Changes in vascular and cardiac function after prolonged strenuous exercise in humans

Abstract

DJ. Changes in vascular and cardiac function after prolonged strenuous exercise in humans. J Appl Physiol 105: 1562-1568. First published August 21, 2008 doi:10.1152/japplphysiol.90837.2008.-Prolonged exercise has been shown to result in an acute depression in cardiac function. However, little is known about the effect of this type of exercise on vascular function. Therefore, the purpose of the present study was to investigate the impact of an acute bout of prolonged strenuous exercise on vascular and cardiac function and the appearance of biomarkers of cardiomyocyte damage in 15 male (32 Ϯ 10 yr) nonelite runners. The subjects were tested on two occasions, the day before and within an hour of finishing the London marathon (229 Ϯ 38 min). Function of the brachial and femoral arteries was determined using flow-mediated dilatation (FMD). Echocardiographic assessment of cardiac strain, strain rate, tissue velocities, and flow velocities during diastole and systole were also obtained. Venous blood samples were taken for later assessment of cardiac troponin I (cTnI), a biomarker of cardiomyocyte damage. Completion of the marathon resulted in a depression in femoral (P ϭ 0.04), but not brachial (P ϭ 0.96), artery FMD. There was no change, pre-vs. postmarathon, in vascular shear, indicating that the impaired femoral artery function was not related to hemodynamic changes. The ratio of peak early to atrial radial strain rate, a measure of left ventricular diastolic function, was reduced postmarathon (P ϭ 0.006). Postrace cTnI was elevated in 12 of 13 runners, with levels above the recognized clinical threshold for damage in 7 of these. In conclusion, when taken together, these data suggest a transient depression in cardiac and leg vascular function following prolonged intensive exercise. cardiovascular; exercise; marathon; ultrasound; troponins EPIDEMIOLOGICAL (7, 33) and experimental (18) evidence supports the public health message that exercise training and physical activity have substantial vascular and cardiac health benefits, with an ϳ30% reduction in cardiac risk (39). Despite this, it is clear that acute exercise transiently elevates the risk of cardiac events (37), or even sudden cardiac death (SCD) (40), in those at risk. The cardiovascular and physiological responses to prolonged exercise that are implicated in this transient period of increased cardiovascular risk are not well understood.Previously, we and others have demonstrated that marathon running results in a modest depression in cardiac function, primarily observed in indexes of left ventricular diastolic function (12,28,29). This is associated with the sporadic appearance of biomarkers of cardiomyocyte damage (10,12,26,28,29,34). However, the changes in cardiac function after prolonged strenuous exercise that occur in different planes of motion (radial, circumferential, and longitudinal) have not previously been studied.Vascular endothelial function reflects the health of the vessel wall. The dilator response to a 5-min ischemic period, termed flow-me...

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