A toddler sweating a lot while sleeping may be caused by physiological factors, vitamin D deficiency rickets, tuberculosis and other factors. 1. Physiological factors: at night when you sleep, the indoor temperature is high or the bedding is too thick for the child, it will make the toddler sweat a lot when he sleeps, which is a normal physiological phenomenon. 2. Vitamin D deficiency rickets: children long time partiality and picky eating, resulting in the lack of calcium in the body too much, it will lead to children sweating more at night, may also be accompanied by sleep unsettled, crying and other abnormal manifestations. 3. Tuberculosis: usually associated with tuberculosis infection, the typical symptoms of night sweating, accompanied by low fever, fatigue and other symptoms. Young children sleep a lot of sweat, and accompanied by other abnormal performance, should be alert for disease factors, parents are advised to take their children to the doctor for examination and treatment.