The acute cycling exercise-induced inflammatory response on those with gastrointestinal disorders and healthy controls.

This study investigates the acute exercise-induced inflammatory response for a gastrointestinal group (GI), specifically inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), compared to healthy controls (HC), and further compared moderate-intensity continuous exercise (MICE) with high/low-intensity interval exercise (HIIE) as a randomised crossover protocol. Prior to enrolment into the study, all participants were required to complete the Adult Pre-Exercise Screening System (APSS), a health history questionnaire, and the Depression, Anxiety, and Stress Scales-21 (DASS-21). Participants in the GI group completed an additional disease-specific questionnaire, either Harvey-Bradshaw Index (HBI), the Simple Clinical Colitis Activity Index (SCCAI) or the IBS-Symptom Severity Scale (IBS-SSS) for CD, UC, and IBS, respectively. Following pre-screening, and if satisfying the inclusion criteria, informed consent was obtained, and participants were enrolled into the study. Participants then completed an initial familiarisation and baseline testing session, which included measures of anthropometry, dual-energy x-ray absorptiometry (DEXA) scan, a graded exercise test (GXT), and a fasted blood sample. After a 7 day (d) rest, participants completed two exercise protocols in a randomised, counter-balanced order separated by 7 d. For each testing session a fasted pre-exercise venous blood sample was taken and then immediately (0min), 2h and 24h post exercise. The exercise protocol, described subsequently, was 35 min in duration. The participants remained fasted throughout the exercise protocol and for the 2hr post exercise blood sample. Water was permitted throughout the fast, including throughout the exercise protocol and post-exercise, no food was permitted 8 hours prior to the exercise intervention. Each participant was randomly allocated an acute exercise protocol that consisted of a 35min continuous stationary cycle ergometry (Monark 828E, Monark Exercise AB, Varburg, Sweden). The two exercise protocols were either moderate-intensity continuous exercise (MICE) or alternating high- and low- intensity interval exercise (HIIE). MICE was performed at 65% of VO2peak and HIIE was performed at a ratio of 2:3 (120s at 50% VO2peak: 180s at 80% VO2peak). The workload was calculated as a percentage of power output achieved in the GXT, then converted into kilopond units and set as a fixed workload of the MICE and alternating workload for the HIIE. Further, telemetry-based HR and RPE (Borg CR10 scale) were recorded every 5min throughout the protocol. Intravenous blood sampling was drawn at pre-exercise, immediately- (0min), 2h- and 24h- post cycling intervention. Gastrointestinal symptoms were individually monitored and reported during, post- and 24h after exercise. Following another 7 d rest period, the participants arrived at the laboratory to complete the second exercise protocol. Each intervention was completed in Charles Sturt University Exercise Physiology Laboratory by the principal investigator who is an Exercise Sports Science Australia (ESSA) Accredited Exercise Scientist (AES) and was a PhD student at the time. They also have their Certificate in Pathology for venous blood collection. Each session was 1 on 1 between the participants and principal investigator. Direct supervision was provided by the principal investigator and would monitor exercise adherence by recording HR and RPE every 5 minutes, and changing resistance when required throughout the HIIE. This research was approved by the institutional ethic and biosafety committee.