Objective: To assess the prevalence, risk factors and timing of gastrointestinal (GI) complaints in a large group of runners competing in a long-distance run. GI symptoms indicating GI ischaemia were of specific interest.
Material and methods: A questionnaire was sent by e-mail to 2076 athletes who had competed in a recreational run and 1281 (62% response rate) were returned. Reported GI complaints were related to variables such as age, gender, distance, fluid and food ingestion and running experience. For statistical analyses, chi(2) tests and logistic regression analyses were used.
Results: The run was completed by 98% of the runners. Three athletes dropped out because of GI complaints, 45% had at least one GI complaint during running, while 11% of the runners suffered from serious GI complaints during the run, the last mentioned being significantly related to runners who were not familiar with fluid ingestion, those of younger age, female gender and those who did not complete the run. Of the runners, 2.7% had complaints during the first 24 h after the run. This was significantly related to female gender and GI complaints during the run.
Conclusions: The prevalence of GI complaints during and after running was low compared with that reported in other studies, which is partly due to the definition of "symptomatic" used in our study. The risk factors associated with becoming symptomatic were identical to those in other studies. The relationship between complaints during the run and the type of complaints afterwards suggests a role of GI ischaemia in the pathophysiology of running-induced GI symptoms.