What is exercise induced remodeling of the heart?

What is exercise induced remodeling of the heart?

Repetitive participation in vigorous physical exercise is associated with significant changes in structure and function of the heart. This is known as exercise induced remodeling of the heart. It is characterized by thickening of the left ventricle with or without enlargement of the cavity of the left ventricle. Left ventricle is the lower muscular chamber of the heart which pumps blood to the whole body. Exercise induced remodeling of the heart is associated with changes in both the pumping function and the relaxation of the heart muscle.

Enlargement of the heart in trained athletes have been documented as early as 1899. They noted enlargement of the heart outline in skiers and rowers. Features of athlete’s heart include balanced enlargement of both right and left ventricles, mild to moderate increase in thickness of the wall of the left ventricle and enlargement of both right and left atrium. Right ventricle is the right lower chamber of the heart which pumps blood returning from the body, to the lungs for oxygen enrichment. Right atrium is the right upper chamber which receives the blood returning from the various parts of the body and passes to the right ventricle. Left atrium is the left upper chamber which receives the blood returning from the lungs after oxygen enrichment and passes on to the left ventricle.

The extent of exercise induced changes in heart muscle depends on the intensity, frequency and duration of exercise. Exercise induced changes in heart muscle can also occur in adults with moderate physical activity. In a study of over 1000 healthy persons using magnetic resonance imaging (MRI), it was shown that increasing physical activity was associated with increase in the mass of the left ventricle and increase in volumes of both ventricles. The effect of physical activity on structure of the heart was larger than that of increased blood pressure and similar to that of age.

Regular physical activity is strongly associated with reduction in all cause mortality compared to a sedentary lifestyle  and even moderate physical activity. The proposed mechanisms are a relative decrease in oxygen demand of the heart muscle, better blood flow to the heart muscle and lower risk factors for heart disease like high blood pressure, high blood sugar and obesity.