Have you ever experience a sudden jerk of the arms, legs or entire body that wakes you up? You feel like you are falling through space when are asleep. These involuntary movements are known as ‘ hypnic jerks’ or ‘sleep starts’. They also may be associated with flashes of light and loud noises and sensations such as falling, tingling or floating. However, these sensory experience can also occur without the body jerk.
Hypnic jerks are believed to be normal physiologic events. They are common and the exact cause is unknown. Some triggering factors are stress, caffeine, stimulant drugs and lack of sleep. They rarely require medical attention. Medical advice may be required if they keep you up all night.