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Trial registered on ANZCTR


Registration number
ACTRN12618000501246
Ethics application status
Approved
Date submitted
1/03/2018
Date registered
6/04/2018
Date last updated
13/07/2021
Date data sharing statement initially provided
15/03/2019
Date results information initially provided
13/07/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
Improving the response to high intensity interval training through the ingestion of a daily prebiotic fibre.
Scientific title
Improving High Intensity Interval Training (HIIT) Response in healthy adults by enhancing the gut microbiome through a daily prebiotic supplementation
Secondary ID [1] 294171 0
Nil known
Universal Trial Number (UTN)
Trial acronym
IMPROVE HIIT
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Cardiorespiratory fitness 306814 0
Condition category
Condition code
Diet and Nutrition 305921 305921 0 0
Other diet and nutrition disorders
Cardiovascular 306355 306355 0 0
Normal development and function of the cardiovascular system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
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.
Intervention code [1] 300490 0
Treatment: Other
Comparator / control treatment
Control group will receive a placebo (maltodextrin) instead of a prebiotic fibre supplement. Both groups receive high intensity interval training.
Control group
Placebo

Outcomes
Primary outcome [1] 304975 0
An incremental treadmill test to exhaustion will be completed to ascertain VO2peak. This test will be the Bruce Ramp protocol. This test will be assessed via indirect calorimetry and will determine VO2peak directly.
Timepoint [1] 304975 0
Pre and post 6 week exercise intervention (8 weeks post randomisation).
Primary outcome [2] 305236 0
A panel of genetic variants that are correlated with VO2peak training reponse will be identified from a saliva sample collected via an Oragene collection kit. Saliva samples will be sent to the Translational Research Institute (TRI) for DNA extraction and GWAS analysis.
Timepoint [2] 305236 0
Baseline
Secondary outcome [1] 343776 0
Gut diversity/bioinformatics and short-chain fatty acid (SCFA) analysis will be performed on faecal samples collected Participants will be provided with a home stool collection kit with instructions. They will be asked to keep stool sample frozen until their next testing visit. After this time, the stool samples will be kept at -80 degrees Celsius until analysis. One stool sample will be kept for short chain fatty acid analysis at the University of Qld, and two other stool samples will be sent to Microba for testing.
Timepoint [1] 343776 0
Baselineand 8 weeks.
Secondary outcome [2] 344564 0
A food frequency questionnaire will be collected at baseline and at 8 weeks (completed at testing visit 1). Analysis will be completed by Microba (Australia). To control for diet and to assess whether there is an interaction between dietary inulin and supplement inulin, a 24-hour diet recall at baseline and post intervention will be collected during the second testing visit using the (The Automated Self-Administered 24-hour (ASA24) Dietary Assessment Tool developed by the National Cancer Institute (NCI)). This will be analysed using Food Works, Xyris, Australia (a nutrient analysis software).
Timepoint [2] 344564 0
Baseline and 8 weeks post intervention.
Secondary outcome [3] 344566 0
Body composition will be measured at baseline and 8 weeks. Measurements will include height, weight, waist and hip measurements. Circumferences will be calculated to the nearest 0.1 decimal using a measuring tape. Weight will be measure to the nearest 0.1 decimal using calibrated scales. Body fat will be measured via a Duel-energy X-ray Absorptiometry – DXA scan (Hologic QDR Series, Massachusetts, USA). The participant will be required to lay still in a supine position for approximately seven minutes.
Timepoint [3] 344566 0
Baseline and 8 weeks
Secondary outcome [4] 344568 0
A person trained in phlebotomy will take blood at baseline and 8 weeks. A small sample of venous blood will be collected from the superficial antecubital vein using 2 x 10ml vacutainers (red and purple vacutainers). The purple vacutainers (used for measuring whole blood and contain EDTA) will be placed on ice. The red vacutainers (contains no anticoagulant and used for serum) will remain at room temperature for 30 minutes. Before centrifuging, 3 x 300ul of whole blood will be collected for back up and placed in the freezer at -80 degrees Celsius. Remaining samples will be centrifuged at 1500G for 10 minutes at 4 degrees Celsius. Plasma and serum will be placed into 300ul aliquots and stored at -80degrees Celsius until analysis. Analysis of total cholesterol, HDL, LDL, triglycerides and glucose will be measured on an automated clinical chemistry analyser (Randox Datomer Plus) using the manufacturer’s procedures.
Timepoint [4] 344568 0
Baseline and 8 weeks
Secondary outcome [5] 344570 0
Mental health will be assessed by using The Center for Epidemiologic Studies Depression Scale (CEDS),
Timepoint [5] 344570 0
Baseline and 8 weeks.

