Numbness of hands at night may be related to long time fixed posture, cervical spondylosis, sudden cerebral infarction and other reasons. 1. Prolonged fixed posture: Being in the same position for a long time during sleep and compressing one side of the arm may lead to blood circulation disorder in the hand, thus causing numbness of the hand. 2. Cervical spondylosis: When cervical spondylosis is serious, it may compress the cervical nerve root or cervical spinal cord during sleep, thus causing numbness of hands. 3. Sudden cerebral infarction: For middle-aged and elderly people with long-term hypertension, diabetes and smoking history, sudden numbness of unilateral limb or single limb during sleep may be numbness of hand caused by transient ischemic attack. Patients are advised to avoid sleeping on the side for a long time and go to the hospital if necessary to identify the cause and standardize the treatment.