Comparing Exertional Heat Illness Risk Factors Between Patients and Controls

NCT05303142 | Completed

• 1 other identifier: 209321
• Study Type: observational
• Target: 95
• Locations: 1 country
• Sites: 1

Brief 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). 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.

Conditions

Exertional Heat Illness

Outcome Measures

Primary Outcomes (31)

• Core temperature

  Measured using a rectal thermistor.

  At 60 minutes (or test termination if earlier) of Heat Tolerance Assessment

• Core temperature

  Measured using a rectal thermistor.

  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.

  Baseline

• Diversity of gastrointestinal microbiota

  Measured in stool sample. Assessed by beta diversity score.

  Baseline

• Abundance of gastrointestinal microbiota

  Measured in stool sample. Assessed at level of phylum.

  Baseline

• Detection of sexually transmitted pathogens

  Assessed from urine sample. Measured using cobas CT/NG assays.

  Baseline

• Detection of respiratory pathogens

  Assessed from throat swab. Measured using Allplex assays.

  Baseline

• Detection of gastrointestinal pathogens

  Assessed from stool swab. Measured using Allplex.

  Baseline

• Circulating Interleukin 6

  Measured using ELISA

  Baseline

• Circulating Interleukin 6

  Measured using ELISA

  Post Heat Tolerance Assessment (within 15 minutes of test end)

• Circulating C-Reactive Protein

  Measured using ELISA

  Baseline

• Circulating C-Reactive Protein

  Measured using ELISA

  Post Heat Tolerance Assessment (within 15 minutes of test end)

• Circulating Claudin 3

  Measured using ELISA

  Baseline

• Circulating Claudin 3

  Measured using ELISA

  Post Heat Tolerance Assessment (within 15 minutes of test end)

• Circulating Zonulin

  Measured using ELISA

  Baseline

• Circulating lipopolysaccharide binding protein

  Measured using ELISA

  Baseline

• Circulating lipopolysaccharide binding protein

  Measured using ELISA

  Post Heat Tolerance Assessment (within 15 minutes of test end)

• Circulating intestinal fatty acid binding protein

  Measured using ELISA

  Baseline

• Circulating intestinal fatty acid binding protein

  Measured using ELISA

  Post Heat Tolerance Assessment (within 15 minutes of test end)

• Gastrointestinal illness symptomology questionnaire

  Visual analogue scale (0-10). Higher scores indicate worse symptomology

  Baseline

• Gastrointestinal illness symptomology questionnaire

  Visual analogue scale (0-10). Higher scores indicate worse symptomology

  Pre Heat Tolerance Assessment

• Gastrointestinal illness symptomology questionnaire

  Visual analogue scale (0-10). Higher scores indicate worse symptomology

  Immediately post Heat Tolerance Assessment

• Respiratory illness symptomology, measured by Jackson common cold questionnaire

  Higher scores indicate worse symptomology

  Baseline

• Sleep quality and quantity, measured by Pittsburgh Sleep Quality Index

  Higher scores indicate worse sleep

  Baseline -3 days

• Motivation, measured by Motivation scale

  Baseline -3 days

• State-trait anxiety, measured by state-trait anxiety inventory form Y-2

  Baseline -3 days

• Risk taking, measured by the risk-taking inventory

  Baseline -3 days

• Resilience, measured by the Connor-Davidson resilience scale

  Baseline -3 days

• Stress, measured by perceived stress scale

  Baseline -3 days

• Mental readiness

  Visual analogue scale (0-100). Higher scores indicate a lower state of mental readiness.

  Baseline

• Stress

  Visual analogue scale (0-100). Higher scores indicate a greater state of stress.

  Baseline

Secondary Outcomes (6)

• Heat rate

  At 5 minute intervals during the Heat Tolerance Assessment

• Thermal comfort

  At 15 minute intervals during Heat Tolerance Assessment

• Thermal sensation

  At 15 minute intervals during Heat Tolerance Assessment

• Rating of Perceived Exertion

  At 15 minute intervals during Heat Tolerance Assessment

• Skin Temperature

  During Heat Tolerance Assessment

Other Outcomes (3)

• Body mass

  Baseline

• Relative maximal aerobic fitness

  Baseline

• Urine osmolality

  Baseline

Study Arms (2)

Individuals with a history of EHI

Service personnel who have a history of EHI.

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

Other: Heat Tolerance Assessment

Interventions

Heat Tolerance Assessment OTHER

60-90 minutes exercise in hot (34 °C; 45% R.H.) conditions at 60%VO2max

Control participants without a history of EHI; Individuals with a history of EHI

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Individuals who have experienced a recent exertional heat illness and matched controls with no previous history of exertional heat illness

You may qualify if:

• Individuals with a history of EHI:
• Previous EHI episode
• Normal resting ECG
• Male or female
• years
• Control participants:
• No previous history of EHI
• Normal resting ECG
• Male or female
• years

Sponsors & Collaborators

• University of Portsmouth: lead
• Liverpool John Moores University: collaborator
• Institute of Naval Medicine (UK): collaborator
• Headquarters Army Recruiting and Initial Training Command (UK): collaborator
• Public Health Wales: collaborator

Study Sites (1)

University of Portsmouth

Portsmouth, Hampshire, PO1 2UP, United Kingdom

Location

Biospecimen

Retention: SAMPLES WITH DNA

Saliva; plasma; stool

MeSH Terms

Conditions

Heat Stress Disorders

Condition Hierarchy (Ancestors)

Wounds and Injuries

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: February 3, 2022
• First Posted: March 31, 2022
• Study Start: February 1, 2022
• Primary Completion: March 6, 2023
• Study Completion: March 6, 2023
• Last Updated: May 22, 2023

Record last verified: 2023-05

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)