Fluid Restriction during Running Increases GI Permeability

• Published in: International journal of sports medicine 2008-03, Vol.29 (3), p.194-198
• Main Authors: Lambert, G. P., Lang, J., Bull, A., Pfeifer, P. C., Eckerson, J., Moore, G., Lanspa, S., O'Brien, J.
• Format: Article
• Language: English
• Subjects: Adult; Double-Blind Method; Duodenum - metabolism; Female; Gastrointestinal Agents - pharmacokinetics; Gastrointestinal Agents - urine; Glucose Solution, Hypertonic - pharmacokinetics; Humans; Intestinal Absorption - physiology; Intestine, Small - metabolism; Lactulose - pharmacokinetics; Lactulose - urine; Male; Permeability; Physiology & Biochemistry; Rest - physiology; Rhamnose - pharmacokinetics; Rhamnose - urine; Running - physiology; Sucrose - pharmacokinetics; Sucrose - urine; Sweetening Agents - pharmacokinetics; Water Deprivation
• ISSN: 0172-4622; 1439-3964
• DOI: 10.1055/s-2007-965163

Abstract The purpose of this study was to determine gastrointestinal (GI) permeability during prolonged treadmill running (60 min at 70 % V·O 2max ) with and without fluid intake (3 ml/kg body mass/10 min). Twenty runners (11 males, 9 females; age = 22 ± 3 (SD) yrs; mean V·O 2max = 55.7 ± 5.0 ml/kg/min) completed four experiments: 1) rest, 2) running with no fluid (NF), 3) running with ingestion of a 4 % glucose solution (GLU), and 4) running with ingestion of a water placebo (PLA). To determine GI permeability, subjects also drank a solution containing 5 g sucrose (S), 5 g lactulose (L), and 2 g rhamnose (R) immediately prior to each trial. Gastroduodenal permeability was determined by urinary S excretion, while small intestinal permeability was determined by the L/R excretion ratio. Percent body mass loss (i.e., dehydration) was negligible during rest, GLU and PLA, while NF resulted in a 1.5 % loss of body mass (p < 0.05). Gastroduodenal and intestinal permeability were significantly (p < 0.008) increased in NF compared to rest. There were no other differences in GI permeability. These results indicate that fluid restriction during 1 h of steady-state running increases GI permeability above resting levels.