In briefThe effects of physical training include cardiovascular and specific muscle adaptation, decreased resting heart rate, and increased cardiac size, stroke volume, maximum cardiac output, blood volume, vagal tone, and maximum breathing capacity. Young athletes with heart disease can generally participate in sports, but there is a wide spectrum of ability among them. The treadmill exercise test should be used to establish exercise norms. Children with severe mitral stenosis, aortic stenosis, idiopathic hypertrophic subaortic stenosis, active myocarditis, pulmonary hypertension, and significant arrhythmias should not participate in strenuous sports. Others with cardiac problems should be encouraged to participate for enjoyment rather than winning.