Exercise-Induced Gastrointestinal Symptoms in Endurance Sports: A Review of Pathophysiology, Symptoms, and Nutritional Management

Strenuous exercise can be associated with “Exercise Induced Gastrointestinal Syndrome” (Ex-GIS), a clinical condition characterized by a series of gastrointestinal (GI) disturbances that may impact the physical and psychological performance of athletes. The pathophysiology comprises multi-factorial interactions between the GI tract and the circulatory, immune, enteric, and central nervous systems. There is considerable evidence for increases in the indices of intestinal damage, permeability, and endotoxemia associated with impaired gastric emptying, slowing of small intestinal transit, and malabsorption of nutrients. Heat stress and racing mode seem to exacerbate these GI disturbances. GI symptomatology that derives from strenuous exercise is similar to that of IBS and other GI functional disorders defined in the Rome IV Criteria. To manage Ex-GIS, the exercise modality, state of dehydration, environmental temperature, concomitant therapies, and self-managed diet should be evaluated, and if risk elements are present, an attempt should be made to modify them. Multiple strategies can be successively adopted to manage Ex-GIS. Nutritional and behavioral interventions appear to be the principal ones to avoid symptoms during the exercise. The aim of this review will be to explore the pathophysiology, clinical aspect, and current literature on behavioral and nutritional strategies to manage Ex-GIS, regarding a gluten-free diet and low-fermentable oligo-, di-, and mono-saccharides and polyols (FODMAP) diet.