Exertional Heat IllnessNCT05303142
Comparing Exertional Heat Illness Risk Factors Between Patients and Controls
An observational study of Exertional Heat Illness, run by University of Portsmouth at 1 site in United Kingdom.
Trial summary
The arduous nature of military training and operations require personnel to encounter high heat load, e.g., during intense physical exertion, particularly in the heat. These conditions reduce operational effectiveness and expose personnel to a risk of incapacitation and death from exertional heat illness (EHI). Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Exertional Heat Illness
- What is being tested?
- Heat Tolerance Assessment
- How many people
- 95 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 1 Feb 2022to 6 Mar 2023
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: Individuals who have experienced a recent exertional heat illness and matched controls with no previous history of exertional heat illness
Who may be able to join
- Individuals with a history of EHI:
- Previous EHI episode
- Normal resting ECG
- Male or female
- 18 - 40 years
- Control participants:
Show all 10Show fewer
- No previous history of EHI
- Normal resting ECG
- Male or female
- 18 - 40 years
Who cannot join
None listed.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
University of Portsmouth
Portsmouth, Hampshire, PO1 2UP
About this study
Official title: Comparison of Novel Putative Risk Factors for Exertional Heat Illness Between a Military Patient Cohort and Matched Control Cohort During Exercise Heat Stress
The arduous nature of military training and operations require personnel to encounter high heat load, e.g., during intense physical exertion, particularly in the heat. These conditions reduce operational effectiveness and expose personnel to a risk of incapacitation and death from exertional heat illness (EHI). The primary aim of this study is to compare putative 'chronic' EHI risk factors between a cohort who have suffered a history of EHI and a control cohort with no EHI history. The secondary aim is to examine the influence of these EHI risk factors on thermoregulation during a standard heat tolerance assessment.
Read the detailed description
Military training and operations present a risk of incapacitation and death from Exertional Heat Illness (EHI). However, widely accepted EHI risk factors are absent in almost half of all United Kingdom (UK) military EHI cases, indicating that a significant number of EHI cases in military personnel involve alternative risk factors. Risk factors for EHI can been classified along a spectrum ranging from acute (e.g. recent poor sleep) to chronic (e.g. low fitness), with the role of chronic risk factors supported by the observation that individuals who have suffered an EHI are at a substantially increased risk of subsequent EHI. The primary aim of this study is to compare putative 'chronic' EHI risk factors (e.g. composition of gastrointestinal (GI) microbiome, infection and inflammation, trait-like psychological factors) between a cohort who have suffered a history of EHI and a control cohort with no EHI history. The secondary aim is to examine the influence of these EHI risk factors on thermoregulation during a standard heat tolerance assessment.
- Conditions
- Exertional Heat Illness
- Being tested
- Heat Tolerance Assessment
- Medical subject headings
- Heat Stress Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Heat Tolerance AssessmentOther
60-90 minutes exercise in hot (34 °C; 45% R.H.) conditions at 60%VO2max
| Study group | Role | What they receive |
|---|---|---|
| Individuals with a history of EHI | Service personnel who have a history of EHI. Receives: Other: Heat Tolerance Assessment | |
| Control participants without a history of EHI | Matched control participants with no history of EHI. They will be matched to the experimental group for parameters that are known to influence thermoregulatory responses to exercise heat-stress.
1. Relative aerobic fitness (V̇O2max; ml∙kg-1∙min-1)
2. Body mass (kg)
3. Body surface area (m2)
4. Age
5. Sex Receives: Other: Heat Tolerance Assessment |
What is being measured
The primary outcome is the main question the study is designed to answer.
Core temperature
Measured using a rectal thermistor.
Measured: At 60 minutes (or test termination if earlier) of Heat Tolerance Assessment
Core temperature
Measured using a rectal thermistor.
Measured: Rate of rise from 30 to 60 minutes (or test termination if earlier) of Heat Tolerance Assessment
Diversity of gastrointestinal microbiota
Measured in stool sample. Assessed by alpha diversity score.
Measured: Baseline
Diversity of gastrointestinal microbiota
Measured in stool sample. Assessed by beta diversity score.
Measured: Baseline
Abundance of gastrointestinal microbiota
Measured in stool sample. Assessed at level of phylum.
