Strenuous exercise increases gastrointestinal damage, but the dose-response relationship is yet to be elucidated. It is also commonly believed that running causes greater gastrointestinal damage than cycling. Two randomised, cross-over studies aimed to 1) quantify gastrointestinal damage with increasing exercise intensity, and 2) determine if running was associated with greater gastrointestinal damage than cycling. Following a V̇O2max test, participants completed three cycling trials at different intensities (60min at 40%, 60% and 80% V̇O2max; n=10 (5 female, 5 male)) (INTENSITY), or one running and one cycling trial (45min at 70% V̇O2max; n=11 (3 female, 8 male)) (MODE). Venous blood samples were collected pre- and post- exercise to measure gastrointestinal damage via intestinal fatty acid binding protein (I-FABP). In INTENSITY, I-FABP magnitude of change was greater at 80% V̇O2max than 40% V̇O2max (p<0.01). In MODE, I-FABP magnitude of change was greater with cycling (mean (SD)) (84.7 (133.2)% d=1.07) compared to running (19.3 (33.1)%, d=0.65) with a moderate effect (d=0.68, p=0.024). RPE and HR were higher during cycling (RPE p<0.0001; HR p<0.0001) but rectal temperature was not different between modes (p=0.94). While gastrointestinal damage increases with increasing exercise intensity, running was not associated with greater gastrointestinal damage than cycling. Novelty Bullets: •A fraction of the anaerobic threshold, rather than a fraction of V̇O2max, may be more predictive of intensity that results in exercise induced gastrointestinal damage •The mode of exercise may not be as important as intensity for inducing gastrointestinal damage •Improving anaerobic threshold may reduce susceptibility to gastrointestinal damage when exercising at high intensities

2022-Exercise is associated with a reduction in splanchnic blood flow that leads to the disruption of intestinal epithelium integrity, contributing to exercise-induced gastrointestinal syndrome. Strategies that promote intestinal blood flow during exercise may reduce intestinal damage, which may be advantageous for subsequent recovery and performance. This study aimed to explore if exercise-associated intestinal damage was influenced by wearing compression garments, which may improve central blood flow. Subjects were randomly allocated to wear compression socks (n 5 23) or no compression socks (control, n 5 23) during a marathon race. Blood samples were collected 24 hours before and immediately after marathon and analyzed for intestinal fatty acid-binding protein (I-FABP) concentration as a marker of intestinal damage. The magnitude of increase in postmarathon plasma I-FABP concentration was significantly greater in control group (107%; 95% confidence interval [CI], 72-428%) when compared with runners wearing compression socks (38%; 95% CI, 20-120%; p 5 0.046; d 5 0.59). Wearing compression socks during a marathon run reduced exercise-associated intestinal damage. Compression socks may prove an effective strategy to minimize the intestinal damage component of exercise-induced gastrointestinal syndrome.

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) are hormones produced by the adrenal cortex that decline in concentration with age. Decreased DHEA levels are associated with age-related disease and oxidative stress but might be increased in younger adults by exercise. Studies are presented assessing the response of DHEA and DHEAS to varied-intensity exercise in older age. DHEA increased significantly in young adults (14.5 +/- 6.1 ng/ml rising to 21.1 +/- 7.5 ng/ml; p < .01), whereas DHEAS decreased significantly (2.56 +/- 1.11 microg/ml falling to 1.90 +/- 0.8 microg/ml; p < .05), after submaximal exercise. DHEA and DHEAS levels were significantly lower in older adults than in younger adults (p < .01), and there was no observed response of either hormone to exercise in older adults. Lipoprotein protein carbonylation is presented as a measure of oxidative status and significantly decreased in younger adults postexercise. Participants with higher DHEA postexercise had lower LDL protein carbonyl concentrations (Pearson's coefficient -.409, p < .05).

Background As more people are surviving stroke, there is a growing need for services and programs that support the long-term needs of people living with the effects of stroke. Exercise has many benefits; however, most people with stroke do not have access to specialized exercise programs that meet their needs in their communities. To catalyze the implementation of these programs, our team developed the Stroke Recovery in Motion Implementation Planner, an evidence-informed implementation guide for teams planning a community-based exercise program for people with stroke. Objective This study aimed to conduct a user evaluation to elicit user perceptions of the usefulness and acceptability of the Planner to inform revisions. Methods This mixed methods study used a concurrent triangulation design. We used purposive sampling to enroll a diverse sample of end users (program managers and coordinators, rehabilitation health partners, and fitness professionals) from three main groups: those who are currently planning a program, those who intend to plan a program in the future, and those who had previously planned a program. Participants reviewed the Planner and completed a questionnaire and interviews to identify positive features, areas of improvement, value, and feasibility. We used descriptive statistics for quantitative data and content analysis for qualitative data. We triangulated the data sources to identify Planner modifications. Results A total of 39 people participated in this study. Overall, the feedback was positive, highlighting the value of the Planner’s comprehensiveness, tools and templates, and real-world examples. The identified areas for improvement included clarifying the need for specific steps, refining navigation, and creating more action-oriented content. Most participants reported an increase in knowledge and confidence after reading the Planner and reported that using the resource would improve their planning approach. Conclusions We used a rigorous and user-centered process to develop and evaluate the Planner. End users indicated that it is a valuable resource and identified specific changes for improvement. The Planner was subsequently updated and is now publicly available for community planning teams to use in the planning and delivery of evidence-informed, sustainable, community-based exercise programs for people with stroke.

Ultra-endurance athletes accumulate an energy deficit throughout their events and those competing in self-sufficient multi-stage races are particularly vulnerable due to load carriage considerations. Whilst urinary ketones have previously been noted in ultra-endurance exercise and attributed to insufficient carbohydrate (CHO) availability, not all studies have reported concomitant CHO intake. Our aim was to determine changes in blood glucose and βhydroxybutyrate concentrations over five days (240 km) of a self-sufficient multi-stage ultramarathon in combination with quantification of energy and macronutrient intakes, estimated energy expenditure and evaluation of energy balance. Thirteen runners (8 male, 5 female, mean age 40 ± 8 years) participated in the study. Glucose and β-hydroxybutyrate were measured every day immediately post-running, and food diaries completed daily. CHO intakes of 301 ± 106 g•day -1 (4.3 ± 1.8 g•kg -1 •day -1 ) were not sufficient to avoid ketosis (5-day mean βhydroxybutyrate: 1.1 ± 0.6 mmol.L -1 ). Furthermore, ketosis was not attenuated even when CHO intake was high (9 g•kg -1 •day -1 ). This suggests that competing in a state of ketosis may be 44 inevitable during multi-stage events where load reduction is prioritised over energy provisions.Attenuating negative impacts associated with such a metabolic shift in athletes unaccustomed to CHO and energy restriction requires further exploration.