We sought to evaluate the effects of exercise and aspirin on gastroduodenal and intestinal permeability. Seven volunteers (age = 29 ± 3 yr;˙VO2max = 56.8 ± 4.1 ml·kg-1·min-1) rested or performed treadmill exercise (60 min at ≈68% ˙VO2max), with or without aspirin ingestion. Placebo (glucose) or aspirin (1.3 g) was taken the night before and prior to rest or exercise (total 2.6 g). A permeability test solution (≈ 1300 mOsm·kg-1), containing 10 g lactulose (L), 5 g mannitol(M), and 10 g sucrose (S), was ingested prior to rest or exercise. Urinary excretion rates (6·h-1), expressed as a percentage of ingested dose, were used to quantify intestinal (L/M ratio) or gastroduodenal (S) permeability. Ingestion of aspirin before running increased (P < 0.05) intestinal permeability compared to placebo + running and placebo + rest, but not compared to aspirin + rest; mean (±SE) values for the L/M ratio were 0.248 ± 0.046, 0.029 ± 0.012, 0.012 ± 0.004, and 0.104 ± 0.057, respectively. Gastroduodenal permeability following aspirin + running (3.25 ± 1.21%) was also elevated (P < 0.05) compared to placebo + running (0.43 ± 0.15%) and placebo + rest(0.24 ± 0.11%), but not compared to aspirin + rest (0.66 ± 0.27%). Neither running nor aspirin ingestion was associated with gastrointestinal (GI) complaints. Thus, GI permeability while running can be markedly elevated by aspirin ingestion.
Department of Exercise Science, University of Iowa, Iowa City, IA 52242-1111
Received for publication July 1995.
Accepted for publication December 1995.
We thank Nicholas E. Walker and Kelly Martens for their generous help in conducting these experiments, and our subjects for their dedicated participation.
This investigation was supported by a grant from the Gatorade Sport Science Institute.
A preliminary version of this work was presented at the 1995 ACSM Annual Meeting in Minneapolis, MN (Med. Sci. Sports Exerc. 27(5 Suppl.):S213, 1995).