The causes of hand numbness in sleep include physiological causes, cervical spondylosis, carpal tunnel syndrome and so on. 1. Physiological reasons: If you lift heavy objects during the day, use your hands excessively, or sleep in an improper posture, compression to the fingers, there will be hand numbness. After resting and relieving the pressure, it will get better. 2. Cervical spondylosis: with cervical spondylosis, easy to compress the cervical nerve root when sleeping, there will be symptoms of hand numbness, in addition to hand numbness, neck and shoulder, neck, shoulder and back and head, upper limbs, etc. will have pain and numbness. 3. Carpal tunnel syndrome: due to strain, external forces, etc., resulting in ligament thickening, carpal tunnel stenosis, patients with numbness or tingling in the radial side of the three fingers, exacerbated at night, the pain is aggravated by high temperatures, and there will be insensitive finger movement. It is recommended that patients who have numbness in their hands during sleep and do not get relief for a long time should consult a doctor in time, complete the relevant examinations, and target treatment after clarifying the cause.