In our previous review characteristics of the athlete's heart were divided into three groups: morphologic (left ventricular (LV) hypertrophy, improved coronary circulation), functional (better diastolic function) and regulatory (lower heart rate (HR)) features. In the present review, the influences of the types of sports and the age on the athlete's heart are discussed. Studies using echocardiographic, Doppler-echocardiographic, tissue Doppler imaging (TDI) and magnetic resonance imaging (MRI) results are mostly involved. The coronary circulation was investigated overwhelmingly in animal experiments. In the LV hypertrophy a major contributor is the increase of the LV wall thickness (WT) than that of the LV internal diameter (ID). A right ventricular (RV) hypertrophy can also be seen in athletes. Athletic features are induced mostly by endurance training. Approximately two years regular physical training is needed to develop characteristics of the athlete's heart, hence, in the young children they are less marked. LV hypertrophy and lower HR are characteristic in young and adult athletes, but they are less marked in older ones. A richer coronary capillary network can develop mostly at a young age.