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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] 311932 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Heat illness 333524 0
Condition category
Condition code
Injuries and Accidents 330204 330204 0 0
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] 328393 0
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] 337953 0
Core temperature
Timepoint [1] 337953 0
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] 433866 0
Heart rate
Timepoint [1] 433866 0
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] 433867 0
Thermal sensation
Timepoint [2] 433867 0
Baseline (start of the 10 km time trial) and every subsequent 2.5 km during the time trial in all sessions.
Secondary outcome [3] 433868 0
Thermal discomfort
Timepoint [3] 433868 0
Baseline (start of the 10 km time trial) and every subsequent 2.5 km during the time trial in all sessions.
Secondary outcome [4] 433869 0
Rating of perceived exertion
Timepoint [4] 433869 0
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] 433870 0
Skin temperature
Timepoint [5] 433870 0
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] 433871 0
Whole body sweat loss
Timepoint [6] 433871 0
Before and after the 10 km time trial during each session
Secondary outcome [7] 433872 0
Hydration status
Timepoint [7] 433872 0
30 minutes prior to the the 10 km time trial for the three experimental sessions
Secondary outcome [8] 433873 0
10 km time trial performance
Timepoint [8] 433873 0
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
14
Accrual to date
9
Final
Recruitment in Australia
Recruitment state(s)
SA

Funding & Sponsors
Funding source category [1] 316277 0
University
Name [1] 316277 0
University of South Australia
Country [1] 316277 0
Australia
Funding source category [2] 316278 0
Charities/Societies/Foundations
Name [2] 316278 0
Sports Medicine Australia Research Foundation
Country [2] 316278 0
Australia
Primary sponsor type
University
Name
University of South Australia
Address
Country
Australia
Secondary sponsor category [1] 318467 0
None
Name [1] 318467 0
Address [1] 318467 0
Country [1] 318467 0
Other collaborator category [1] 283004 0
University
Name [1] 283004 0
University of Canberra
Address [1] 283004 0
Country [1] 283004 0
Australia
Other collaborator category [2] 283005 0
University
Name [2] 283005 0
The University of Sydney
Address [2] 283005 0
Country [2] 283005 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 315096 0
University of South Australia Human Research Ethics Committee
Ethics committee address [1] 315096 0
https://i.unisa.edu.au/staff/research/research-ethics/human-research-ethics/
Ethics committee country [1] 315096 0
Australia
Date submitted for ethics approval [1] 315096 0
04/05/2023
Approval date [1] 315096 0
23/05/2023
Ethics approval number [1] 315096 0
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 133666 0
Dr Samuel Chalmers
Address 133666 0
University of South Australia, GPO Box 2471, Adelaide, SA, 5001
Country 133666 0
Australia
Phone 133666 0
+61 08 8302 1307
Fax 133666 0
Email 133666 0
samuel.chalmers@unisa.edu.au
Contact person for public queries
Name 133667 0
Chelsea Blackman
Address 133667 0
University of South Australia, GPO Box 2471, Adelaide, SA, 5001
Country 133667 0
Australia
Phone 133667 0
+61 08 8302 1307
Fax 133667 0
Email 133667 0
chelsea.blackman@mymail.unisa.edu.au
Contact person for scientific queries
Name 133668 0
Samuel Chalmers
Address 133668 0
University of South Australia, GPO Box 2471, Adelaide, SA, 5001
Country 133668 0
Australia
Phone 133668 0
+61 08 8302 1307
Fax 133668 0
Email 133668 0
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.