The numbness of the hand when sleeping may be caused by local compression due to: 1. Cervical spondylosis appears to be a blood lipid abnormality, peripheral neuritis can also cause similar symptoms, incorrect sleeping posture can lead to long-term local compression, affecting the normal blood circulation, which leads to numbness in the hand. The degenerative changes in the cervical spine after the appearance of cervical spondylosis and the protrusion of the intervertebral disc can compress the vertebral artery or adjacent nerve roots, resulting in local sensory abnormalities in the nerve root control of the corresponding segment, leading to hand numbness. 2. Hyperlipidemia can affect the safety of the tiny blood vessels in the body, leading to microthrombosis, which can also cause peripheral circulation disorders, leading to hand numbness. 3. Peripheral neuritis can affect the normal function of the nerves due to local inflammation. The reaction affects the normal function of the nerves, thus causing abnormal local sensation.