What is runner's belly?

Runner’s belly or runner’s gut occurs when the digestive system becomes irritated during long-distance running [1]. Running is one of the most strenuous forms of exercise on the gastrointestinal (GI) tract, with some studies indicating that up to 80% of runners experience gastrointestinal symptoms during a run [2]. Symptoms associated with a runner's belly include bloating, stomach pain, gas, vomiting, diarrhea, and nausea. These gastrointestinal (GI) issues often occur in runners who are anxious, nervous and/or younger in age, and are often exacerbated by a higher intensity [3]. 

Causes of runner’s belly include dehydration, high-carbohydrate fluids, lack of blood flow to the gut, pre-existing medical conditions, genetics, and timing and composition of meals before a run. Runner’s belly can be avoided through planning food intake around exercise, staying hydrated, wearing loose clothing, and reducing exercise duration [1,3]. Practicing your pre workout nutrition routine during training is essential for minimizing your risk of runner’s gut during a race.