The reason why some patients experience cold arms during sleep may be due to the presence of localized cold arms, upper extremity vascular compression or peripheral neuropathy and other causes. 1. Localized coldness of the arm: such patients may have poor arm warmth during sleep, leading to local vasoconstriction. In addition, some patients have a weaker body, resulting in slower blood circulation. If the patient exposes his arm, it will become cold quickly. 2. Upper extremity vascular compression: these patients often have some bad sleeping posture, such as pressing the upper extremity under the pillow. This may lead to the blood vessels of the upper limbs being compressed, so that the local blood circulation is poor, and then the symptoms of cold skin. 3. Peripheral neuropathy: Some patients may feel the symptom of coldness in the upper limbs when they have some peripheral neuropathy, such as nerve root cervical spondylosis or upper limb nerve compression, but their skin temperature is not low. When the patient sleeps, the compression of the relevant nerves may be aggravated by poor sleeping posture, and thus the patient may feel localized coldness. It is recommended that patients should keep warm and apply warm compresses appropriately after experiencing the above symptoms, and if they cannot be relieved, they should go to the orthopedic department in time.