The effect of high intensity exercise training on gut microbiota in humans

The intervention will consist of be an initial visit to the laboratory at the University of Auckland Grafton campus to screen participants, gain their informed consent, record anthropometrics and body composition, prior to undergoing a cardiorespiratory fitness to estimate VO2max. This information will be used to tailor the intensity of the exercise-training visits. Participants will also be asked to give a oral swab and a blood sample and fill in a food frequency questionnaire. This visit is scheduled to take a maximum of 2 hours. There will be nine high intensity exercise training visits over a period of 3 weeks with each visit being separated by at least 1 day of rest. Each training session is scheduled to be a maximum of 45 mins long including warm up and cool down periods. The intervention will be delivered by a masters student at either the Health and Performance Clinic at University of Auckland Tamaki campus or the laboratory at the Grafton Campus (the same venue as the first visit) depending on the preference of the participant. The masters student is an experienced athlete who has participated in stationary cycle training for 25 years and supervised training sessions throughout that period. The student investigator also holds a St Johns first aid certificate. During these visits, after a short warm up participants will be asked to complete 8-12 repetitions of 60 seconds high intensity cycling on a stationary bike with 75 seconds rest between each repetition. The intensity of the repetition will be between 80-100% of peak power as measured by the VO2 max test. A short recovery "cool down" period will conclude the exercise session. The masters student investigator will brief the each participant and demonstrate the operation of the stationary cycle prior to the first exercise session. The first block of 3 exercise sessions will consist of 8 high intensity intervals, the second and third blocks of 3 sessions consisting of 10 and 12 high intensity intervals respectively. The final visit of the intervention will be repeat the anthropometrics, body composition, VO2 max test, and blood sample at the Grafton campus as per the first visit. This visit is scheduled to take no more than 75mins (one and a quarter hours). Participants will be asked to provide 2 stool samples and 2 oral swab samples using the self collection kits provided between visits 1 and 2 and again between visits 10 and 11. The intervention will be administered face to face (except self sample collection as detailed above). Participants can attend the intervention individually, however, it will be possible for participants to undergo the exercise training in a small group (5 people or less) if they prefer. The student investigator will assess adherence to the intervention by recording participant attendance. Fidelity will be assessed by the student investigator supervising the exercise tests and training directly and downloading power output information from the stationary bike after each visit.