Vascular Function Changes Following An Acute Bout Of Resistance Exercise In Obese And Non-obese Males

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One of the earliest sub-clinical stages associated with atherosclerosis is endothelial dysfunction, which has been shown to predict future cardiovascular events. Chronic exercise is thought to improve vascular function (VF); however, few studies have evaluated the effects of acute resistance exercise (RE) on VF. In addition, there are no studies to date that have compared VF responses in obese and non-obese individuals following acute RE. PURPOSE: The purpose of this study was to evaluate VF, as determined by the assessment of forearm blood flow (FBF) and vascular reactivity (VR) before and after a single bout of RE in obese and non-obese males. METHODS: Seven non-obese (21.4 ± 2.1 yrs; 22.5 ± 1.2 kg/m2) and seven obese (23.8 ± 2.9 yrs; 36.3 ± 2.4 kg/m2) males volunteered to participate. FBF was assessed prior to (PRE) and immediately after (POST) 3 sets of arm curls to fatigue (70% of 1-RM) using strain-gauge plethysmography before and after 5 min of upper arm occlusion and subsequent reactive hyperemia. Total excess flow, calculated as the difference between baseline FBF and FBF during reactive hyperemia, was used as an indicator of VR. A One-Way ANOVA was performed to determine differences within each group. A multivariate ANOVA was used to test between-subject factors. RESULTS: In non-obese males, FBF was significantly increased in response to reactive hyperemia during the PRE (P = 0.021) and POST (P = 0.007) trials. However, this increase was not observed in obese males (PRE, P = 0.147; POST, P = 0.341). There was no significant difference observed in VR for both non-obese and obese males PRE and POST. Between-subject analysis revealed that only POST FBF (ml 100 ml-1 min-1 · s) was significantly different between non-obese and obese subjects at baseline (1782.7 ± 169.6 vs. 1272.1 ± 92.6, P = 0.021) and during reactive hyperemia (2796.4 ± 265.8 vs. 1503.5 ± 214.4, P = 0.003). Additionally, a significant difference in VR was observed between non-obese and obese males POST (1013.7 ± 208.5 vs. 231.4 ± 220.4, P =.024). CONCLUSIONS: VR was increased during reactive hyperemia following a single bout of RE in non-obese, but not obese males. The different responses suggest that adiposity may have a detrimental effect on VF during acute exercise. Future studies that investigate the effects of obesity on cardiovascular health are warranted.