Journal of Applied Physiology, Vol 71, Issue 6 2518-2527, Copyright © 1991 by American Physiological Society

ARTICLES

Effects of cycle exercise on intestinal absorption in humans

C. V. Gisolfi, K. J. Spranger, R. W. Summers, H. P. Schedl and T. L. Bleiler
Department of Exercise Science and Gastroenterology, University of Iowa, Iowa City 52242.

Intestinal absorption was measured in six trained male cyclists during rest, exercise, and recovery periods with the segmental perfusion technique. Each subject passed a multilumen tube into the duodenojejunum. The experiments consisted of 1) a sequence of 1-h bouts of cycling exercise at 30, 50, and 70% maximal O2 uptake (Vo2max) separated by 1-h rest periods or 2) a 90-min bout at 70% VO2max. The cycling was performed on a constant-load Velodyne trainer. Absorption of water and a 6% carbohydrate-electrolyte (2% glucose, 6% sucrose, 20 meq Na+, 2.6 meq K+) solution (both perfused at 15 ml/min) were compared. The effects of perfusing an isotonic electrolyte solution during mild (30% VO2max) exercise were also studied. Fluid was sampled every 10 min from ports 10 and 50 cm distal to the infusion site. Water flux was determined by differences in polyethylene glycol concentration across the 40-cm test segment. Results showed 1) no difference in water or electrolyte absorption rates among rest, exercise, and recovery periods; 2) no difference in absorption rates among the three exercise intensities or different exercise durations; and 3) significantly greater fluid absorption rates from the carbohydrate-electrolyte (CE) solution than from water. Water flux during rest, exercise, and recovery was about sixfold greater from the CE solution than from the isotonic solution without carbohydrate. We conclude that 1) exercise has no effect on water or solute absorption in the duodenojejunum, 2) fluid absorption occurs significantly faster from a CE solution than from water, and 3) fluid absorption is increased sixfold by addition of carbohydrate to an electrolyte solution.

This article has been cited by other articles:

				C. V. Gisolfi Is the GI System Built For Exercise? Physiology, June 1, 2000; 15(3): 114 - 119. [Abstract] [Full Text] [PDF]

				S. H. Kreisman, A. Manzon, S. J. Nessim, J. A. Morais, R. Gougeon, S. J. Fisher, M. Vranic, and E. B. Marliss Glucoregulatory responses to intense exercise performed in the postprandial state Am J Physiol Endocrinol Metab, May 1, 2000; 278(5): E786 - E793. [Abstract] [Full Text] [PDF]

				P. Galassetti, K. S. Hamilton, F. K. Gibbons, D. P. Bracy, D. B. Lacy, A. D. Cherrington, and D. H. Wasserman Effect of fast duration on disposition of an intraduodenal glucose load in the conscious dog Am J Physiol Endocrinol Metab, March 1, 1999; 276(3): E543 - E552. [Abstract] [Full Text] [PDF]

				G. P. Lambert, R. T. Chang, T. Xia, R. W. Summers, and C. V. Gisolfi Absorption from different intestinal segments during exercise J Appl Physiol, July 1, 1997; 83(1): 204 - 212. [Abstract] [Full Text] [PDF]