| Popis: |
Endothelial dysfunction, or the inability of an artery to dilate sufficiently when subjected to excessive shear stress, serves both as a predictor of future cardiovascular events as well as an early indication of atherosclerosis. Several chronic disease states, including obesity, have been shown to alter endothelial function, which may be mediated through circulating pro- and anti-inflammatory adipokines. Still, the mechanisms by which obesity-related low-grade inflammation alters endothelial function are not fully elucidated. Acute and chronic endurance exercise training has previously been shown to be effective in improving endothelial function; however, chronic resistance exercise training is not universally regarded as beneficial to vascular functioning. Far fewer studies have examined the effect of acute resistance exercise on vascular function and adipokine release. To further understand the effects of resistance exercise training on vascular function, a meta-analysis was completed to examine the effects of resistance training on brachial artery flow mediated dilation (FMD), a common measure of endothelial function. The results of the meta-analysis indicate that resistance training has a small positive effect on FMD. Additionally, the effects of an acute bout of lower body resistance exercise on forearm blood flow (FBF) and two inflammatory cytokines were evaluated in obese (>30% body fat) and non-obese (≤30% body fat) subjects. It was hypothesized that the resistance exercise bout would increase FBF, that those changes would be greater in obese versus non-obese subjects, and that the changes in circulating cytokines (adiponectin and tumor necrosis factor-α) would be related to changes in FBF. The results indicate that FBF measures in obese and non-obese subjects react in a divergent pattern immediately following resistance exercise but return to baseline within 24 hours. These changes were not related to changes in adiponectin or TNF-α although changes in adiponectin were related to changes in TNF-α. In conclusion, resistance exercise training programs may have a small positive effect on vascular function which may reduce overall cardiovascular disease risk. Additionally, obese and non-obese subjects display differing patterns of vascular responses to an acute bout of resistance exercise, supporting the view that obesity, and its associated low-grade inflammatory response, may negatively alter vascular homeostasis. |
