ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12624000606583

Ethics application status

Approved

Date submitted

12/04/2024

Date registered

9/05/2024

Date last updated

9/05/2024

Date data sharing statement initially provided

9/05/2024

Type of registration

Retrospectively registered

Titles & IDs

Public title

Informing extreme heat policy development in long distance running

Scientific title

Informing extreme heat policy development in long distance running in healthy males and females

Secondary ID [1]

Nil known

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

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

Heat illness

Condition category

Condition code

Injuries and Accidents

Other injuries and accidents

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Materials and procedures:
-Once enrolled into the study, participants will complete one familiarisation session and three experimental trials in an environmental chamber. Every session will involve only an individual participant completing the trials.
-Each experimental session will take approximately 2 hours and are undertaken 4-7 days apart.
-The familiarisation session will occur 4-7 days prior to the first experimental session take approximately 3 hours and requires participants to complete an incremental test to exhaustion and a 10 km time trial on the treadmill. The incremental test to exhaustion will be conducted in temperate conditions (22°C and 50% RH) on a calibrated motorised treadmill at 1% incline with a metabolic cart to measure gas exchange. The test will consist of initial four minute submaximal steady state exercise intensities, followed by the speed of the treadmill increasing by 1 km/h every minute until volitional exhaustion.
- The three experimental sessions require the participant to complete a 10 km running self-paced time trial on a treadmill in three environmental risk ratings (one per session);
- RISKmoderate (30°C and 45% RH)
- RISKhigh (28.5°C and 76% RH)
- RISKextreme (32.5°C and 68% RH)

The minimum period of days that the intervention can be completed over is 18 days. A study calendar will be used to manage adherence to the study sessions.

The risk ratings are categorised according to publicly available extreme heat policies.

Who will deliver:
A sport science graduate will lead data collection, and the remainder of the team are experienced researchers with 10-30 years of academic experience.

Mode:
In-person testing of individual participants

Location:
Environmental chamber at the University of South Australia

Intervention code [1]

Prevention

Comparator / control treatment

Participants act as their own control in this crossover observational study (active control group).

(Note: There is no designated 'reference' trial since each of the outcomes for all trials will be compared to each other trial)

Control group

Active

Outcomes

Primary outcome [1]

Core temperature

Timepoint [1]

Monitored continuously during the entire duration of the 10 km time trial for each experimental session. Core temperature will be measured via two sensors:
1) An ingestible sensor that is consumed 6-8 prior to each session (actual core temperature).
2) CALERAresearch by greenTEG device that is placed over the top of the chest (estimated core temperature). Placed on the participant within 15 minutes prior to the time trial in each session.

Secondary outcome [1]

Heart rate

Timepoint [1]

Fitted within 15 minutes prior to the time-trial or incremental test to exhaustion, and then monitored continuously during the entire duration of each activity (10 km time trial and incremental test to exhaustion).

Secondary outcome [2]

Thermal sensation

Timepoint [2]

Baseline (start of the 10 km time trial) and every subsequent 2.5 km during the time trial in all sessions.

Secondary outcome [3]

Thermal discomfort

Timepoint [3]

Baseline (start of the 10 km time trial) and every subsequent 2.5 km during the time trial in all sessions.

Secondary outcome [4]

Rating of perceived exertion

Timepoint [4]

Baseline (start of the 10 km time trial and incremental test to exhaustion) and either every subsequent 2.5 km during the time trial or every 1 minute during the incremental test to exhaustion.

Secondary outcome [5]

Skin temperature

Timepoint [5]

Fitted within 30 minutes prior to the time-trial and then monitored continuously during the entire duration of the 10 km time trial for all sessions.

Secondary outcome [6]

Whole body sweat loss

Timepoint [6]

Before and after the 10 km time trial during each session

Secondary outcome [7]

Hydration status

Timepoint [7]

30 minutes prior to the the 10 km time trial for the three experimental sessions

Secondary outcome [8]

10 km time trial performance

Timepoint [8]

End of the 10 km time trial for all sessions

Eligibility

Key inclusion criteria

Trained long-distance runners who are: males and females aged between 18-55 and are training at least three times per week with local level representation

Minimum age

18 Years

Maximum age

55 Years

Sex

Both males and females

Can healthy volunteers participate?

