title: Effect of exercise intensity on active and passive glucose absorption.
abstract: The purpose of this study was to determine the effects of exercise intensity on active and passive intestinal glucose absorption. Eight trained runners (age = 23 +/- 2 y; VO2max = 62.1 +/- 5.8 mL x kg(-1) x min(-1)) performed a 1 h resting experiment and three 1 h treadmill experiments at 30, 50, or 70% VO2max in a thermoneutral environment. Immediately prior to each experiment, euhydrated subjects ingested a solution containing two non-metabolizable glucose analogs, 3-O-methyl-D-glucose (3MG; actively absorbed; 5 g) and D-xylose (passively absorbed; 5 g). During the following 5 h, all urine was collected and the amount of 3MG and D-xylose in the urine was determined. Using repeated measures ANOVA, a significant (P < 0.05) reduction in urinary excretion of each carbohydrate was observed at 70% VO2max compared to the other intensities suggesting that both active and passive intestinal absorption of glucose may be reduced during prolonged running at this intensity.
authors.affiliation: Dept of Exercise Science and Athletic Training, Creighton University, Omaha, NE 68178, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Lang
authors.forename: Carl V
authors.initials: CV
authors.lastname: Gisolfi
authors.forename: G Patrick
authors.initials: GP
authors.lastname: Lambert
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000493:pharmacokinetics* / Q000652:urine; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005947:Glucose / Q000378:metabolism / Q000493:pharmacokinetics*; D006029:Glycosuria; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D010101:Oxygen Consumption; D012420:Running
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D005947:Glucose