Sleeping at night arm congestion, generally considered to be physiological reasons, cervical spondylosis, upper extremity venous thrombosis. 1. Physiological reasons: due to poor posture at night or sleep when the upper limbs are compressed, resulting in poor blood return to the upper limbs, arm congestion, through appropriate activities of the upper limbs, limb elevation of blood circulation, to improve the symptoms. 2. Cervical spondylosis: cervical spondylosis stimulates the sympathetic nerve to cause vascular regulation dysfunction, which may cause blood stagnation, and the symptoms may be alleviated by taking vasodilating drugs, such as dibazole and methylcobalamin. 3. Upper extremity venous thrombosis: blood flow may be blocked due to blood in a hypercoagulable state or blood clots caused by endothelial damage, which may result in arm congestion. There may also be other reasons for arm congestion at night, if the rest does not reduce, you need to go to the hospital for examination and targeted treatment.