Cardiac hypertrophy and function in master endurance runners and sprinters

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Abstract
Cardiac enlargement with increased left ventricular mass is a recognized adaptive response to intensive physical conditioning. There have been few reports regarding cardiac hypertrophy and function in the middle-aged or older athlete. Accordingly, we studied 9 male Masters Track endurance distance runners (E) (mean age 54 yr) and 13 male Masters Track sprinters (S) (mean age 47 yr) by M-mode echocardiography, systolic time intervals, and maximal treadmill stress testing with direct measurement of maximal O2 consumption (VO2max). Left ventricular mass (LVM) index for E (154.0 +/- 27.4 g/m2; mean +/- SD) was greater than for S (127.1 +/- 15.9 g/m2) (P less than 0.05). LVM index was greater for both groups compared with age-range matched controls (N = 111.7 +/- 23.8 g/m2) (P less than 0.02). VO2max was greater in E (54 +/- 12 ml X kg-1 X min-1) than S (47 +/- 7 ml X kg-1 X min-1) (P less than 0.05) despite the younger age of S (P less than 0.05); both E and S had greater VO2max than predicted for nonathletic males of equivalent age. There was no significant linear relationship for LVM index and VO2max in the athletes. Left ventricular function at rest was normal. Thus, in well-trained older (greater than or equal to 40 yr) male distance runners and sprinters VO2max and LVM index are greater in E than S, and each greater than in controls, resting left ventricular function is normal, as judged by fractional shortening and systolic time intervals, and the degree of hypertrophy (LVM index) does not directly correlate with aerobic capacity (VO2max).