Measured: Baseline
Detection of sexually transmitted pathogens
Assessed from urine sample. Measured using cobas CT/NG assays.
Measured: Baseline
Detection of respiratory pathogens
Assessed from throat swab. Measured using Allplex assays.
Measured: Baseline
Detection of gastrointestinal pathogens
Assessed from stool swab. Measured using Allplex.
Measured: Baseline
Circulating Interleukin 6
Measured using ELISA
Measured: Baseline
Circulating Interleukin 6
Measured using ELISA
Measured: Post Heat Tolerance Assessment (within 15 minutes of test end)
Circulating C-Reactive Protein
Measured using ELISA
Measured: Baseline
Circulating C-Reactive Protein
Measured using ELISA
Measured: Post Heat Tolerance Assessment (within 15 minutes of test end)
Circulating Claudin 3
Measured using ELISA
Measured: Baseline
Circulating Claudin 3
Measured using ELISA
Measured: Post Heat Tolerance Assessment (within 15 minutes of test end)
Circulating Zonulin
Measured using ELISA
Measured: Baseline
Circulating lipopolysaccharide binding protein
Measured using ELISA
Measured: Baseline
Circulating lipopolysaccharide binding protein
Measured using ELISA
Measured: Post Heat Tolerance Assessment (within 15 minutes of test end)
Circulating intestinal fatty acid binding protein
Measured using ELISA
Measured: Baseline
Circulating intestinal fatty acid binding protein
Measured using ELISA
Measured: Post Heat Tolerance Assessment (within 15 minutes of test end)
Gastrointestinal illness symptomology questionnaire
Visual analogue scale (0-10). Higher scores indicate worse symptomology
Measured: Baseline
Gastrointestinal illness symptomology questionnaire
Visual analogue scale (0-10). Higher scores indicate worse symptomology
Measured: Pre Heat Tolerance Assessment
Gastrointestinal illness symptomology questionnaire
Visual analogue scale (0-10). Higher scores indicate worse symptomology
Measured: Immediately post Heat Tolerance Assessment
Respiratory illness symptomology, measured by Jackson common cold questionnaire
Higher scores indicate worse symptomology
Measured: Baseline
Sleep quality and quantity, measured by Pittsburgh Sleep Quality Index
Higher scores indicate worse sleep
Measured: Baseline -3 days
Motivation, measured by Motivation scale
Measured: Baseline -3 days
State-trait anxiety, measured by state-trait anxiety inventory form Y-2
Measured: Baseline -3 days
Risk taking, measured by the risk-taking inventory
Measured: Baseline -3 days
Resilience, measured by the Connor-Davidson resilience scale
Measured: Baseline -3 days
Stress, measured by perceived stress scale
Measured: Baseline -3 days
Mental readiness
Visual analogue scale (0-100). Higher scores indicate a lower state of mental readiness.
Measured: Baseline
Stress
Visual analogue scale (0-100). Higher scores indicate a greater state of stress.
Measured: Baseline
Secondary outcomes (6)
Heat rate
Measured: At 5 minute intervals during the Heat Tolerance Assessment
Thermal comfort
Modified 9 point Gagge scale. Higher scores indicate worse comfort.
