One and a half year old babies sleep sweating physiological causes is normal, pathological causes is not normal. Sweating may be caused by too much heat, vitamin D deficiency, hypoglycemia and so on. 1. too hot: the indoor environment is too hot or too thick clothing, due to the baby’s metabolism, the central nervous system thermoregulation center is immature. Children are prone to sweating when they fall asleep. 2. Vitamin D deficiency: rickets caused by vitamin D deficiency, in addition to night sweating, there are night terrors, hair thinning, occipital baldness, square skull, rib ectropion and other symptoms, need to be given vitamin D supplementation, and appropriate increase in outdoor activities, more sunshine. 3. Hypoglycemia: If a one-and-a-half year old baby is not fed for a long time, it may lead to hypoglycemia, which is prone to the symptoms of sweating. Clinically there are many other reasons for babies to sweat profusely while sleeping, such as nightmares, hyperthyroidism, etc. It is recommended that if the baby sweats profusely and does not get relief after adjusting the temperature, he should seek medical treatment in a timely manner.