<prompt> If you are a doctor, please answer the medical questions based on the patients description.Hi my son who is 8 keeps telling me that in gym class he gets chest pain while running,today was a gym day and told me he didnt have the pain but saw black for a minute...i think the gym teacher is pushing too hard but i dont really want to overlook it either..what to do.  <response>: Respected user, hi I evaluated your query thoroughly.Chest pain is due to decreased lung compliance in regard to exertion given by the body relates to - decreased oxygenation - excess mouth breathing - low levels of Hemoglobin, lack of proteins, trace elements, vitamins, minerals.Black out vision is related to decreased perfusion levels mostly deny Chat Doctor. What all you have to do is : Make him properly HY 