yes, it has happened, but however it is very rare. The rare heart attack at a young age could be caused by a heart defect. In hot weather and with high physical activity and exertion, there could be a heat stroke attack which can resemble heart attacks. When you go to your doctor for a physical exam, the doctor should check your heart and blood pressure for anything unusual. When doing physical activity, drink water to keep hydrated, if you feel any chest pain or shortness of breath, then reduce your activity levels.