“Exercise-induced gastrointestinal syndrome” refers to disturbances of gastrointestinal integrity and function that are common features of strenuous exercise.

Dr Costa and colleagues from Australia systematically reviewed the literature to establish the impact of acute exercise on markers of gastrointestinal integrity, and function in healthy populations and those with chronic gastrointestinal conditions.

The team searched the literature using 5 databases to review publications that focused on the impact of acute exercise on markers of gastrointestinal injury, permeability, endotoxaemia, motility and malabsorption in healthy populations and populations with gastrointestinal diseases/disorders.

As exercise intensity and duration increases, there is considerable evidence for increases in indices of intestinal injury, permeability and endotoxemia, together with impairment of gastric emptying, slowing of small intestinal transit and malabsorption. 

The researchers observe that the addition of heat stress and running mode appears to exacerbate these markers of gastrointestinal disturbance. 

Exercise stress of 2 hours or more at 60% VO2max appears to be the threshold whereby significant gastrointestinal perturbations manifest, irrespective of fitness status. 

The team observed that gastrointestinal symptoms, referable to upper- and lower-gastrointestinal tract, are common and a limiting factor in prolonged strenuous exercise. 

While there is evidence for health benefits of moderate exercise in patients with inflammatory bowel disease or functional gastrointestinal disorders, the safety of more strenuous exercise has not been established.

Dr Costa's team concludes, "Strenuous exercise has a major reversible impact on gastrointestinal integrity and function of healthy populations."

"The safety and health implications of prolonged strenuous exercise in patients with chronic gastrointestinal diseases/disorders, while hypothetically worrying, has not been elucidated and requires further investigation."