Impaired left ventricular systolic function after a half-ironman race.
OBJECTIVE
To assess the effects of prolonged strenuous exercise in the form of a half-ironman (HI) race (2 km swim, 90 km bike ride and a 21 km run) on left ventricular systolic function.


RESULTS
The study participants consisted of nine male triathletes (mean age +/- SD 32+/-5 years) who competed in the Great White North HI race. Two-dimensional transthoracic echocardiograms were obtained two to three days before the HI (prerace), immediately after completion of the HI (postrace) and 24 h after cessation of exercise. Compared with before the race, performing an HI was associated with a decline in systolic blood pressure (prerace 127.2+/-15.0 mmHg compared with after the race 116.1+/-10.2 mmHg, P<0.05), the systolic blood pressure to end-systolic cavity area ratio (a surrogate for left ventricular contractility - prerace 14.3+/-3.0 mmHg/cm(2) compared with postrace 11.0+/-2.2 mmHg/cm(2), P<0.05) and the fractional area change (prerace 54.1+/-3.8% compared with postrace 47.4+/-5.5%, P<0.05). There was also a concomitant increase in heart rate (prerace 56.3+/-9.4 beats/min compared with postrace 74.1+/-10.7 beats/min, P<0.05), the end-systolic cavity area (prerace 9.2+/-2.2 cm(2) compared with postrace 10.8+/-1.9 cm(2), P<0.05) and the end-systolic cavity area to end-systolic myocardial area ratio (prerace 0.39+/-0.08 compared with postrace 0.51+/-0.1, P<0.05), which returned toward baseline values 24 h after cessation of the HI.


CONCLUSIONS
Performing an HI appears to be associated with a transient impairment in left ventricular contractility and a subsequent decline in left ventricular systolic function that tends to return toward normal values within 24 h after cessation of exercise.
Haykowsky
M
M
Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Canada. mark.haykowsky@ualberta.ca
Welsh
R
R
Humen
D
D
Warburton
D
D
Taylor
D
D
D000328:Adult; D000704:Analysis of Variance; D001642:Bicycling / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology; D004452:Echocardiography; D006801:Humans; D008297:Male; D009200:Myocardial Contraction / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D012420:Running / Q000502:physiology*; D013550:Swimming / Q000502:physiology*; D013599:Systole / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*