Yes

Key exclusion criteria

Not passing Stage 1 of the ESSA pre-exercise screening tool.

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)

Since the study is a crossover design, participants were not randomly allocated to groups, but were randomly allocated the trial order via blocked randomisation

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Blocked randomisation (without blinding) by the lead data collector

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Crossover

Other design features

Phase

Not Applicable

Type of endpoint/s

Efficacy

Statistical methods / analysis

1) Null hypothesis testing to compare the participant responses to the three environmental conditions using common statistical approaches to the Sport Science literature.

2) Comparison of physiological outcomes during each environmental risk condition against known thresholds that represent biological risk and intensity.

Recruitment

Recruitment status

Recruiting

Date of first participant enrolment

Anticipated

Actual

10/08/2023

Date of last participant enrolment

Anticipated

5/08/2024

Actual

Date of last data collection

Anticipated

30/08/2024

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

Funding & Sponsors

Funding source category [1]

University

Name [1]

University of South Australia

Address [1]

Country [1]

Australia

Funding source category [2]

Charities/Societies/Foundations

Name [2]

Sports Medicine Australia Research Foundation

Address [2]

Country [2]

Australia

Primary sponsor type

University

Name

University of South Australia

Address

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Other collaborator category [1]

University

Name [1]

University of Canberra

Address [1]

Country [1]

Australia

Other collaborator category [2]

University

Name [2]

The University of Sydney

Address [2]

Country [2]

Australia

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

University of South Australia Human Research Ethics Committee

Ethics committee address [1]

https://i.unisa.edu.au/staff/research/research-ethics/human-research-ethics/

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

04/05/2023

Approval date [1]

23/05/2023

Ethics approval number [1]

205513

Summary

Brief summary

A lack of validation data exists that compares the response of exercising individuals in different heat illness risk rating categories proposed by publicly available extreme heat policies for sport and exercise. The project aims to validate and inform publicly available extreme heat policies for long distance running by observing the heat strain of runners exercising in environmental conditions that are graded as moderate, high, and extreme environmental risk ratings according to the policies. 

We hypothesise that a progressively graded and higher response in thermoregulatory (core temperature), cardiovascular (heart rate), and perceptual measures (thermal discomfort) will be observed when moving from moderate to high to extreme risk environments. We also hypothesise that the extreme risk rating category will be associated with the participants approaching a core temperature response that is typically deemed as a 'cut-off' for exercise.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Samuel Chalmers

Address

University of South Australia, GPO Box 2471, Adelaide, SA, 5001

Country

Australia

Phone

+61 08 8302 1307

Fax

samuel.chalmers@unisa.edu.au

Contact person for public queries

Name

Chelsea Blackman

Address

University of South Australia, GPO Box 2471, Adelaide, SA, 5001

Country

Australia

Phone

+61 08 8302 1307

Fax

chelsea.blackman@mymail.unisa.edu.au

Contact person for scientific queries

Name

Samuel Chalmers

Address

University of South Australia, GPO Box 2471, Adelaide, SA, 5001

Country

Australia

Phone

+61 08 8302 1307

Fax

samuel.chalmers@unisa.edu.au

Data sharing statement

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

Yes

What data in particular will be shared?

Deidentified data may be provided for all relevant outcomes that are requested.

When will data be available (start and end dates)?

For at least 5 years following the publication in a peer-review scientific journal

Available to whom?

Other researchers can request deidentified data be made available upon request to the principle investigator.

Available for what types of analyses?

Not specific

How or where can data be obtained?

Email the primary contact of the study.
Dr Samuel Chalmers
E: samuel.chalmers@unisa.edu.au

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

No additional documents have been identified.

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