Half of the body suddenly numb after a while to consider and physiological factors, transient ischemic attack, mental factors and so on. 1. Physiological factors: when the patient takes the lying position, if the posture is not correctly compressed half of the body, there will be a sudden numbness, usually after lifting the compression, it will be improved by itself. 2. Transient ischemic attack: at the onset of the disease, the patient will suddenly have half of the body suddenly numb symptoms, generally short-lived, within an hour will return to normal, generally do not leave a neurological sequelae. 3. Mental factors: patients with depression can be conscious of half of the body suddenly numb, belonging to no organic lesions caused by psychological factors. Half of the body suddenly numb after a while may also be caused by other reasons, should go to the hospital timely consultation and treatment, clear reasons for targeted treatment.