Measured: At 15 minute intervals during Heat Tolerance Assessment
Thermal sensation
Modified 9 point Gagge scale. Higher scores indicate hotter sensation
Measured: At 15 minute intervals during Heat Tolerance Assessment
Rating of Perceived Exertion
6-20 Borg scale. Higher scores indicate higher perceived exertion
Measured: At 15 minute intervals during Heat Tolerance Assessment
Skin Temperature
Weighted mean skin temperature
Measured: During Heat Tolerance Assessment
Sweat rate
Determined from change in nude body mass during the heat tolerance assessment
Measured: During Heat Tolerance Assessment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Mar 2022
- Study start1 Feb 2022
- Primary completion6 Mar 2023
- Study completion6 Mar 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Exertional Heat IllnessStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Enrolment
- 95 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Portsmouth
- Sponsor type
- University, hospital or other
- Collaborators
- Liverpool John Moores University, Institute of Naval Medicine (UK), Headquarters Army Recruiting and Initial Training Command (UK), Public Health Wales
- Responsible party
- Principal investigator, Jo Corbett, University of Portsmouth
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05303142
- Sponsor's protocol ID
- 209321
- Status last verified
- May 2023
- First submitted
- 3 Feb 2022
- Last updated
- 22 May 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 May 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of Novel Putative Risk Factors for Exertional Heat Illness Between a Military Patient Cohort and Matched Control Cohort During Exercise Heat Stress
- ClinicalTrials.gov ID
- NCT05303142
- Acronym / sponsor ID
- 209321
- Conditions
- Exertional Heat Illness
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 95 participants (actual)
- Lead sponsor
- University of PortsmouthUniversity, hospital or other
- Collaborators
- Liverpool John Moores University, Institute of Naval Medicine (UK), Headquarters Army Recruiting and Initial Training Command (UK), Public Health Wales
- Study start
- 1 Feb 2022 (actual)
- Primary completion
- 6 Mar 2023 (actual)
- Study completion
- 6 Mar 2023 (actual)
- First posted
- 31 Mar 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The arduous nature of military training and operations require personnel to encounter high heat load, e.g., during intense physical exertion, particularly in the heat. These conditions reduce operational effectiveness and expose personnel to a risk of incapacitation and death from exertional heat illness (EHI). The primary aim of this study is to compare putative 'chronic' EHI risk factors between a cohort who have suffered a history of EHI and a control cohort with no EHI history. The secondary aim is to examine the influence of these EHI risk factors on thermoregulation during a standard heat tolerance assessment.
Detailed description
Military training and operations present a risk of incapacitation and death from Exertional Heat Illness (EHI). However, widely accepted EHI risk factors are absent in almost half of all United Kingdom (UK) military EHI cases, indicating that a significant number of EHI cases in military personnel involve alternative risk factors. Risk factors for EHI can been classified along a spectrum ranging from acute (e.g. recent poor sleep) to chronic (e.g. low fitness), with the role of chronic risk factors supported by the observation that individuals who have suffered an EHI are at a substantially increased risk of subsequent EHI. The primary aim of this study is to compare putative 'chronic' EHI risk factors (e.g. composition of gastrointestinal (GI) microbiome, infection and inflammation, trait-like psychological factors) between a cohort who have suffered a history of EHI and a control cohort with no EHI history. The secondary aim is to examine the influence of these EHI risk factors on thermoregulation during a standard heat tolerance assessment.
Study design
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Individuals with a history of EHI | – | Other: Heat Tolerance AssessmentService personnel who have a history of EHI. |
| Control participants without a history of EHI | – | Other: Heat Tolerance AssessmentMatched control participants with no history of EHI. They will be matched to the experimental group for parameters that are known to influence thermoregulatory responses to exercise heat-stress. 1. Relative aerobic fitness (V̇O2max; ml∙kg-1∙min-1) 2. Body mass (kg) 3. Body surface area (m2) 4. Age 5. Sex |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- Individuals who have experienced a recent exertional heat illness and matched controls with no previous history of exertional heat illness
Key inclusion criteria (10 listed)
- Previous EHI episode
- Normal resting ECG
- Male or female
- 18 - 40 years
- No previous history of EHI
Key exclusion criteria (0 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Heat Tolerance Assessment60-90 minutes exercise in hot (34 °C; 45% R.H.) conditions at 60%VO2max | Other | Control participants without a history of EHI, Individuals with a history of EHI |
Primary outcome
Core temperature
Time frame: At 60 minutes (or test termination if earlier) of Heat Tolerance Assessment
Measured using a rectal thermistor.
Core temperature
Time frame: Rate of rise from 30 to 60 minutes (or test termination if earlier) of Heat Tolerance Assessment
Measured using a rectal thermistor.
Diversity of gastrointestinal microbiota
Time frame: Baseline
Measured in stool sample. Assessed by alpha diversity score.
Diversity of gastrointestinal microbiota
Time frame: Baseline
Measured in stool sample. Assessed by beta diversity score.
Abundance of gastrointestinal microbiota
Time frame: Baseline
Measured in stool sample. Assessed at level of phylum.
