Systematic review: exercise‐induced gastrointestinal syndrome—implications for health and intestinal disease

Abstract

Summary Background “Exercise‐induced gastrointestinal syndrome” refers to disturbances of gastrointestinal integrity and function that are common features of strenuous exercise. Aim To systematically review 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. Methods Search literature using five databases (PubMed, EBSCO, Web of Science, SPORTSdiscus, and Ovid Medline) 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. Results As exercise intensity and duration increases, there is considerable evidence for increases in indices of intestinal injury, permeability and endotoxaemia, together with impairment of gastric emptying, slowing of small intestinal transit and malabsorption. The addition of heat stress and running mode appears to exacerbate these markers of gastrointestinal disturbance. Exercise stress of ≥2 hours at 60% VO2max appears to be the threshold whereby significant gastrointestinal perturbations manifest, irrespective of fitness status. 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. Conclusions 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.

Reliability of gastrointestinal barrier integrity and microbial translocation biomarkers at rest and following exertional heat stress

“…Exertional heat stress is one stimulus that adversely disrupts GI barrier integrity, and in a linear manner to the severity of splanchnic hypoperfusion (van Wijck et al, ) and core body temperature (Pires et al, ). In severe cases, luminal microbial products are capable of transversion into the systemic circulation, a response now considered to underlie multiple common athletic health conditions (Costa, Snipe, Kitic, & Gibson, ). Specifically, the most concerning of these health conditions include exercise‐induced anaphylaxis (Christensen et al, ) and exertional heatstroke (Lim, ).…”

“…GI MT can be assessed in vivo through several indirect biomarkers considered to be indicative of systemic microbial exposure (Wells et al, ). Endotoxin, a form of lipopolysaccharide located on the outer membrane of gram‐negative bacteria, has traditionally been utilized for this purpose (Costa et al, ). However, the search for improved GI MT biomarkers is ongoing, given endotoxin analysis is susceptible to both false‐positive (e.g., from exogenous contamination) and false‐negative (e.g., from rapid hepatic clearance) results (Dullah & Ongkudon, ).…”

Gastrointestinal symptoms in elite athletes: time to recognise the problem?

“…However, there has been less research in examining the prevalence of such symptoms in other sports, particularly at elite level. This is surprising given that many of the factors associated with GI damage and symptoms are commonly seen in sport, such as use of non-steroidal anti-inflammatories, GI ischaemia during high-intensity exercise, a wide variety of dietary habits, use of buffering supplements such as sodium bicarbonate and mechanical effects such as bouncing of organs 4. Furthermore, GI illnesses are often one of the most commonly diagnosed during major international sporting events 5…”

Acute exercise inhibits gastric emptying of liquids in rats: influence of the NO-cGMP pathway

“…Slower emptying with exercise at higher intensities and longer duration has been observed; however, the impact of acute exercise is not clear. Considering that physical activity promotes a potent sympathetic impulse, it is believed that sympathetic activation may delay gastric emptying in response to stress (39). …”

“…Physical exercise is often accompanied by the ingestion of beverages, and their composition, volume, and energy density can alter the GE rate, which could influence several factors, such as exercise intensity and training conditions (39). …”