Evidence of impaired left ventricular performance after an uninterrupted competitive 24 hour run

Abstract

The effect of extremely exhaustive exercise on left ventricular performance was studied echocardiographically in 13 experienced male ultramarathon runners who took part in a competitive 24 hr run, completing distances of 114 to 227 km. Although the left ventricular end-diastolic dimension (EDD) was reduced by 7% (54 ± 5 to 50 ± 7 mm; p < .005), the end-systolic dimension (ESD) increased slightly (33 ± 5 to 34 ± 6 mm; NS). As a consequence, the stroke dimension (21 ± 2 to 16 ± 2 mm; p < .005) and fractional shortening (38 ± 5% to 32 ± 5%; p < 0.005) declined by 24% and 16%, respectively. The reduction in fractional shortening was related to ΔESD (r = -.66; p < .05) but not to ΔEDD (r = .22; NS). In spite of reduced afterload, the mean velocity of circumferential fiber shortening also decreased by an average of 9% (9 < .01) in proportion to the distance completed (r = -.69; p