The effect of physical exercise on parameters of gastrointestinal function

Exercise decreases splanchnic bloodflow. Therefore exercise may induce alterations in gastrointestinal (GI) function. In the present study we investigated the effect of high-intensity exercise on oesophageal motility, gastro-oesophageal reflux, gastric pH, gastric emptying, orocaecal transit time (OCTT), intestinal permeability and glucose absorption simultaneously, using an ambulatory protocol. Ten healthy well-trained male subjects underwent a rest-cycling-rest, and a rest-rest-rest protocol (60-90-210 min). Oesophageal motility, gastro-oesophageal reflux and intragastric pH was measured using a trans-nasal catheter. OCTT was measured via breath H2 measurement. A sugar absorption test was applied to determine intestinal permeability and glucose absorption. Gastric emptying was measured using the 13C-acetate breath test. Peristaltic velocity was increased during cycling, compared to rest (4.92 (2.86) vs. 4.03 (1. 48) cm s-1, P = 0.015). Peristaltic contraction pressure at the mid-oesophagus and the duration of the peristaltic contractions at the mid- and distal oesophagus was lower during cycling. There were no differences between the pre-exercise, the exercise and the post-exercise episodes for gastric pH or for both the number and duration of reflux episodes, in both the rest and cycling trials. Neither gastric emptying nor OCTT showed differences between rest and cycling. The lactulose/rhamnose ratio and intestinal glucose absorption were significantly decreased in the cycling trial. Our model enables multiple GI-measurements during exercise. Cycling at 70% Wmax does not lead to differences in reflux, gastric pH or gastrointestinal transit in healthy trained individuals. The distal oesophageal pressure decreases and peristaltic velocity increases. The lactulose/rhamnose ratio and jejunal glucose absorption are decreased during exercise.