Is there a meaning to those dreams you have when you first fall asleep and you like fall or trip or slip and jerk back awake? Like barely any time has passed and the entire dream is just that quick fall that makes you jerk your whole body...do you know what I am talking about? Am I making sense? - Shelley, Chesapeake, VA
Oh yes; perfect sense! In fact, Ill bet every single person reading this has experienced exactly what you are talking about. Its called the Hypnic jerk. It happens when you are in the first stage of sleep, the Hypnagogic state, hence the name Hypnic jerk. During this state the body completely relaxes and muscle control begins to fall away causing a falling sensation, which is why we call it falling asleep. If you have too much on your mind or if you are having a fitful night of sleep and are not fully releasing your worries, you are far more likely to jolt awake from the experience because a part of you is alert enough to go into fight or flight mode and try to catch your fall, which results in the jerking action of the body.
Sometimes it will happen and you wont even wake from it. If you watch a baby fall asleep, youre likely to see it happen but the baby will rarely wake from it.
Little mini dreams sometimes come along with it. Even though you arent in REM at this point, the hypnagogic state will cause dream-like visions because it is an hallucinatory state. One of my facebook friends had dreamt that she slipped on a wet sidewalk when she jerked awake. I once dreamt I tripped over a wrinkle in the concrete floor of the grocery store! My brother in law once jerked so hard that he kicked the wall. He actually went to the hospital because he thought he had broken his foot! Its certainly nothing to worry about. Its just one of those quirky little side effects of sleep.