Risk Factors for Exertional Heat Illness

NCT04979455 | Active Not Recruiting

• 1 other identifier: 2029/MODREC/21
• Study Type: observational
• Target: 783
• 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 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.

Conditions

Exertional Heat Illness

Outcome Measures

Primary Outcomes (22)

• Body mass index in EHI and control group

  Baseline

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

  Baseline

• Core temperature in EHI and control group

  1 Day

• Heart rate in EHI and control group

  2 Hours

• Urine osmolality in EHI and control group

  Baseline

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

  0-21 Scale. Higher score indicates worse outcome

  Throughout study - up to 1 week

• Sleep quality, measured by actigraphy, between EHI and control group

  Throughout study - up to 1 week

• Sleep quantity, measured by actigraphy, between EHI and control group

  Throughout study - up to 1 week

• Circulating Interleukin 6 in EHI and control group

  Baseline

• Circulating C-Reactive Protein in EHI and control group

  Baseline

• Circulating Creatine kinase in EHI and control group

  Baseline

• Circulating Aspartate Aminotransferase in EHI and control group

  Baseline

• Circulating Alanine Aminotransferase in EHI and control group

  Baseline

• Circulating Claudin 3 in EHI and control group

  Baseline

• Circulating Zonulin in EHI and control group

  Baseline

• Circulating Lipopolysaccharide binding protein in EHI and control group

  Baseline

• Circulating immunoglobulin E in EHI and control group

  Baseline

• Salivary cortisol in EHI and control group

  Throughout study - up to 1 week

• Detection of infectious pathogens in EHI and control groups

  Throughout study - up to 1 week

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

  0-24 Scale. Higher score indicates worse outcome

  Throughout study - up to 1 week

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

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

  Throughout study - up to 1 week

• Abundance and diversity of gastrointestinal microbiota in EHI and control group

  Baseline

Study Arms (2)

Exertional heat illness

Participants who experience an atypical elevation in thermal strain or an EHI undergoing strenuous physical exercise.

Other: Core temperature monitoring; Behavioral: Questionnaires; Other: Heart rate monitoring; Other: Urine collection; Other: Sleep monitoring; Other: Blood collection; Other: Saliva collection; Other: Throat swab collection; Other: Stool collection

Control

Participants who do not experience an atypical elevation in thermal strain or an EHI undergoing strenuous physical exercise.

Other: Core temperature monitoring; Behavioral: Questionnaires; Other: Heart rate monitoring; Other: Urine collection; Other: Sleep monitoring; Other: Blood collection; Other: Saliva collection; Other: Throat swab collection; Other: Stool collection

Interventions

Core temperature monitoring OTHER

Core temperature will be monitored on the day of exercise

Control; Exertional heat illness

Questionnaires BEHAVIORAL

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

Control; Exertional heat illness

Heart rate monitoring OTHER

Heart rate will be monitored on the day of exercise

Control; Exertional heat illness

Urine collection OTHER

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

Control; Exertional heat illness

Sleep monitoring OTHER

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

Control; Exertional heat illness

Blood collection OTHER

Blood samples will be completed at baseline

Control; Exertional heat illness

Saliva collection OTHER

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

Control; Exertional heat illness

Throat swab collection OTHER

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

Control; Exertional heat illness

Stool collection OTHER

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

Control; Exertional heat illness

Eligibility Criteria

• Age: 17 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Participants who experience and participants who do not experience an atypical elevation in thermal strain or an EHI undergoing strenuous physical exercise.

You may qualify if:

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

You may not qualify if:

• Self-report as pregnant

Sponsors & Collaborators

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

Study Sites (1)

Commando Training Centre Royal Marine

Lympstone, Devon, EX8 5AR, United Kingdom

Location

Biospecimen

Retention: SAMPLES WITH DNA

Saliva sample, stool sample

MeSH Terms

Conditions

Heat Stress Disorders

Interventions

Surveys and Questionnaires; Urine Specimen Collection; Blood Specimen Collection

Condition Hierarchy (Ancestors)

Wounds and Injuries

Intervention Hierarchy (Ancestors)

Data Collection; Epidemiologic Methods; Investigative Techniques; Health Care Evaluation Mechanisms; Quality of Health Care; Health Care Quality, Access, and Evaluation; Public Health; Environment and Public Health; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 28, 2021
• First Posted: July 28, 2021
• Study Start: June 11, 2021
• Primary Completion: July 22, 2024
• Study Completion: July 1, 2025
• Last Updated: March 19, 2025

Record last verified: 2024-10

Data Sharing

• IPD Sharing: Will not share

Locations

GB (1)