Numbness of the arm sleeping may be caused by maintaining a posture for a long time, or it may be the manifestation of diseases, such as radiculopathy, elbow-tube syndrome, diabetic peripheral neuropathy, cerebrovascular lesions, polyneuritis, etc., should be promptly consulted to find out the cause of the disease. 1. Posture problem: If healthy people keep their arms in one position for a long time when they sleep, it may cause numbness for a short time due to long time pressure on blood vessels and local ischemia and hypoxia. 2. Neurogenic cervical spondylosis: due to degenerative changes in cervical intervertebral discs and intervertebral joints, the cervical nerve roots are involved, resulting in root compression or irritation, which can lead to symptoms such as radiating numbness and pain in the upper limbs, and also upper limb sensation of heaviness, neck and shoulder pain and other manifestations. 3. Elbow Canal Syndrome: the ulnar nerve is compressed by tendon membrane, abnormal muscle or bony changes in the elbow through the ulnar nerve groove, which causes pain in the elbow area, usually tingling or aching, which can be radiated to the proximal and distal ends, and there are symptoms such as numbness and hyperalgesia, which can lead to numbness in the arm when sleeping. 4. Diabetic peripheral neuropathy: peripheral neuropathy caused by diabetes mellitus with sensory and autonomic symptoms, patients can have abnormal sensation, muscle weakness, muscle atrophy and other manifestations, which can cause numbness in the arm while sleeping. In addition, arm sleep numbness may also be cerebrovascular lesions, polyneuritis and other diseases caused by repeated arm numbness, should go to a regular hospital, by the doctor to clarify the cause of the disease, give targeted treatment.