Fluid Restriction during Running Increases GI Permeability

Abstract

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.

Endurance swimming stimulates transepithelial calcium transport and alters the expression of genes related to calcium absorption in the intestine of rats

“…These genes could partially explain changes in water and electrolyte metabolism during exercise training (3). Upregulation of claudin-8, known to act as a paracellular cation barrier to Na ϩ , K ϩ , H ϩ , and NH 4 ϩ , as well as a regulator of epithelial integrity (1), may be a part of the compensatory change to prevent allergen leakage and intestinal hyperpermeability during exercise, as previously reported in humans and dogs (13,33). Furthermore, the epithelial integrity may be upheld by upregulating genes of local factors which could stimulate growth and differentiation of the intestinal epithelial cells, such as epimorphin and insulin (Supplemental Table S2; Refs.…”

“…Besides calcium absorption, endurance exercise has been reported to affect absorption of other electrolytes, nutrients, and water as well as intestinal permeability, presumably at the genomic level (3,19,33,53). Therefore, the genome-wide microarray study was performed in duodenal cells from control (n ϭ 6) and swimming rats (n ϭ 6) to demonstrate transcriptome responses after swimming.…”

“…Thus the enhanced calcium absorption associated with endurance swimming may also result from the altered expression of these genes. In addition, endurance exercise was known to induce transport of other ions and long-term metabolic changes in the intestinal epithelial cells (3,19,33,53). Thus a genome-wide study using microarray should help indentify other intestinal genes that were affected by endurance swimming.…”

Gastrointestinal Complaints During Exercise: Prevalence, Etiology, and Nutritional Recommendations

“…However, it must be noted that most studies used exercise intensities that were moderate and durations of exercise that were no longer than 2 h. It is feasible that, during higher intensities of exercise when intestinal blood flow is more compromised, and also after more prolonged exercise, that absorption could be reduced. It has also been reported that with fluid restriction intestinal permeability may be increased [35], possibly because dehydration ultimately influences gut perfusion.…”

Estrategias de suplementacion y función gastrointestinal en atletas de resistencia

“…Posteriores investigaciones en el área han concluyen que periodos cortos de carrera pueden provocar disfunción de la barrera intestinal bajo ciertas circunstancias; por ejemplo, se vio que correr durante 60 minutos al 70% del VO 2 máx bajo condición de restricción de fluidos 13 o después del consumo de aspirina o ibuprofeno a dosis terapéutica 24 horas aminoácidos del fluido extracelular y más del 60% del contenido de aminoácidos libres del músculo esquelético. La concentración plasmática en ayunas de glutamina (p[Gln]) es de 500-700μmol/l y es frecuentemente más alta en atletas, alcanzando concentraciones de 20mM.…”