EFFECTS OF EXERCISE ON VASCULAR FUNCTION VARIES BETWEEN GENDERS

 Men and women demonstrate different vascular responses to exercise. Research findings on these differences will be presented at the 2000 Intersociety Meeting of the American Physiological Society in Portland, ME

 
Portland, ME—The incidence of atherosclerosis and coronary heart disease is less in pre-menopausal women than in men of comparable age. Similarly, women have lower maximal oxygen uptake/kg body weight than men. These gender-dependent differences may be caused in part by the result of differences in arterial vasoreactivity and arterial endothelium and vascular smooth muscle (VSM), says M. Harold Laughlin, Ph.D.   Dr. Laughlin, of the University of Missouri, Department of Veterinary Biomedical Sciences, will discuss these differences at the 2000 Intersociety Meeting of the American Physiological Society. The meeting, "The Integrative Biology of Exercise," is being held September 20-23, 2000 in Portland, ME.

Background: Female steroid hormones appear to modify the phenotype of the two types of cells that make up arteries (arterial VSM and endothelium). Gender influences endothelial function and gene expression. In several research models, endothelium-mediated vasodilation is more pronounced in the arteries of females than in the arteries of males.

This may be the result of estrogenic effects, since estrogen has been shown to increase expression of endothelial nitric oxide synthase (eNOS) in both arteries and cultured endothelial cells.  Estrogen also increases endothelium-mediated vasodilation in experimental models of arteries involving males and females.

Gender also appears to influence exercise training-induced adaptations of arterial vasomotor reactivity. These gender-dependent effects are the result of altered phenotype in both VSM and endothelium. Current evidence indicates that gender interacts with training-induced vascular adaptations differently depending on species, vasoactive agonists, and anatomic origin of arteries.

Dr. Laughlin’s research suggests that the positive effects of female gender and exercise on the cells that line skeletal muscle and coronary arteries interact, so that it is possible that being physically active has greater benefit for women than for men.  On the other hand, the fact that men do not have the beneficial effects of female gender on endothelial function may mean that exercise's effects are more important in men even if the result is not as great an improvement in endothelial function. More research is required to address these possibilities.

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