Although functional disorders of GI tract including abdominal pain, diarrhea and hemorrhagic stool occur after strenuous exercise, their mechanisms remain unclear. We examined the effect of strenuous exercise on intestinal mucosal immunity. Male C57BL/6j mice were given treadmill exercise (8~28 m/min, 100 min) and plasma levels of cortisol and TGF-β were analyzed. We found that plasma cortisol rapidly increased and maintained its high levels (~12 hr) while TGF-β increased 6 hr after the exercise. Mucosal IgA in the small intestine and colon increased markedly after the exercise. Furthermore, apoptotic cells were found to increase in the colon but not in the small intestine. These results suggest that strenuous exercise causes enhanced immune reactions in intestinal mucosa thereby induces apoptosis of colonal cells. These changes in mucosal immunity may underlie the functional disorders of the GI tract after strenuous exercise.

DESCENTE SPORTS SCIENCE Vol.25/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE