Effect of dehydration on gastrointestinal function at rest and during exercise in humans

Abstract

Dehydration leads to the aggravation of gastrointestinal (GI) complaints during exercise. The aim of this study was to examine the effect of dehydration on various GI parameters during strenuous exercise. Ten healthy well-trained men were investigated in dehydrated and in euhydrated conditions. Dehydration took place before the experiments using a dehydration regimen in a sauna leading to a 3% loss of body mass. Each experiment consisted of 1 h pre-exercise rest, 1.5 h cycling at 70% maximal exercise intensity, and 3.5 h post-exercise rest. During cycling, liquid gastric emptying (GE), orocaecal transit time (OCTT) and intestinal permeability and glucose absorption were measured. The GI-symptoms were scored using a questionnaire. Body temperature, plasma volume and vasopressin were measured before and after cycling. The GE was significantly slower during dehydration [median time to peak 13C enrichment in the breath sample (13C-TTP) 23.6 min, range 13.7-50.0 min, P = 0.02] than in the control situation (median 13C-TTP 17.1 min, range 9.8-38.4 min). The OCTT was unchanged (median 173 min, range 98-263 min compared to median 128 min, range 98-195 min, P = 0.18). Dehydration did not change intestinal permeability, glucose absorption, plasma volume, rectal temperature or plasma vasopressin concentration. In the dehydration experiment, exercise induced a significant increase in nausea (P = 0.01) and epigastric cramps (P = 0.05), in contrast to the control situation. In both experiments, exercise led to a significant increase in rectal temperature and plasma vasopressin concentration, and a significant decrease in plasma volume. The increase in plasma vasopressin concentration was significantly higher in the dehydration experiment (P = 0.015). No significant differences in either the post-exercise rectal temperatures or in plasma volumes was observed. The difference in GE between the two experiments was significantly correlated with the difference in nausea score (r = 0.87, P = 0.002). We concluded that dehydration leads to a delayed GE but not to differences in OCTT, intestinal permeability or glucose uptake during intense cycling. The delay in GE is significantly associated with an increase in exercise-induced nausea.

Gastric Emptying After Pickle-Juice Ingestion in Rested, Euhydrated Humans

“…We designed our experiment in this manner to increase its internal validity. Both exercise 16,41 and hypohydration 42 can negatively influence the GER of a fluid. If we had added these variables, we might have confounded the results of our original research questions.…”

Demographic and Epidemiologic Features of Acute Appendicitis

“…In a study by Brummer, a significant relationship was observed between humidity and AA, and it was reported, in their study on the physiology of hunger, that a decrease in body fluid loss, fecal stasis, and fecal dehydration prepared the ground for inflammation (Brumer, 1970). In contrast, van Nieuwenhoven et al reported that changes in intestinal system functions such as intestinal permeability and orocaecal transit time were not the reason for dehydration occurring (van Nieuwenhoven et al, 2000). We also determined, during a 4-year (2004-2007) study using meteorological data in our region, that such data as moisture and amount of rain did not have an effect on the frequency of AA (Table 3).…”

Exercise-Associated Hyponatremia

“…In this setting, even small increases in plasma AVP levels can cause significant water retention and hyponatremia, especially in combination with excessive water intake. Furthermore, gastrointestinal blood flow and water absorption from the stomach and intestine may be impaired during exercise (73). When the athlete stops activity, water absorption may increase rapidly and significantly (73).…”

“…Furthermore, gastrointestinal blood flow and water absorption from the stomach and intestine may be impaired during exercise (73). When the athlete stops activity, water absorption may increase rapidly and significantly (73). In the setting of elevated AVP levels, this rapid absorption of large quantities of water or hypotonic fluids can lead to significant falls in serum sodium.…”