PHYSIOLOGICAL CARDIAC REMODELING IN ENDURANCE ATHLETES: A NARRATIVE REVIEW

Abstract

Exercise-induced physiological cardiac remodeling represents a set of structural and functional adaptations that occur in the myocardium in response to chronic and intense physical training, being particularly evident in endurance athletes. This phenomenon reflects the plasticity of the cardiovascular system in response to the high metabolic demands imposed by prolonged aerobic exercise, characterized by sustained increases in cardiac output associated with maintenance or reduction of peripheral vascular resistance. In this hemodynamic context, a chronic volume overload is established, acting as the primary mechanical stimulus for myocardial fiber stretching and triggering a relatively balanced cardiac remodeling process involving expansion of the four cardiac chambers. Among these structural adaptations, the left ventricle plays a central role in optimizing cardiovascular performance. One of the most notable manifestations of this process is the increase in stroke volume, resulting from enlargement of the ventricular cavity combined with increased myocardial compliance, allowing the heart to eject greater volumes of blood without compromising systolic function. Consequently, an increase in left ventricular end-diastolic volume is observed, representing a fundamental mechanism for generating higher cardiac outputs during physical exertion. From a structural perspective, the most characteristic adaptation observed in endurance athletes is eccentric left ventricular hypertrophy, a geometric pattern defined by dilation of the ventricular cavity accompanied by proportional increases in myocardial mass and wall thickness. This pattern results primarily from the chronic volume overload associated with endurance exercise and allows ventricular expansion without loss of contractile efficiency. Evidence derived from echocardiographic and cardiac magnetic resonance studies demonstrates that this remodeling is characterized by increased cardiac chamber dimensions and elevated left ventricular mass, representing the predominant phenotype of cardiac adaptation in endurance athletes.