The effect of physical exercise on parameters of gastrointestinal function

Exercise decreases splanchnic bloodflow. Therefore exercise may induce alte rations in gastrointestinal (GI) function. In the present study we investig ated the effect of high-intensity exercise on oesophageal motility, gastro- oesophageal reflux, gastric pH, gastric emptying, orocaecal transit time (O CTT), 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-oeso phageal reflux and intragastric pH was measured using a trans-nasal cathete r. OCTT was measured via breath H-2 measurement. A sugar absorption test wa s applied to determine intestinal permeability and glucose absorption. Gast ric emptying was measured using the C-13-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 pressur e at the mid-oesophagus and the duration of the peristaltic contractions at the mid- and distal oesophagus was lower during cycling. There were no dif ferences between the pre-exercise, the exercise and the post-exercise episo des 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 show ed differences between rest and cycling. The lactulose/rhamnose ratio and i ntestinal glucose absorption were significantly decreased in the cycling tr ial. 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 de creases and peristaltic velocity increases. The lactulose/rhamnose ratio an d jejunal glucose absorption are decreased during exercise.