Abstract:

Background: Cardiac remodeling in response to long term athletic training has been a well-described phenomenon in humans which leads to myocardial adaptations, with remodeling of the cardiac chambers especially the left ventricle resulting in changes in heart rate and arterial blood pressure.

Aim / Objective: The aim of this study was to evaluate the effect of maximal exercise on the heart rate, blood pressure and level of cardiac remolding in elite athletes as compared to sedentary healthy subjects.

Place and Duration of Study: The present study was carried out at the Department of Physiology, Army Medical College, with collaboration of Armed Forces Institute of Cardiology (AFIC) Rawalpindi from June 2003 to May 2004.

Methodology: A total number of 44 subjects were included in this study. These comprised of 22 elite endurance athletes and 22 healthy sedentary volunteers as controls. All subjects were examined clinically to rule out the cardiovascular and pulmonary diseases on the basis of medical history, physical examination, and echocardiography. Heart rate was measured by auscultatory method at mid clavicular line in left fourth intercostal space before and within 3 minutes after exercise, Arterial blood pressure (mm Hg) was measured after 5 minutes of rest in a seated position by mercury sphygmomanometer. Mean arterial blood pressure was calculated as diastolic plus one third of pulse pressure where pulse pressure was taken as the systolic pressure minus diastolic pressure. The readings were taken before and within 3 minutes after exercise. All the selected subjects were examined on a Toshiba Power Vision 6000 echocardiograph for assessing and measuring their LV end-diastolic internal diameter (LVIDd), diastolic inter-ventricular septal thickness (IVSTd), diastolic posterior wall thickness (PWTd). The left ventricular mass (LVM) was calculated by using the Devereux formula. They were subjected to maximal exercise till exhaustion on electronically driven ergometer cycle before breakfast.

Results: It was observed that the heart rate and blood pressure of athletes were significantly less than the controls; while left ventricular end-diastolic internal diameter (LVIDd), diastolic inter-ventricular septal thickness (IVSTd), diastolic posterior wall thickness (PWTd), and mass (LVM) was greater in athletes in comparison to healthy controls..

Conclusion: The long term athletic training causes remodeling of the heart with increased dimensions of the left ventricle which reduces the heart rate and blood pressure in endurance trained athletes.

Keywords: The heart of trained athletes, Cardiac remodeling in athletes, Echocardiography of heart