Jerks during Sleep
Jerks during Sleep (Myclonic Jerk)(dreams)
Falling dreams typically occur at the beginning of the night, in Stage I sleep. Such dreams are often accompanied by muscle spasms of the arms, legs, or the whole body that seem to happen just as one hits the ground in the dream. These sudden contractions—the technical name is myclonic jerk—are common in many mammals. Sleep researchers have paralleled them to the reflexive actions we experience as hiccups. There has been much speculation as to their cause, but the precise explanation remains unknown. One hypothesis is that it is part of an arousal mechanism. The thought is that this allows the sleeper to awaken quickly in response to possible environmental threats. One of the more common occurrences of the myclonic jerk is when dreamers experience falling dreams and their muscles contract just as they hit the ground.