AGING AND PHYSICAL-ACTIVITY DETERMINE CARDIAC STRUCTURE AND FUNCTION IN THE OLDER ATHLETE

To evaluate the effects of age and physical activity on cardiac structure and function, 45 ultraendurance athletes were compared with 24 sedentary control subjects. Two-dimensionally guided M-mode echocardiograms and pulsed Doppler studies of left ventricular inflow velocity were obtained. Both older and younger athletes differed from age-similar sedentary control subjects in having lower heart rates (56 vs. 72 beats/min, younger; 53 vs. 74 beats/min, older), larger left ventricular cavities at end diastole (5.4 vs. 4.9 cm younger; 5.4 vs. 4.9 cm, older), and higher ratios of early to atrial inflow velocities (2.14 vs. 1.37, younger; 1.32 vs. 0.83, older; all P < 0.05). Older athletes differed from younger athletes in having higher systolic and diastolic blood pressures (131/79 vs. 122/71 mmHg), greater posterior wall thickness (1.1 vs. 0.9 cm), lower rapid filling velocity (52 vs. 70 cm/s), higher atrial systolic velocity (41 vs. 34 cm/s), and lower early-to-atrial inflow velocity ratios (1.32 vs. 2.14, all P < 0.05). Thus the aging heart manifests structural and functional changes in response to physical activity that are similar but not identical to those seen in younger subjects. The expected pattern of cardiac alterations normally seen in response to age is modified in the older athlete, suggesting that exercise training, as well as aging, is an effective stimulus in shaping left ventricular structure and function in the older heart.