Exercise and the Endothelium

The vascular endothelium is a single layer of cells that lines the luminal surface of blood vessels. Changes in blood flow alter the frictional force (shear stress) of the blood against endothelial cells resulting in biochemical signaling. Chronically, the magnitude and pattern of shear stress to which the endothelium is exposed play a key role in determining its function and structure. Regular exercise reduces cardiovascular disease risk, and the multifaceted mechanisms of this beneficial effect likely include improvements in endothelial function, mediated at least in part by exercise-induced elevations in shear stress. In the first part of this chapter, we summarize the role of endothelial function in atherosclerosis development, describe the ways in which endothelial function is quantified in humans, and review the relationship between indices of endothelial function and cardiovascular event risk. The remainder of the chapter is devoted to reviewing the evidence regarding the impact of exercise training on endothelial function in different populations and the mechanisms that might mediate the beneficial effects of exercise.