Numbness of arms and hands at night is usually caused by localized pressure, or cervical spine lesions, strokes and so on. 1. Localized pressure: when you sleep at night and press your arm, if the time is longer, it is easy to make the local blood circulation obstacles, thus appearing arm numbness, hand numbness. 2. Cervical spine lesions: when suffering from cervical disc herniation and other diseases, the lesion of the cervical spine is easy to compress the nerve root, thus causing numbness of the arms and hands. 3. Stroke: it can develop at night, so there can be symptoms of arm and hand numbness while sleeping, and it can also be accompanied by limb weakness, dysarthria and other symptoms. In addition to the above factors, we can not rule out the possibility of other causes, it is recommended that when the symptoms persist, go to the hospital in time for examination and treatment.