One year old babies sweating a lot may be related to the amount of activity, environmental factors, lack of vitamin D and so on. 1. Activity: one year old babies love to play, activity is relatively large, small children’s metabolism is vigorous, easy to appear sweaty phenomenon. 2. Environmental factors: baby sweating may also be related to environmental factors, such as high room temperature, the baby wears too many clothes, etc., can cause baby sweating. 3. Lack of vitamin D: Vitamin D deficiency, if not timely supplementation of vitamin D, there may be excessive sweating, sleep disturbance, irritability and so on. One year old baby sweating more may also have 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’s treatment.