Numerous causes of exercise-related gastrointestinal (GI) distress exist but scarce research has evaluated potential psychological causes. Runners (74 men, 76 women) prospectively recorded running duration, intensity (Rating of Perceived Exertion [RPE]), and GI symptoms for 30 days. Six GI symptoms were rated on a 0-10 scale. The percentage of runs over 30 days that participants reported at least one upper, lower, or any GI symptom ≥3 was calculated. After 30 days, participants completed a questionnaire on GI distress triggers (demographics, anthropometrics, experience, analgesic use, antibiotic use, probiotic consumption, fluid/food intake, stress, anxiety). Stress and anxiety were measured via the Perceived Stress Scale (PSS) and Beck Anxiety Inventory (BAI). The median percentage of runs that participants experienced at least one GI symptom ≥3 was 45.6% (interquartile range [IQR], 16.6-67.3%). Age and running experience negatively correlated with GI distress occurrence (rho = -0.17 to -0.34; p < 0.05). Run RPE, probiotic food consumption, PSS scores, and BAI scores positively correlated with GI distress occurrence (rho = 0.18 to 0.36; p < 0.05). Associations between GI distress, stress and anxiety remained significant after adjustment for covariates, except for lower GI symptoms. This study suggests that stress and anxiety contribute to running-related GI distress.
Keywords: Anxiety; endurance exercise; gastrointestinal distress; sport nutrition; stress.