A comprehensive approach to address exercise-associated gastrointestinal syndrome: Evaluation and treatment strategies

Research methods and procedures There are four main quantitative phases of this project: Trial phase 1: (about 1 weeks after recruitment) Clinical assessment of the athlete (n=12) Conducted by the lead researcher via home office using Zoom Clinical assessment of the athlete (n=12) will include specific details about their GIS during exercise (i.e., type, severity, onset, timing, modality, environmental conditions, pre- and during exercise feeding and drinking habits). Trial phase 2: At least 2 weeks after phase 1. A laboratory-controlled simulated gastrointestinal assessment during exercise (GastroAxEx). (This is the part to be conducted at Toi Ohomai Aquatic centre lab) Conducted by the lead researcher plus lab assistant at Toi Ohomai. The lead researcher is trained and experienced in exercise physiology laboratory techniques and is familiar with all of the lab assessment methods to be conducted. The lab assistant intended to be utilised is a PhD sports and recreation student who is routinely used by the Sport and Recreation department; they are familiar with all exercise physiology and standard operating procedures used in the lab. The trial day will be within the Aquatic centre opening hours to ensure additional support is required should any emergency arise. A laboratory-controlled simulated gastrointestinal assessment during exercise (GastroAxEx). Total participants for the study, n = 12 n = 1 participant for each trial (test) day Trial day procedures • Participants will be asked to replicate and record their typical event preparation (i.e., dietary, exercise, and sleep habits) 48-h leading into the GastroAxEx; this will include an exercise taper (no strenuous exercise 48-h before testing) and their nutritional intake leading into (i.e., 48-h prior) and during the competition (i.e., race nutrition). • Participants will report to the laboratory 1-h before exercise commencement, after consuming their typical pre-event meal or snack 2-h beforehand. A dietary log (2-days) will be used to determine their nutritional intake, as per previously established dietary intake assessment and analysis procedures (Costa et al., 2013a,b). • Participants will be asked to void their bladder and bowel before nude body mass measurement (behind a screened private area), provide a breath sample into a 250 mL breath collection bag (Wagner Analysen Technick, Bremen, Germany), and complete a modified visual analogue scale (mVAS) GIS assessment tool (Gaskell et al., 2019), as a baseline measure. • Participants will then complete their individual tailored GastroAxEx. To ensure adequate exercise stress is applied, participants will run on a motorized treadmill for at least 3-h running at a self-selected intensity/ speed in thermoneutral conditions (22-23 °C). The exercise stress can be modified to simulate each athlete’s running event, e.g., if participants only run 4 or 5-hr events only, then this length of running will be replicated, or if they always increase their pace in the last 15 mins of an event, then the speed will be increased accordingly. • Participants are to be instructed to consume their typical competition food and fluid intake (i.e., race nutrition) along the exercise protocol. During exercise food and fluid intake was recorded in real-time. Water will be available ad libitum throughout exercise, and the volume recorded. • Capillary blood glucose, GIS and feeding tolerance, heart rate (HR), rating of perceived exertion (RPE), and thermal comfort rating (TCR) will be measured every 15 min during exercise. • Breath-by-breath indirect calorimetry (Cortex MetaLyzer 3B, Leipzig, Germany) will be recorded every 20 mins for 5 mins during exercise and in the last 5 mins of exercise. • Tympanic temperature (TTy) nude body mass, and GIS were recorded immediately post-exercise. • Participants will remain seated during the recovery period and can consume water ad libitum (which will be recorded). • GIS will be recorded every 15 min during the 3-h post-exercise period. • Participants will be provided with a standard meal 2-h post-exercise in accordance with ethical procedures. • Breath samples (20 ml) were analysed in duplicate (CV: 3.0%) for hydrogen (H2) and (CH4) content using a gas-sensitive analyser (Breathtracker Digital Microlyzer, Quintron, Milwaukee, Wisconsin, United States). Monash University will supply the breath sample bags and equipment. The samples will be shipped to Australia for testing. This process will be fully investigated, as it might be possible to hire an analyser in New Zealand. Trial phase 3: (approximately 1 - 2 weeks after trial phase 2, participants will be informed of the interventions to trial over a 4-6 week period). Therapeutic intervention phase Conducted by lead researcher via home office using Zoom Please note: The lead researcher is a New Zealand registered dietitian and advanced accredited Dietitian, capable and experienced with the following dietary and non-dietary interventions. Based on the outcomes of the GastroAxEx from Phase 2, an individualised therapeutic intervention phase will be developed consisting of the following aims: Modified pre-exercise food and fluid, gastrointestinal load and/or burden; Maintain gastrointestinal patency during exertional stress; and Ameliorate physiological strain to exercise stress (e.g., thermal strain and euhydration maintenance). All intervention procedures will be practised in training and/or less important event/s, prior to using the interventions in targeted event/s. Primary interventions for training to practice and then continue to implement for events if successful, may include the following 1. Gut-training protocol in training (i.e., participants will practice consuming up to 90g carbohydrates and 300-600mls of water, during exercise over a 2-week period. Exercise will be at least 1 hour long to enable the gut to adapt to digesting both carbohydrates and water during exercise). The aim during events is up to 90g carbs hourly during exercise and 600 mls of water – this is individualized for each participant. 