Men have also been known to experience this at a higher rate than women.
A higher occurrence is reported in people with irregular sleep schedules. It can also be accompanied by a vivid dream experience or hallucination. Hypnic jerks are associated with a rapid heartbeat, quickened breathing, sweat, and sometimes 'a peculiar sensory feeling of 'shock' or 'falling into the void''. Physically, hypnic jerks resemble the 'jump' experienced by a person when startled, sometimes accompanied by a falling sensation. Hypnic jerks are one form of involuntary muscle twitches called myoclonus. Random involuntary muscle contraction of unknown causation without pathology plus possibly associated with fatigue, sleep deprivation, caffeine, anxietyĪ hypnic jerk, hypnagogic jerk, sleep start, sleep twitch, myoclonic jerk, or night start is a brief and sudden involuntary contraction of the muscles of the body which occurs when a person is beginning to fall asleep, often causing the person to jump and awaken suddenly for a moment. Myoclonic jerk, hypnagogic jerk, sleep start, sleep twitch, night start
