EFFECT OF GRADED-EXERCISE ON ESOPHAGEAL MOTILITY AND GASTROESOPHAGEALREFLUX IN NONTRAINED SUBJECTS

The effects of graded exercise on esophageal motility and gastroesopha geal reflux were evaluated in nine nontrained subjects, using a cathet er with three strain-gauge transducers connected to a solid-state data logger and an ambulatory intraesophageal pH monitor. Subjects exercise d on a stationary bike at 45%, 60%, 75%, and 90% of peak O-2 uptake (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 s tudy. Plasma concentrations of gastrin, motilin, glucagon, pancreatic polypeptide (PP) and vasoactive intestinal peptide (VIP) were determin ed at rest and before and after each exercise session. The duration, a mplitude, and frequency of esophageal contractions declined with incre asing exercise intensity, and the differences were significant (P less than or equal to 0.05) for all three variables at 90% VO2 max. The nu mber of gastroesophageal reflux episodes and the duration of esophagea l acid exposure were significantly (P less than or equal to 0.05) incr eased during exercise at 90% VO2 max. Plasma regulatory peptide concen trations showed no significant changes between rest and the various ex ercise sessions. Thus, exercise has profound effects on esophageal con tractions 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 tra ined and nontrained subjects performing at similar percentages of VO2 max, even though the absolute levels of exercise achieved in each grou p are different.