None listed
Conditions
Brief summary
Cardiorespiratory fitness (CRF) is the biggest predictor for chronic disease morbidity and mortality; however, one in five adults report little to no improvement in CRF (VO2max) following exercise training. Variability can be attributed to a myriad of factors, such as age, sex, gender and baseline VO2max. One of the biggest predictors is genetic make-up; which contributes to approximately 50% of VO2max trainability. From our systematic review, we identified nearly 100 genetic variants associated with VO2max trainability. Individuals can be given a gene predictor score (GPS) based on how many genetic variants they have that contribute to a high or low VO2max training response. Typically, there are fewer low responders with high intensity interval training (HIIT) compared to other forms of training. Individuals with a low GPS ideally should be prescribed a HIIT intervention over other forms of training for greater adaptations. Despite this, variability will still exist. There has been minimal, if any, research to identify the association between the gut microbiome (the bacteria that lives within our large intestines) and its effect on VO2peak trainability (our improvement in cardiorespiratory fitness). More specifically, is our GPS related to the bacteria within our gut; and can this gut bacteria be positively influenced to improve our cardiorespiratory training response? The overall objective of IMPROVE HIIT is to contribute to evidence-based personalised medicine. Understanding the factors that influence training variability that could be used to improve individualised exercise prescription, thereby contributing to health maintenance and treatment/prevention of disease. Aims: The aims of IMPROVE-HIIT include: 1) determining the association between our genetic make-up and the bacteria within our gut 2) investigating whether improving our gut bacteria via diet can influence our cardiorespiratory training response
Interventions
Improve HIIT is an 8-week randomised trial with two groups allocated to either: (1) HIIT plus placebo (maltodextrin - 12 g/day); or (2) HIIT plus prebiotic (12g/day).
Intervention Groups
All participants will be instructed to maintain their usual diet during the intervention period. This information will be outlined in the diary they are provided.
1. Oral spplementation adjustment period
Each group will have two weeks prior to the 6-week exercise intervention to gradually increase the dose o
Improve HIIT is an 8-week randomised trial with two groups allocated to either: (1) HIIT plus placebo (maltodextrin - 12 g/day); or (2) HIIT plus prebiotic (12g/day). Intervention Groups All participants will be instructed to maintain their usual diet during the intervention period. This information will be outlined in the diary they are provided. 1. Oral spplementation adjustment period Each group will have two weeks prior to the 6-week exercise intervention to gradually increase the dose of the oral supplementation from 2g to 12 g/day (6g/day twice daily) by the start of the 6-week intervention. The supplement will be increased every second day by 2g. This will be done to reduce unwanted side-effects in the prebiotic supplementation group, such as flatulence. The diary will indicate how much to progress by each day. The prebiotic is made up of fructo-oligosaccharide enriched inulin (which is a combination of longer and shorter chain inulin derived from chicory root). It comes in powder form that is easily dissolved in any liquid. Maltodextrin has been chosen as the placebo due to its slightly sweet taste (mimicking that of the prebiotic powder). Maltodextrin has been used as a placebo in other gut-related studies. 2. Exercise intervention and supplementation period Following the two-week supplementation adjustment period, each group will complete a 6-week HIIT exercise intervention period in conjunction with daily supplementation of a placebo or prebiotic. . HIIT protocol - 38 min in duration per session Participants will receive 3 supervised exercise sessions each week, over a 6-week period. These sessions will involve a 10-minute warm up at 60-70% of maximal heart rate (HRmax). Modality will be on the treadmill. Proceeding this 10 minutes, participants will work at 90-95% of their HRmax for 4 minutes, followed by a 3-minute active recovery (50-70% of HRmax). This will be repeated 4 times (4x4), followed by a 5-minute cool down. Training will occur at UQ, St. Lucia and will be supervised by exercise physiologists. This supervision may be 1-1 or in groups of 5. The participants will be asked to maintain their usual activities of daily living without increasing or changing their structured exercise outside of the study. Intervention group 1 - HIIT plus placebo (HIIT-M). Participants will be required to take a placebo each day for the 6-week intervention period (12g of maltodextrin (My Protein, United Kingdom). Participants will be required to complete 3 supervised sessions of HIIT per week for the 6 weeks. Participants will be asked to keep a diary. Intervention group 2 - HIIT + Prebiotic (HIIT-P) Participants will be required to take 12g of an oligofructose enriched inulin powder each day (Prebiotin, USA) during the 6-week exercise intervention. Participants will be required to complete 3 supervised sessions of HIIT per week for the 6 weeks. Participants will be asked to keep a diary.
Sponsors
University of Queensland
Study design
Allocation
Randomised controlled trial
Primary purpose
Prevention
Masking
Blinded (masking used) (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
• Inactive adults aged between 18 and 50 years • Less than 60 minutes of structured exercise each week • Signed consent form
Exclusion criteria
• Antibiotic use 6 months prior to intervention or antibiotic use during intervention. • Pre- or-probiotic use within four weeks of participating in study • Pregnancy, chronic infections, auto-immune diseases and intestinal chronic conditions (e.g. IBS, Chrohn’s disease, ulcerative colitis, coeliac disease). • Existing cardiac conditions • Recent surgery or orthopaedic conditions that prevents treadmill walking/running • Diabetes • Allergies to inulin (chicory root) or fructans • Allergies to maltodextrin and other polysaccharides • Allergies to soy, milk and egg (there maybe traces of these in maltodextrin) • Greater than 60 minutes of exercise per week within four weeks of the study
Outcome results
None listed