Detection of sexually transmitted pathogens
Time frame: Baseline
Assessed from urine sample. Measured using cobas CT/NG assays.
Detection of respiratory pathogens
Time frame: Baseline
Assessed from throat swab. Measured using Allplex assays.
Detection of gastrointestinal pathogens
Time frame: Baseline
Assessed from stool swab. Measured using Allplex.
Circulating Interleukin 6
Time frame: Baseline
Measured using ELISA
Circulating Interleukin 6
Time frame: Post Heat Tolerance Assessment (within 15 minutes of test end)
Measured using ELISA
Circulating C-Reactive Protein
Time frame: Baseline
Measured using ELISA
Circulating C-Reactive Protein
Time frame: Post Heat Tolerance Assessment (within 15 minutes of test end)
Measured using ELISA
Circulating Claudin 3
Time frame: Baseline
Measured using ELISA
Circulating Claudin 3
Time frame: Post Heat Tolerance Assessment (within 15 minutes of test end)
Measured using ELISA
Circulating Zonulin
Time frame: Baseline
Measured using ELISA
Circulating lipopolysaccharide binding protein
Time frame: Baseline
Measured using ELISA
Circulating lipopolysaccharide binding protein
Time frame: Post Heat Tolerance Assessment (within 15 minutes of test end)
Measured using ELISA
Circulating intestinal fatty acid binding protein
Time frame: Baseline
Measured using ELISA
Circulating intestinal fatty acid binding protein
Time frame: Post Heat Tolerance Assessment (within 15 minutes of test end)
Measured using ELISA
Gastrointestinal illness symptomology questionnaire
Time frame: Baseline
Visual analogue scale (0-10). Higher scores indicate worse symptomology
Gastrointestinal illness symptomology questionnaire
Time frame: Pre Heat Tolerance Assessment
Visual analogue scale (0-10). Higher scores indicate worse symptomology
Gastrointestinal illness symptomology questionnaire
Time frame: Immediately post Heat Tolerance Assessment
Visual analogue scale (0-10). Higher scores indicate worse symptomology
Respiratory illness symptomology, measured by Jackson common cold questionnaire
Time frame: Baseline
Higher scores indicate worse symptomology
Sleep quality and quantity, measured by Pittsburgh Sleep Quality Index
Time frame: Baseline -3 days
Higher scores indicate worse sleep
Motivation, measured by Motivation scale
Time frame: Baseline -3 days
State-trait anxiety, measured by state-trait anxiety inventory form Y-2
Time frame: Baseline -3 days
Risk taking, measured by the risk-taking inventory
Time frame: Baseline -3 days
Resilience, measured by the Connor-Davidson resilience scale
Time frame: Baseline -3 days
Stress, measured by perceived stress scale
Time frame: Baseline -3 days
Mental readiness
Time frame: Baseline
Visual analogue scale (0-100). Higher scores indicate a lower state of mental readiness.
Stress
Time frame: Baseline
Visual analogue scale (0-100). Higher scores indicate a greater state of stress.
6 secondary outcomes
Heat rate
Time frame: At 5 minute intervals during the Heat Tolerance Assessment
Thermal comfort
Time frame: At 15 minute intervals during Heat Tolerance Assessment
Thermal sensation
Time frame: At 15 minute intervals during Heat Tolerance Assessment
Rating of Perceived Exertion
Time frame: At 15 minute intervals during Heat Tolerance Assessment
Skin Temperature
Time frame: During Heat Tolerance Assessment
Sweat rate
Time frame: During Heat Tolerance Assessment
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 May 2023.
- Individual participant dataSharing planned: No
Related trials for Exertional Heat Illness
Recruiting
Effects of Creatine Supplementation on Cognitive Measures and Markers of Acute Kidney Injury After Exercise in the Heat
Acute Kidney Injury, Exertional Heat Illness
Active, not recruitingObservational study
Treatment of Exertional Heatstroke witH icE wAter Soaked Towels
Heat Stroke Exertional, Heat Illness
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Exertional Heat Illness, run by University of Portsmouth at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 22 May 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Core temperature (time frame: At 60 minutes (or test termination if earlier) of Heat Tolerance Assessment). The study lists 31 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 May 2023.