Effect of exercise on gastroduodenal functions in untrained dogs

Eight dogs were used to study the effect of 2 h submaximal (60-70% of maximal heart rate) exercise on gastric secretion and gastroduodenal motor function in fasted and fed states. Fasting gastric acid and pepsin secretion were not affected by exercise. Postprandial gastric acid secretion was significantly depressed (p < 0.05) during the second hour of exercise. Postprandial pepsin secretion was significantly decreased in both resting and exercised states. Gastric emptying of a liquid meal (protein 23.5%, fat 3.5%, carbohydrate 66.5% [w/w], 390kcal) was significantly delayed by exercise (p < 0.05). The migrating motor complex (MMC) was not observed during exercise, however, upon cessation of exercise, MMCs appeared at an expected 214 +/- 14 min after the pre-exercise MMC. Exercise did not affect the mean motor activity of the stomach but significantly increased the mean frequency (p < 0.05) and amplitude (p < 0.01) of the contractions in the duodenum, in the fasted and fed states, respectively. In conclusion, exercise lasting more than 1 h significantly depressed postprandial gastric secretion and significantly delayed gastric emptying (p < 0.05). Duodenal motor activity was significantly increased (p < 0.05 and p < 0.01) by exercise in both the fasted and fed states.