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Active, Not Recruiting

NCT Number: NCT04979455

Risk Factors for Exertional Heat Illness

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 aim of this study is to examine traditional and novel risk factors that may increase thermal strain and EHI likelihood in military recruits undergoing strenuous physical exercise.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Exertional Heat Illness Heat Stress Disorders Wounds and Injuries

Age range

17 year–35 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Commando Training Centre Royal Marine

Lympstone, Devon, EX8 5AR, United Kingdom

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Men and women aged 17-35 years enrolled in military training

Exclusion criteria

  • Self-report as pregnant

Treatment and study plan

Core temperature monitoring

Other

Core temperature will be monitored on the day of exercise

Questionnaires

Behavioral

Questionnaires will be completed at baseline and on the day of exercise

Heart Rate Monitoring

Other

Heart rate will be monitored on the day of exercise

Urine collection

Other

Urine samples will be collected at baseline and on the day of exercise

Sleep monitoring

Other

Sleep will be monitored at baseline and on the day of exercise

Blood collection

Other

Blood samples will be completed at baseline

Saliva Collection

Other

Saliva samples will be collected at baseline and on the day of exercise

Throat swab collection

Other

Throat swab samples will be collected at baseline and on the day of exercise

Stool collection

Other

Stool samples will be collected at baseline and on the day of exercise

Primary outcomes

  1. Body mass index in EHI and control group

    Time frame: Baseline

  2. Fitness in EHI and control group - participants ranked by time to complete fitness test

    Time frame: Baseline

  3. Core temperature in EHI and control group

    Time frame: 1 Day

  4. Heart rate in EHI and control group

    Time frame: 2 Hours

  5. Urine osmolality in EHI and control group

    Time frame: Baseline

  6. Sleep quality and quantity, measured by Pittsburgh Sleep Quality Index, in EHI and control group

    Time frame: Throughout study - up to 1 week

    0-21 Scale. Higher score indicates worse outcome

  7. Sleep quality, measured by actigraphy, between EHI and control group

    Time frame: Throughout study - up to 1 week

  8. Sleep quantity, measured by actigraphy, between EHI and control group

    Time frame: Throughout study - up to 1 week

  9. Circulating Interleukin 6 in EHI and control group

    Time frame: Baseline

  10. Circulating C-Reactive Protein in EHI and control group

    Time frame: Baseline

  11. Circulating Creatine kinase in EHI and control group

    Time frame: Baseline

  12. Circulating Aspartate Aminotransferase in EHI and control group

    Time frame: Baseline

  13. Circulating Alanine Aminotransferase in EHI and control group

    Time frame: Baseline

  14. Circulating Claudin 3 in EHI and control group

    Time frame: Baseline

  15. Circulating Zonulin in EHI and control group

    Time frame: Baseline

  16. Circulating Lipopolysaccharide binding protein in EHI and control group

    Time frame: Baseline

  17. Circulating immunoglobulin E in EHI and control group

    Time frame: Baseline

  18. Salivary cortisol in EHI and control group

    Time frame: Throughout study - up to 1 week

  19. Detection of infectious pathogens in EHI and control groups

    Time frame: Throughout study - up to 1 week

  20. Respiratory illness symptomology, measured by Jackson common cold questionnaire, in EHI and control group

    Time frame: Throughout study - up to 1 week

    0-24 Scale. Higher score indicates worse outcome

  21. Gastrointestinal illness symptomology, measured by gastrointestinal symptoms questionnaire, in EHI and control group

    Time frame: Throughout study - up to 1 week

    0-10 Scale per symptom. Higher score indicates worse outcome

  22. Abundance and diversity of gastrointestinal microbiota in EHI and control group

    Time frame: Baseline

Sponsors and collaborators

Lead sponsor

Liverpool John Moores University

Other

Collaborators

  • Bangor University (UK)
  • CTCRM Lympstone (UK)
  • Defence Science and Technology (UK)
  • Headquarters Army Recruiting and Initial Training Command (UK)
  • Institute of Naval Medicine (UK)
  • Public Health Wales
  • University of Portsmouth

Registry information

Official study title

Prospective Investigation of Risk Factors for Exertional Heat Illness

Important dates

Study start
2021
Primary completion
2024
Study completion
2025
First posted
Jul 28, 2021
Registry last updated
Mar 19, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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