The many familiar:
The eyelids are heavy, and it dawns slowly away – but then the twitches of the body, it discourages literally on.
This phenomenon is called “hypnic jerk” or “sleep start”, in English “sleep twitch” or “sleep onset”.
A total of 70 percent of all people have experienced this phenomenon already:
A brief Jerking of the limbs and the feeling of falling to.
But why is the man winces in the first place?
Dr. Carl Bazil from Columbia Sleep Disorders Center, has an explanation:
Most likely, our brain sends out different signals, so the two systems fight each other.
While this provides a System to ensure that the muscles relax so you can fall asleep, tried the other one awake.
“One thing that happens when you fall Asleep, our muscles relax. But the guard part is stimulated so, that he over-reacted for a short time and you wince, this contraction of the muscles has.” Dr. Bazil via New York Magazine
However, a bad sleep position, the sleep can twitching cause:
If the limbs hang over the bed and threaten to fall, the brain will Wake people up.
Experts say it could be a survival instinct.