BACKGROUND: Endothelial function deteriorates after glucose ingestion. This may be attributed to hyperglycemia-induced oxidative stress. Acute endurance exercise might improve postprandial endothelial function by enhancing glucoregulation and reducing postprandial hyperglycemia. OBJECTIVE: The objective was to determine whether endurance exercise performed 17 h before high-sugar-food ingestion attenuates postprandial impairment in endothelial function. DESIGN: Healthy men and women (n = 13; age: 48 +/- 17 y) were studied on 2 occasions: after > or = 48 h with no exercise and 17 h after a 60-min bout of endurance exercise. During each trial, brachial artery flow mediated dilation (FMD) was used to assess endothelial function before and after the ingestion of a candy bar and soft drink. Glucose, insulin, and thiobarbituric acid-reactive substances (TBARS), a marker of oxidative stress, were measured in blood obtained during each FMD measurement. The insulin sensitivity index was calculated from the glucose and insulin data. RESULTS: FMD decreased significantly after food ingestion in both trials. However, prior exercise shifted the entire FMD curve upward (main treatment effect: P = 0.0002), which resulted in a greater area under the curve for FMD (774 +/- 122.min) than did no exercise (607 +/- 122.min) (P = 0.01). Prior exercise shifted the glucose and insulin curves downward (main treatment effects: P = 0.05 and P = 0.0007, respectively) and resulted in a significantly greater insulin sensitivity index (10.8 +/- 0.7) than did no exercise (9.2 +/- 0.7) (P = 0.01). TBARS did not differ significantly between trials. CONCLUSION: Postprandial endothelial function was improved by endurance exercise performed approximately 17 h earlier. This effect was accompanied by exercise-induced improvements in insulin action and reductions in glycemia, but did not correspond with reductions in oxidative stress, as assessed by TBARS.
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