The causes of sweating in the lower limbs during sleep include physiologic and disease factors. Physiological factors include environmental temperature, etc. Disease factors include autonomic dysfunction and infection. 1. Physiological factors: when sleeping outside temperature is too high may be manifested in sleeping lower limb sweating. Sweating of the lower limbs can also occur when the quilt cover is too thick during sleep. 2. Disease factors (1) Autonomic dysfunction: If the patient lives an irregular life, etc., leading to autonomic dysfunction, the symptoms of sweating in the lower limbs may occur. (2) Infection: If the patient catches a cold at night and has a fever, the patient may have symptoms of lower limb sweating. Excluding environmental factors, if the lower extremity sweating occurs for a long time while sleeping, it is recommended to go to the hospital in time.