Effect of moderate intensity exercise on gastric emptying and absorption using pet technique

The purpose of this study was to investigate the effect of moderate intensity exercise on gastric emptying and absorption using positron emission tomography (PET) with oral ¹⁸F-fluoro-deoxy-glucose (¹⁸F-FDG) intake. Seven healthy subjects aged 20-28 years volunteered to participate in this study. Each subject exercised on a bicycle ergometer for 30 minutes at 60% maximal oxygen uptake (Exercise trial). A control trial (without exercise) was also performed by the subjects. Immediately before starting exercise, 300ml of water containing ¹⁸F-FDG was orally administered. ¹⁸F-FDG accumulation in the alimentary tract was measured with 3D PET after the end of exercise. Regions of interest were drawn on visually defined stomach and small intestine. To measure blood glucose, plasma radioactivity, and plasma CCK, blood was sampled 4 times every 10 minutes throughout the exercise. Percent contents of remaining radioactivity in stomach in exercise trial was higher than that in control. Significant change in blood glucose level due to exercise was showed. Plasma CCK level in exercise trial was higher than that in control at the end of exercise. The effect of exercise on %contents of remaining radioactivity in the total alimentary tract or change in plasma radioactivity level was not significant. These findings suggest that cycling exercise for 30 minutes at moderate intensity has a depressive effect on gastric emptying of fluid intake partially influenced by CCK, but no marked effect on absorption of ¹⁸F-FDG from the intestine in normal human subjects.