Long-term athletic activity causes morphological and functional changes in the heart characterized as left ventricle cavity dimension changes, wall thickness and mass increase and rhythm conduction changes. This condition is identified as “athlete’s heart syndrome”. The changes that are seen clinically occur as a result of physiological adaptation to exercise. Cardiovascular adaptation depends on the exercise’s type as well as its frequency, duration and intensity. In the athlete’s physical examination, various changes can be seen that are mistaken with pathological conditions. In addition, there are changes present due to cardiac hypertrophy, increased vagal tone and repolarization. The knowledge and recognition of the organic and functional changes developing in the athlete’s heart is being helpful to differentiate physiological changes from cardiac pathologies that can cause sudden death in athletes.