THE EFFECT OF INTERMITTENT HIGH-INTENSITY RUNNING ON THE RATE OF GASTRIC EMPTYING IN MAN

Abstract

PURPOSE The aim of this study was to examine the effect of variable-intensity shuttle running exercise on the gastric emptying rate of a carbohydrate-free placebo (P) drink and of a 6.4% carbohydrate-electrolyte (CHO) sports drink. METHOD We compared the volume of test drink emptied in 8 healthy males during two 15 min periods of low intensity walking exercise (WE) and during two 15 min periods of a shuttle running test (LIST) that simulates the activity pattern of soccer. Gastric emptying was measured on the four trials using a modification of the double sampling aspiration technique following ingestion of a body mass adjusted volume of the appropriate test drink. On each trial, subjects ingested 420 ± 49 ml (5 ml/kg) of test drink immediately before starting the first 15 min of exercise and 167 ± 18 ml (2 ml/kg) was ingested before the second exercise bout. RESULTS During the initial 15 min of exercise, the volume of P (124 ± 95 ml) and CHO (71 ± 43 ml) drinks emptied was similar for the two LIST trials, but the volume of P (227 ± 85 ml) and CHO (159 ± 63 ml) drinks emptied on the WE trials was greater than for the respective test drinks on the LIST trials (p < 0.05). Similar volumes of test drinks were emptied on all trials (p = 0.20) during the second 15 min of exercise. Over the 30 min of each trial, the exercise intensity of the LIST reduced the volume of the P (211 ± 108 ml) and CHO (208 ± 83 ml) drink emptied from the stomach compared with that on the WE trial for the P (396 ± 74 ml; p < 0.001) and CHO (293 ± 73 ml; p < 0.05) drink respectively. CONCLUSIONS The data demonstrate that the exercise intensity of the LIST is sufficient to slow gastric emptying of both carbohydrate and non-carbohydrate containing drinks compared to low-intensity walking. Dilute carbohydrate-electrolyte drinks are emptied at about the same rate as carbohydrate-free beverages during variable-intensity running.