The main reasons for sudden jerking in sleep include physiologic factors and disease factors such as epilepsy and calcium deficiency. 1. Physiological factors (1) At night, when the outside temperature is cooler, the symptoms of sleep jerking can be manifested when the body gets cold. (2) When the patient is overworked during the day, he or she may have a sudden jerk during sleep. 2. Disease factors (1) Epilepsy: The symptoms of sudden jerking in sleep occur at night due to the discharge of neurons in the brain, which is diagnosed by combining with cranial MRI and EEG. (2) Calcium deficiency: muscle spasms occur when the body lacks calcium, and sudden jerking can occur during sleep. Frequent episodes of sudden jerking in sleep can not be ruled out and disease-related, it is recommended to go to the hospital in a timely manner, under the guidance of the physician, to identify the causes and then give targeted treatment.