Children sleeping on their stomachs is a sleeping habit, in a short period of time is generally not harmful, if a long time sleeping on their stomachs will affect the breathing and blood circulation of the heart. 1. Breathing: prolonged sleeping on the stomach, most of the body weight will compress the diaphragm and chest, symptoms of respiratory distress, and sometimes lead to mouth and nose breathing problems. 2. Heart circulation: sleeping on your back for a long time will also lead to thoracic compression of the heart, increasing the load on the heart, and bad breathing will also affect blood circulation. If the child sleeps on his stomach for a long time may cause the above effects on the body, but most children will switch the sleeping position when sleeping, so there is no need to worry, parents should guide the child to develop the habit of lying on his back or side.