Influence of physical activity on gastric emptying of liquids in normal human subjects

Liquid gastric emptying has been evaluated in 17 normal human subjects during basal conditions, after mild physical stress at 50% of the maximum predictable heart rate, and after maximal physical stress at 70% maximum heart rate. Each subject exercised on a treadmill for 30 min, its speed and inclination varied in order to obtain the desired heart rate. Immediately after the exercise, 400 ml of mineral water were drunk by each subject. Gastric emptying was evaluated by real-time ultrasonography (11 subjects) and scintigraphy (six subjects) through previously described methods. The results show similar data with both techniques. Gastric emptying of the water, considered either as reduction in gastric measurements at ultrasonography or decay in radioactivity in the region of interest corresponding to the stomach at scintigraphy, follows a linear relationship under basal conditions and during physical stress. Compared with basal conditions, gastric emptying of water after maximal stress was prolonged; after mild stress, gastric emptying of the water was accelerated. These findings may support the common belief that mild physical activity favors the digestive process.