6533b821fe1ef96bd127b606

RESEARCH PRODUCT

Beta-receptor desensitization evoked by a multistage ultralong distance exercise in the desert?

subject

description

Background Few studies addressed to the evolution of cardiac function during a multistage ultra-long duration exercise (MULDE). Methods Serial echocardiographic assessment of cardiac function was performed in male healthy subjects during the 2014 Marathon des Sables before the race (T1), at the second (T2) and fifth (T3) arrival (236 km) then after 48 h recovery. Analysis were performed by 2 sonographers blind for the results of the other and the time of measure. Statistical analysis was performed using ANOVA-RM to compare the evolution of the different parameters. Results Among the 20 athletes, 18 completed the study (mean age 42.4, median 42). RR intervals and (Left ventricular End Diastolic Volume (Simpson) (LVEDV) changed during the race and were correlated (r2 = 0.539, P  Table 1 ). Conclusions 48 h after a MULDE, we observed a drop in heart rate and contractility response to preload. The evolution of these parameters could be explained by a beta-receptors desensitization. These data need to be confirmed by other studies.