Table 4.

Practical recommendations for the management of exercise-induced gastrointestinal syndrome, and associated gastrointestinal symptoms, as a result of exertional-heat stress.

Essential: - Undertake a gastrointestinal assessment (e.g. gut challenge protocols) during exertional-heat stress, for identification of primary causal mechanism and secondary gastrointestinal integrity and functional outcomes [4,23,93]. - Undertake a gastrointestinal assessment during exertional-heat stress in a training or competition mirrored simulation, to establish individual tolerance to fuel and fluid types, forms, and concentrations [23,29,93]. - Identify and manage extrinsic and intrinsic exacerbating factors [4].

Strategies to consider: - Begin exercising in hot ambient conditions euhydrated, and maintain euhydration throughout (within individual tolerance) using ad libitum fluid intake behaviors [59,106]. - Avoid overconsuming fluids, and scenarios of exercise-associated hyponatremia [29,103,104,106]. - Carbohydrate before and frequently throughout exertional-heat stress [118]. - Undertake a gastrointestinal assessment during exertional-heat stress to establish exercise-associated nutrient malabsorption, especially of high FODMAP sources (e.g., fructose, lactose, sorbitol, mannitol, and lupin flour) that are common ingredients found in sports nutrition products, and adapt pre- and during-exercise nutrition accordingly [23,29,143]. - Trial and practice competition nutrition in training sessions, including specific food and fluid quality and quantity [23]. - Avoid NSAID medication in the day leading up to, immediately before, and during exertional-heat stress [39]. - Gut training protocols [23,29]. - Short-term low FODMAP diet, with or without low residue, after assessment to establish tolerance [4,93,143]. - Internal and external cooling strategies to limit thermoregulatory strain; such as pre- and per-cooling using cool fluids, and cool water bathing, showers, or vests [60]. - Undertake appropriate heat acclimation/acclimitization protocols prior to competition in hot ambient conditions. Consider specific exercise mode, intensity, duration, and Tamb per exercise bout; and also, frequency of exertional-heat exposures and timescale between exposures [69].

Unlikely to be of benefit (unclear outcomes or requiring further substantiation): - Gluten free dietary interventions in athletes without diagnosed coeliac disease [136]. - Nutritional supplementation interventions (e.g. antioxidants, specific amino-acids, bovine colostrum, and curcumin) (Table 3). - Probiotic supplementation (Table 3). - Exercise or dietary regimes to alter gastrointestinal microbiota bacterial relative abundance, diversity, and (or) functional properties [4].