Frequency of Chronic Gastrointestinal Distress in Runners: Validity and Reliability of a Retrospective Questionnaire

Gastrointestinal (GI) symptoms may affect up to 90% of competitors during endurance races. Studies have typically assessed GI symptoms retrospectively or only over an acute timeframe, and information on the validity and reliability of the questionnaires employed is lacking. This investigation aimed to estimate the frequency of GI distress experienced by runners over 30 days and to establish the validity and reliability of a retrospective GI symptom questionnaire. Runners (70 men, 75 women) recorded GI symptoms with a prospective journal for 30 days. Retrospective GI symptom data were then collected after the 30-day period on two occasions within one week. GI symptoms were rated on a 0-10 scale. Descriptive statistics for GI symptoms are reported as medians (interquartile ranges) because of nonnormal distributions. Men and women experienced at least one GI symptom on 84.0% (59.8-95.1%) and 78.3% (50.0-95.2%) of runs, respectively. Moderate-to-severe GI symptoms (score of ≥5) were experienced on 13.8% (6.7-37.3%) and 21.7% (5.3-41.2%) of runs for men and women. Spearman's rho correlations between journal ratings and retrospective questionnaire ratings ranged from 0.47 to 0.82 (all p < .001), although they were highest when journal ratings were quantified as mean 30-day values (all rho ≥ 0.59). Reliability of the retrospective questionnaire ratings was high (rho = 0.78-0.92; p < .001). In comparison with tracking GI symptoms with a daily journal, retrospective questionnaires seem to offer a convenient and reasonably valid and reliable method of quantifying GI symptoms over 30 days.