When a 10-year-old child has stomach pain when running, it is mostly due to transient ischemia or insufficient supply of blood to the intestines inside the abdominal cavity, which causes abdominal pain. Once the child stops running or rests or sits down, the blood flow inside the abdominal cavity increases again, and then the abdominal pain will be reduced or even disappear. This is because in the process of running the blood flow will flow more to the extremities, while the blood flow in the abdominal cavity will be reduced, resulting in a relative decrease in the blood flow in the abdominal cavity or ischemia, which is generally not a big problem for the patient, and will disappear after a certain age and normal vascular development. If it does not disappear repeatedly, it is time to see a vascular surgeon to see if there is stenosis or dysplasia of the mesenteric vessels.