A 5-year-old child who sleeps at night sweats a lot, may be sleeping environment temperature is too high, lack of vitamin D and calcium, hyperthyroidism and other reasons. 1. Sleeping environment temperature is too high: children sleep at night when the bedroom air circulation is poor, high temperature, bedding or pajamas are too thick and other factors lead to an increase in body surface temperature, the body through a lot of sweating and heat dissipation, is a physiological phenomenon. 2. lack of vitamin D and calcium: long-term malnutrition or lack of light children are prone to lack of vitamin D and calcium, calcium ion levels are too low leading to increased nerve excitability, irritability, muscle contraction spasms and other symptoms during sleep and good sweating. 3. Hyperthyroidism: children with hyperthyroidism synthesize and secrete a lot of thyroid hormones, resulting in increased body metabolism, increased heat production, and thus will sleep a lot of sweating at night to dissipate heat. The 5-year-old child sleeps a lot of sweat at night, there may be other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.