PURPOSE: To investigate the effect on gastric emptying of intermittent exercise at varying intensities such as occurs during a soccer match. METHODS: We compared the emptying rate of a carbohydrate-electrolyte (CE) drink during two 15-min periods of a competitive 5-a-side indoor soccer match separated by 10 min and during two 15-min periods of low-intensity walking exercise. Seven healthy male subjects, all of whom regularly played soccer, completed the study. Exercise intensity on each trial was calculated from heart rate recordings. Subjects ingested 500 mL of the CE drink immediately before starting each exercise period. Before and after completing each 15-min exercise period, the gastric contents were aspirated and the volume recorded. Ambient room temperature ranged from 16-22 degrees C and humidity ranged from 57-72% on both trials. RESULTS: Mean +/- SD heart rate was higher during the Soccer trial than during the Walking trial at all time points. Exercise intensity was calculated to be 54 +/- 23% and 63 +/- 20% VO2max, respectively, for the first and second periods of exercise on the Soccer trial and 13 +/- 9% and 12 +/- 11% VO2max, respectively, for the first and second periods of exercise on the Walking trial. During the first 15-min period of exercise, a greater (median (range)) volume of the CE drink was emptied from the stomach on the Walking trial (247 mL (102-361 mL)) than on the Soccer trial (84 mL (17-230 mL); P = 0.022). In the second exercise period, however, gastric emptying rates were not different (P = 0.16) between the Walking trial (247 mL (104-363 mL)) and Soccer trial (148 mL (17-293 mL)). CONCLUSION: As indicated by heart rate, the overall exercise intensity of an indoor soccer match appears to be moderate. The pattern of activity during a match is intermittent with periods of low level activity punctuated by short bursts of high-intensity sprinting. The present study demonstrates that the intensity of activity during this type of exercise is sufficient to slow gastric emptying.
Leiper, J. B., Prentice, A. S., Wrightson, C., & Maughan, R. J. (2001). Gastric emptying of a carbohydrate-electrolyte drink during a soccer match. Medicine and Science in Sports and Exercise, 33(11), 1932-1938. https://doi.org/10.1097/00005768-200111000-00020