Gastric emptying during walking and running: effects of varied exercise intensity

Abstract

Gastric emptying is increased during running (50%-70% maximal aerobic uptake, {Mathematical expression} as compared to rest. Whether this increase varies as a function of mode (i. e. walking vs running) and intensity of treadmill exercise is unknown. To examine the gastric emptying characteristics of water during treadmill exercise performed over a wide range of intensities relative to resting conditions, 10 men ingested 400 ml of water prior to each of six 15 min exercise bouts or 15 min of seated rest. Three bouts of walking exercise (1.57 m · s-1) were performed at increasing grades eliciting ∼28%, 41% or 56% of {Mathematical expression}. On a seperate day, three bouts of running (2.68 ms-1) exercise were performed at grades eliciting ∼57%, 65% or 75% of {Mathematical expression}. Gastric emptying was increased during treadmill exercise at all intensities excluding 75% {Mathematical expression} as compared to rest. Gastric emptying was similar for all intensities during walking and at 57% and 65% {Mathematical expression} during running. However, running at 74% {Mathematical expression} decreased the volume of original drink emptied as compared to all lower exercise intensities. Stomach secretions were markedly less during running as compared to walking and rest. These data demonstrate that gastric emptying is similarly increased during both moderate intensity (∼8%-65% {Mathematical expression}) walking or running exercise as compared to resting conditions. However, gastric emptying decreases during high intensity exercise. Increases in gastric emptying during moderate intensity treadmill exercise may be related to increases in intragastric pressure brought about by contractile activity of the abdominal muscles. © 1989 Springer-Verlag.