2. Exogenous fuel provision within tolerance in training (if participants consume < 30 g of carbohydrate during endurance exercise, they will be encouraged to practice with higher amounts of up to 90 g hourly during exercise over a 2-week period. Exercise will be at least 1 hour long to enable the gut to adapt to digesting both carbohydrates) 3. Hydration provision within tolerance in training (if participants consume < 300 mL water hourly during endurance exercise they will be encouraged to practice with higher amounts of up to 600 mL hourly during exercise over a 2-week period. Exercise will be at least 1 hour long to enable the gut to adapt to higher fluid volumes) 4. Thermoregulation targeted and heat acclimation/acclimatization strategies (if participants plan to race in a warm (30 °C) or hot (35°C) environment, they will be encouraged to start training in warmer temperatures i.e., indoors on treadmills in controlled environments, or acclimate to the place they intend to race in for at least 2 weeks prior to an event). 5. Pre- and/or per-internal and/or external cooling strategies (if participants appear to overheat during exercise as seen by an increase in typmanic temperature, they will be encouraged to consume cool (<7°C) beverages or ice slushies or wear ice vests during training to reduce body temperature for at least 2 weeks during training). 6. Pre-exercise dietary management (depending on pre-exercise food diary analysis, participants may encouraged to reduce dietary fibre, fat, or protein to be in line with sports nutrition recommendations before endurance exercise, this may include both pre-training and pre-event meals). 7. Pharmacotherapy application (i.e., ondansetron with medical collaboration and prescription if participants suffer from nausea during exercise – usually prescribed to take during events prior to the usual onset of nausea but depending on the individual this maybe warranted for longer training sessions, and NSAID avoidance if participants take NSAID prophylactically in races). 8. Taking into account the biological sex of the athlete (Females will require calendar-based counting and use a menstrual tracking app (i.e., Clue) to track their menstrual cycles with the aim of running an event within the early follicular phase of their cycle. This may take up to 4 weeks to establish the correct menstrual phase to run an event in). Primary intervention for the two days before an event will include the following 10. 48-h HCLF dietary control [i.e., low fermentable oligo- di- mono- saccharide and polyols (FODMAP)], prescribed by the lead researcher (participants will be provided with several interventions as above to practice during training, and then they will be advised on how to consume a high carbohydrate low FODMAP diet before an event. Dietary guidelines and a suggested meal plan will be provided). Trial phase 4: (After trial phase 3, participants will be trialing interventions for at least 4 - 6 weeks. This may involve 1 - 2 follow-ups by the lead researcher to check with the participants how the interventions are progressing. This will take 4 - 6 weeks). Monitoring and readjustment of intervention Conducted by lead researcher (Rachel Scrivin) via home office using Zoom To monitor and check the following; 1. Checking the athlete was healthy (i.e., free from gastrointestinal diseases and/ or disorders unrelated to exercise prior to the intervention), 2. Adherence to the dietary intervention, 3. Gut-training compliance, 4. Food and fluid intake during exercise tolerance, 5. Thermal strain targeted strategy tolerance and compliance, 6. Menstrual status where applicable (i.e., the female athlete). In addition, measuring and recording GIS during exercise, physiological variables, and environmental conditions in training and/or competition where possible, checking other potential triggers (e.g., nutritional supplementation and anti-inflammatory medication), and assessing whether further gastrointestinal assessment at rest and during exercise is warranted (i.e., medical procedures for gastrointestinal disease/disorder diagnosis, gut microbiota composition, luminal pathogenic assessment (e.g., fungal, bacterial, parasitic, and/or allergen), specific food allergen or intolerance). Participants and how they are recruited Participants (n = 12) will be recruited through researcher contacts (i.e., Dietitians NZ social media pages, Sports Dietitians Special interest group contacts, and various local endurance running pages such as Papamoa running buddies Facebook page). Participants will be required to attend an initial 1-hr online Zoom session for clinical assessment to determine study inclusion, followed by a subsequent 7-hr GastroAxEx trial day and at least 2 x 1-hr Zoom follow-up sessions.