IMPACT OF MARATHON RUNNING ON ENDOTHELIAL FUNCTION AND SUBCLINICAL ATHEROSCLEROSIS

Objective: Aerobic exercise has beneficial effects on the cardiovascular system. Marathon running is both an aerobic but also an extremely vigorous exercise. Endothelial function and carotid subclinical atherosclerosis are independent predictors of cardiovascular risk. We sought to investigate the chronic alterations of these indices in marathon runners. Design and method: We studied 30 marathon runners and 20 age- and sex-matched recreationally active control subjects. Endothelial function was evaluated with brachial flow-mediated dilatation (FMD) and early atherosclerosis with carotid intima-media thickness (cIMT). Results: Marathon runners had significantly higher systolic and pulse pressure compared to controls. They also had reduced body-mass index, waist to hip ratio and heart rate compared to controls (p < 0.05, for all). Common cIMT was significantly lower in athletes than controls (0.56 ± 0.11 vs. 0.63 ± 0.07, p = 0.029), while there was no difference in carotid bulb IMT between groups. FMD was higher in marathon runners compared to controls and nitrate-mediated dilatation (NMD) was similar in the two groups (9.0 ± 3.7 vs. 6.4 ± 1.7 and 12.6 ± 5.7 vs. 12.3 ± 3.4; p = 0.002 and p = 0.821, respectively). (Figure) We also observed a reverse U-shaped curve between endothelial function and amount of exercise. FMD was significantly inversely associated with the number of training days per week (r = -0.430, p = 0.018).Conclusions: Marathon runners have higher FMD compared to controls, indicating better vascular endothelial function, and also have lower cIMT compared to controls. Increased amount of exercise training seems to eradicate the beneficial effect of exercise on endothelial function. These findings provide further insights in the effects of marathon running on cardiovascular risk.