The causes of numbness in the hands at night include diabetes, cervical spondylosis, and insufficient blood supply to the brain. 1. Diabetes: eating a lot of sugary food for a long time will raise blood sugar, which may cause diabetes in the long run, in which case the patient is likely to have weakness and numbness in the hands at night. 2. Cervical spondylosis: the patients of this disease in the sleep if the pillow is not suitable, or sleeping posture, resulting in neck muscle tension, spasm, resulting in local nerve root compression, resulting in dysfunction of the compressed nerves, may cause numbness of the hands, may also be accompanied by neck and shoulder discomfort, numbness of the upper limbs and other symptoms. 3. Insufficient cerebral blood supply: When there are abnormalities in the circulation of the brain, it will lead to abnormal blood flow and cause insufficient cerebral blood supply. At this time, the patient may also have numbness in the hands at night, which may be accompanied by memory loss and tinnitus and other symptoms. If the patient sleeps at night with numbness in the hands, it is recommended to consult a doctor in a timely manner, improve the examination and test, clarify the cause of the disease, and under the guidance of the doctor’s treatment.