Eligibility
Key inclusion criteria
• Inactive adults aged between 18 and 50 years
• Less than 60 minutes of structured exercise each week
• Signed consent form
Minimum age
18 Years
Maximum age
50 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key 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

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Prior to the first testing session of the first participant, sequentially numbered opaque sealed envelopes will be used to randomly allocate participants to one of two intervention groups: 1) High intensity interval training plus placebo (maltodextrin) (HIIT-M), or 2) High intensity interval training plus prebiotic powder (HIIT-P)
‘HIIT-M’ written on carbon paper will be inside 20 of the opaque envelopes. ‘HIIT-P’ written on carbon paper will be inside the remaining 20 opaque envelopes. These 40 envelopes will be shuffled several times in the presence of at least two investigators.
Participants will be given a code to deidentify them for this study. For example, participant ‘a’ may have the code IMPROVE HIIT_01. Once participants have been deidentified with a code, these codes will be sequentially placed on the outside of the shuffled envelopes. This procedure will be done in the presence of two investigators involved in the study.
Participants will be blinded as to which supplement they are using. Aside from the principal investigator, researchers involved in the study will be blinded as to which supplement each participant is using. Only the principal investigator will have access to the master code.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Prior to the first testing session of the first participant, sequentially numbered opaque sealed envelopes will be used to randomly allocate participants to one of two intervention groups: 1) High intensity interval training plus placebo (maltodextrin) (HIIT-M), or 2) High intensity interval training plus prebiotic powder (HIIT-P)
‘HIIT-M’ written on carbon paper will be inside 20 of the opaque envelopes. ‘HIIT-P’ written on carbon paper will be inside the remaining 20 opaque envelopes. These 40 envelopes will be shuffled several times in the presence of at least two investigators.
Participants will be given a code to deidentify them for this study. For example, participant ‘a’ may have the code IMPROVE HIIT_01. Once participants have been deidentified with a code, these codes will be sequentially placed on the outside of the shuffled envelopes. This procedure will be done in the presence of two investigators involved in the study.
Participants will be blinded as to which supplement they are using. Aside from the principal investigator, researchers involved in the study will be blinded as to which supplement each participant is using. Only the principal investigator will have access to the master code.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
1/06/2018
Actual
21/01/2019
Date of last participant enrolment
Anticipated
23/08/2019
Actual
30/05/2019
Date of last data collection
Anticipated
23/10/2019
Actual
1/08/2019
Sample size
Target
40
Accrual to date
Final
40
Recruitment in Australia
Recruitment state(s)
QLD

Funding & Sponsors
Funding source category [1] 298806 0
University
Name [1] 298806 0
Bond University: Collaborative Research Network for Advancing Exercise & Sports Science (CRN-AESS)
Country [1] 298806 0
Australia
Primary sponsor type
University
Name
University of Queensland
Address
School of Human Movement and Nutrition Sciences
Level 5, Human Movement Studies Building (26B), Blair Drive
Room 535
The University of Queensland
St Lucia QLD 4072
Country
Australia
Secondary sponsor category [1] 298037 0
None
Name [1] 298037 0
Address [1] 298037 0
Country [1] 298037 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 299752 0
NHMRC (HREA)
Ethics committee address [1] 299752 0
School of Human Movement and Nutrition Sciences
Level 5, Human Movement Studies Building (26B), Blair Drive
The University of Queensland
St Lucia QLD 4072
Ethics committee country [1] 299752 0
Australia
Date submitted for ethics approval [1] 299752 0
26/02/2018
Approval date [1] 299752 0
23/04/2018
Ethics approval number [1] 299752 0

Summary
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
Trial website
Trial related presentations / publications
Public notes
Attachments [1] 3199 3199 0 0
/AnzctrAttachments/374601-Improve HIIT Protocol_Final_23042018.pdf (Protocol)
Attachments [2] 3200 3200 0 0
/AnzctrAttachments/374601-Improve HIIT PICF_Final_23042018.pdf (Participant information/consent)
Attachments [3] 3201 3201 0 0
/AnzctrAttachments/374601-2018000398 - Approval Form.pdf (Ethics approval)

Contacts
Principal investigator
Name 81462 0
Ms Camilla Williams
Address 81462 0
School of Human Movement and Nutrition Sciences
Level 5, Human Movement Studies Building (26B), Blair Drive
Room 535
The University of Queensland
St Lucia QLD 4072
Country 81462 0
Australia
Phone 81462 0
+61417191613
Fax 81462 0
Email 81462 0
camilla.williams@uq.net.au
Contact person for public queries
Name 81463 0
Ms Camilla Williams
Address 81463 0
School of Human Movement and Nutrition Sciences
Level 5, Human Movement Studies Building (26B), Blair Drive
Room 535
The University of Queensland
St Lucia QLD 4072
Country 81463 0
Australia
Phone 81463 0
+61417191613
Fax 81463 0
Email 81463 0
camilla.williams@uq.net.au
Contact person for scientific queries
Name 81464 0
Ms Camilla Williams
Address 81464 0
School of Human Movement and Nutrition Sciences
Level 5, Human Movement Studies Building (26B), Blair Drive
Room 535
The University of Queensland
St Lucia QLD 4072
Country 81464 0
Australia
Phone 81464 0
+61417191613
Fax 81464 0
Email 81464 0
camilla.williams@uq.net.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
Need to confirm with researchers involved in study.


What supporting documents are/will be available?

TypeCitationLinkEmailOther DetailsAttachment
Study protocol    374601-(Uploaded-14-03-2019-12-17-07)-Study-related document.pdf


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
SourceTitleYear of PublicationDOI
EmbaseOligofructose-Enriched Inulin Intake, Gut Microbiome Characteristics, and the VO2Peak Response to High-Intensity Interval Training in Healthy Inactive Adults.2022https://dx.doi.org/10.1093/jn/nxab426
EmbaseGenome wide association study of response to interval and continuous exercise training: the Predict-HIIT study.2021https://dx.doi.org/10.1186/s12929-021-00733-7
N.B. These documents automatically identified may not have been verified by the study sponsor.