Fluid restriction during running increases GI permeability.
The purpose of this study was to determine gastrointestinal (GI) permeability during prolonged treadmill running (60 min at 70 % V.O2max) 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.O2max = 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.
Lambert
G P
GP
Exercise Science and Athletic Training, Creighton University, Omaha, Nebraska 68178, United States. plambert@creighton.edu
Lang
J
J
Bull
A
A
Pfeifer
P C
PC
Eckerson
J
J
Moore
G
G
Lanspa
S
S
O'Brien
J
J
D000328:Adult; D004311:Double-Blind Method; D004386:Duodenum / Q000378:metabolism; D005260:Female; D005765:Gastrointestinal Agents / Q000493:pharmacokinetics / Q000652:urine; D005950:Glucose Solution, Hypertonic / Q000493:pharmacokinetics; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology*; D007421:Intestine, Small / Q000378:metabolism; D007792:Lactulose / Q000493:pharmacokinetics / Q000652:urine; D008297:Male; D010539:Permeability; D012146:Rest / Q000502:physiology; D012210:Rhamnose / Q000493:pharmacokinetics / Q000652:urine; D012420:Running / Q000502:physiology*; D013395:Sucrose / Q000493:pharmacokinetics / Q000652:urine; D013549:Sweetening Agents / Q000493:pharmacokinetics; D014868:Water Deprivation
D005765:Gastrointestinal Agents; D005950:Glucose Solution, Hypertonic; D013549:Sweetening Agents; D007792:Lactulose; D013395:Sucrose; D012210:Rhamnose