title: Effect of exercise on mouth-to-cecum transit in trained athletes: a case against the role of runners' abdominal bouncing.
abstract: The role of exercise on the gastrointestinal motor function and in particular on transit time is a matter of hard debate. Numerous studies in the past have failed to demonstrate a consistent effect of short term exercise on transit time in untrained subjects and trained athletes. It has been, however, suggested that running, with its constant jostling of the abdomen, may have a different effect than exercise performed in a stationary setting. To examine the effect of running on gastrointestinal transit time, 8 healthy male trained runners ingested a lactulose meal and assigned to rest or exercise on separate days. Exercise consisted of running 9.6 km in an hour, while exhaled gas was sampled every 10 minutes for volume, minute ventilation and hydrogen concentration. The mean O2 consumption was 36.8 ml/min/kg during exercise session and 4.7 ml/min/kg during rest period. Post lactulose rise in hydrogen concentration occurred at a mean of 85 +/- 25.1 and 84 +/- 18.1 minutes for resting and exercise sessions respectively (p = 0.732). On the basis of the present data we conclude that (1) mouth-to-cecum transit time is not affected by short term intense exercise in trained athletes; (2) that bouncing of the abdominal content in case of running probably does not change the transit time; and finally, (3) the impact of moderate to intense short term exercise on the mouth-to-cecum transit is not influenced by the subject's fitness state.
authors.affiliation: Department of Medicine, University of California, Irvine, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Kayaleh
authors.forename: H
authors.initials: H
authors.lastname: Meshkinpour
authors.forename: A
authors.initials: A
authors.lastname: Avinashi
authors.forename: A
authors.initials: A
authors.lastname: Tamadon
mesh_terms: D000005:Abdomen / Q000502:physiology; D000328:Adult; D000704:Analysis of Variance; D002245:Carbon Dioxide / Q000032:analysis; D002432:Cecum / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005765:Gastrointestinal Agents / Q000378:metabolism; D005769:Gastrointestinal Motility / Q000502:physiology; D005772:Gastrointestinal Transit / Q000502:physiology*; D006801:Humans; D006859:Hydrogen / Q000032:analysis; D007792:Lactulose / Q000378:metabolism; D008297:Male; D009055:Mouth / Q000502:physiology; D010100:Oxygen / Q000032:analysis; D010101:Oxygen Consumption / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology; D012119:Respiration / Q000502:physiology; D012146:Rest / Q000502:physiology; D012420:Running / Q000502:physiology*; D013147:Spirometry; D013997:Time Factors
chemical_list: D005765:Gastrointestinal Agents; D002245:Carbon Dioxide; D007792:Lactulose; D006859:Hydrogen; D010100:Oxygen