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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

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]

Nil known

Universal Trial Number (UTN)

Trial acronym

IMPROVE HIIT

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Cardiorespiratory fitness

Condition category

Condition code

Diet and Nutrition

Other diet and nutrition disorders

Cardiovascular

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]

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]

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]

Pre and post 6 week exercise intervention (8 weeks post randomisation).

Primary outcome [2]

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]

Baseline

Secondary outcome [1]

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]

Baselineand 8 weeks.

Secondary outcome [2]

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]

Baseline and 8 weeks post intervention.

Secondary outcome [3]

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]

Baseline and 8 weeks

Secondary outcome [4]

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]

Baseline and 8 weeks

Secondary outcome [5]

Mental health will be assessed by using The Center for Epidemiologic Studies Depression Scale (CEDS),

Timepoint [5]

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)

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

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

QLD

Funding & Sponsors

Funding source category [1]

University

Name [1]

Bond University: Collaborative Research Network for Advancing Exercise & Sports Science (CRN-AESS)

Address [1]

Bond University
Collaborative Research Network for Advancing Exercise & Sports Science (CRN-AESS)
14 University Drive, ROBINA QLD
4226 AUSTRALIA

Country [1]

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]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

NHMRC (HREA)

Ethics committee address [1]

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]

Australia

Date submitted for ethics approval [1]

26/02/2018

Approval date [1]

23/04/2018

Ethics approval number [1]

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]

/AnzctrAttachments/374601-Improve HIIT Protocol_Final_23042018.pdf (Protocol)

Attachments [2]

/AnzctrAttachments/374601-Improve HIIT PICF_Final_23042018.pdf (Participant information/consent)

Attachments [3]

/AnzctrAttachments/374601-2018000398 - Approval Form.pdf (Ethics approval)

Contacts

Principal investigator

Name

Ms Camilla Williams

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

Phone

+61417191613

Fax

camilla.williams@uq.net.au

Contact person for public queries

Name

Camilla Williams

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

Phone

+61417191613

Fax

camilla.williams@uq.net.au

Contact person for scientific queries

Name

Camilla Williams

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

Phone

+61417191613

Fax

camilla.williams@uq.net.au

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

No/undecided IPD sharing reason/comment

Need to confirm with researchers involved in study.

What supporting documents are/will be available?

Doc. No.	Type	Citation	Link	Email	Other Details	Attachment
1623	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

Source	Title	Year of Publication	DOI
Embase	Genome wide association study of response to interval and continuous exercise training: the Predict-HIIT study.	2021	https://dx.doi.org/10.1186/s12929-021-00733-7
Embase	Oligofructose-Enriched Inulin Intake, Gut Microbiome Characteristics, and the VO2Peak Response to High-Intensity Interval Training in Healthy Inactive Adults.	2022	https://dx.doi.org/10.1093/jn/nxab426

N.B. These documents automatically identified may not have been verified by the study sponsor.

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