclonic jerks are a normal part of sleep.

Answer 3

Some physiologists theorize that this is a purely physical phenomena. Even when you are asleep, your skeletal muscles still keep a certain amount of muscle tone (or tension). Every once in a while, for unknown reasons, your brain allows your body to relax even more than it usually does and (even in your sleep) it can leave you with the sensation of falling. The brain realizes that it has let the muscles relax too far and fires off a neural message to your muscles "HEY guys! Let's tighten things up a bit!"....and this is the "jerk" you feel that wakes you up.

Answer 4

I was once told that your spirit is leaving your body and floating around. The startle or jerk is when your spirit is falling back into your body. I am sure there is a medical/physical answer, but I like this one.

Answer 5

I used to wake up with a jerk every morning, but I divorced him.

-Seriously, I do that, once in a while. It's sure unpleasant, isn't it?

Answer 6

That's a myoclonic jerk or a hypnic jerk. There's info at http://www.goaskalice.columbia.edu/2291.html
http://en.wikipedia.org/wiki/Hypnic_jerk
http://www.failedsuccess.com/index.php?/weblog/comments/falling_sleep_hypnic_jerk

Answer 7

It happens to me when I have dreams of falling... It really sucks since I have broke my back... the sudden jerks are so painful somtimes....

Answer 8

This happens to alot of people and it is called Astral Projection. I don't know if you believe in things like that, but it is when you leave your body. And you feeling this jerk is when you enter into your body again. Maybe you should read up on it, or watch sylvia brown on the montell show on wednesdays on FOX. Or read some of her books. You will be surprised!!!!!

Answer 9

you may be dreaming that u r falling off of a cliff i do it alot when i am falling asleep it is pretty annoying and kinda scary when it happens

Answer 10

It's your nervous system relaxing and slowing down for sleep. Don't listen to these people saying it's astral projection.