The Effect of Exercise Intensity on Endothelial Function in Physically Inactive Lean and Obese Adults |
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Authors: | Rachel Hallmark James T Patrie Zhenqi Liu Glenn A Gaesser Eugene J Barrett Arthur Weltman |
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Institution: | 1. Department of Human Services, University of Virginia, Charlottesville, Virginia, United States of America.; 2. Department of Public Health Sciences, University of Virginia, Charlottesville, Virginia, United States of America.; 3. Department of Medicine, University of Virginia, Charlottesville, Virginia, United States of America.; 4. General Clinical Research Center, University of Virginia, Charlottesville, Virginia, United States of America.; Medical University Innsbruck, Austria, |
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Abstract: | PurposeTo examine the effects of exercise intensity on acute changes in endothelial function in lean and obese adults.MethodsSixteen lean (BMI <25, age 23±3 yr) and 10 obese (BMI >30, age 26±6 yr) physically inactive adults were studied during 3 randomized admissions control (C, no exercise), moderate-intensity exercise (M, @ lactate threshold (LT)) and high-intensity exercise (H, midway between LT and VO2peak) (30 min)]. Endothelial function was assessed by flow-mediated dilation (FMD) at baseline and 1, 2, and 4 h post-exercise.ResultsRM ANCOVA revealed significant main effects for group, time, and group x condition interaction (p<0.05). A diurnal increase in FMD was observed in lean but not obese subjects. Lean subjects exhibited greater increases in FMD than obese subjects (p = 0.0005). In the obese group a trend was observed for increases in FMD at 2- and 4-hr after M (p = 0.08). For lean subjects, FMD was significantly elevated at all time points after H. The increase in FMD after H in lean subjects (3.2±0.5%) was greater than after both C (1.7±0.4%, p = 0.015) and M (1.4±0.4%, p = 0.002). FMD responses of lean and obese subjects significantly differed after C and H, but not after M.ConclusionIn lean young adults, high-intensity exercise acutely enhances endothelial function, while moderate-intensity exercise has no significant effect above that seen in the absence of exercise. The FMD response of obese adults is blunted compared to lean adults. Diurnal variation should be considered when examining the effects of acute exercise on FMD. |
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