Physiologic versus pathologic hypertrophy: endurance exercise and chronic pressure overload

Endurance exercise requires that the heart maintain a highly elevated cardiac output for an extended period of time, working against a slightly elevated afterload. Endurance athletes manifest a large ventricular volume, characterized on echocardiogram by an increased end-diastolic internal diameter and wall thickness. This article describes the structural, functional, and biochemical alterations in the heart as a result of the physiologic stress of exercise, along with the signaling mechanisms for these changes. The article also compares exercise-induced hypertrophy and hypertrophy from chronic pressure overload.