The muscles falling into a relaxed state and the body thinking its falling, is trying to signal the body for a response. Your muscles relax including your heart it gets so relaxed the body sends jerks to the heart so it doesnt relax so much that it doesnt beat.
That is a result of being over tired when you go to sleep.
2 years ago
Last edited at 12:14AM on 6/17/2011
The twitching is caused by muscles and if it occurs repeatedly, it could be a sign of a medical disorder. If the twitches are brief, it’s normal but if they are continuous it could be a problem, mostly a neurological one.