Effect of graded exercise on esophageal motility and gastroesophageal reflux in nontrained subjects

Abstract

The effects of graded exercise on esophageal motility and gastroesophageal reflux were evaluated in nine nontrained subjects, using a catheter with three strain-gauge transducers connected to a solid-state datalogger and an ambulatory intraesophageal pH monitor. Subjects exercised on a stationary bike at 45%, 60%, 75%, and 90% of peak O₂ uptake ( $\dot V$ O₂ max). Durations of exercise sessions and rest periods varied among subjects. Studies were performed after an overnight fast and subjects received only intravenous infusion of 5% glucose solution during the study. Plasma concentrations of gastrin, motilin, glucagon, pancreatic polypeptide (PP), and vasoactive intestinal peptide (VIP) were determined at rest and before and after each exercise session. The duration, amplitude, and frequency of esophageal contractions declined with increasing exercise intensity, and the differences were significant (P≤0.05) for all three variables at 90% $\dot V$ O₂ max. The number of gastroesophageal reflux episodes and the duration of esophageal acid exposure were significantly (P≤0.05) increased during exercise at 90% $\dot V$ O₂ max. Plasma regulatory peptide concentrations showed no significant changes between rest and the various exercise sessions. Thus, exercise has profound effects on esophageal contractions and gastroesophageal reflux, which are intensity dependent. These effects were not mediated by the hormones measured. The results were similar to those observed in highly trained athletes, suggesting that the effects of exercise on esophageal function are similar in trained and nontrained subjects performing at similar percentages of $\dot V$ O₂ max, even though the absolute levels of exercise achieved in each group are different.