When you are falling asleep and your body suddenly jerks, jolts or startles, this is a hypnic jerk or benign myoclonic jerk. Some people refer to them as a twitch, start or involuntary contraction, but all words are describing the same activity.
As it is thought that up to 60% of people experience hypnic jerks, it is listed in the International Classification of Sleep Disorders, but sleep experts agree hypnic jerks are not cause for worry. This involuntary muscle movement often happens when the body is between asleep and awake. It is generally accepted knowledge that a hypnic jerk is a body’s way of signaling sleep deprivation and that a good night’s sleep is much needed.