Comparing Exertional Heat Illness Risk Factors Between Patients and Controls

Exertional Heat Illness Clinical Trial

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT05303142
• Other study ID #: 209321
• Status: Completed
• Start date: February 1, 2022
• Est. completion date: March 6, 2023

Study information

• Verified date: May 2023
• Source: University of Portsmouth
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical 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). 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 95
• Est. completion date: March 6, 2023
• Est. primary completion date: March 6, 2023
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 40 Years

Eligibility

Inclusion Criteria:

Individuals with a history of EHI:

• Previous EHI episode

• Normal resting ECG

• Male or female

• 18 - 40 years

Control participants:

• No previous history of EHI

• Normal resting ECG

• Male or female

• 18 - 40 years

Related Conditions & MeSH terms

• Exertional Heat Illness
• Heat Stress Disorders

Intervention

Other:
• Heat Tolerance Assessment
60-90 minutes exercise in hot (34 °C; 45% R.H.) conditions at 60%VO2max

Locations

Country	Name	City	State
United Kingdom	University of Portsmouth	Portsmouth	Hampshire

Sponsors (5)

Lead Sponsor	Collaborator
University of Portsmouth	Headquarters Army Recruiting and Initial Training Command (UK), Institute of Naval Medicine (UK), Liverpool John Moores University, Public Health Wales (UK)

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Body mass		Baseline
Other	Relative maximal aerobic fitness	Highest value measured in ml.kg-1.min-1 during a treadmill graded exercise test.	Baseline
Other	Urine osmolality	Measured using freezing point depression	Baseline
Primary	Core temperature	Measured using a rectal thermistor.	At 60 minutes (or test termination if earlier) of Heat Tolerance Assessment
Primary	Core temperature	Measured using a rectal thermistor.	Rate of rise from 30 to 60 minutes (or test termination if earlier) of Heat Tolerance Assessment
Primary	Diversity of gastrointestinal microbiota	Measured in stool sample. Assessed by alpha diversity score.	Baseline
Primary	Diversity of gastrointestinal microbiota	Measured in stool sample. Assessed by beta diversity score.	Baseline
Primary	Abundance of gastrointestinal microbiota	Measured in stool sample. Assessed at level of phylum.	Baseline
Primary	Detection of sexually transmitted pathogens	Assessed from urine sample. Measured using cobas CT/NG assays.	Baseline
Primary	Detection of respiratory pathogens	Assessed from throat swab. Measured using Allplex assays.	Baseline
Primary	Detection of gastrointestinal pathogens	Assessed from stool swab. Measured using Allplex.	Baseline
Primary	Circulating Interleukin 6	Measured using ELISA	Baseline
Primary	Circulating Interleukin 6	Measured using ELISA	Post Heat Tolerance Assessment (within 15 minutes of test end)
Primary	Circulating C-Reactive Protein	Measured using ELISA	Baseline
Primary	Circulating C-Reactive Protein	Measured using ELISA	Post Heat Tolerance Assessment (within 15 minutes of test end)
Primary	Circulating Claudin 3	Measured using ELISA	Baseline
Primary	Circulating Claudin 3	Measured using ELISA	Post Heat Tolerance Assessment (within 15 minutes of test end)
Primary	Circulating Zonulin	Measured using ELISA	Baseline
Primary	Circulating lipopolysaccharide binding protein	Measured using ELISA	Baseline
Primary	Circulating lipopolysaccharide binding protein	Measured using ELISA	Post Heat Tolerance Assessment (within 15 minutes of test end)
Primary	Circulating intestinal fatty acid binding protein	Measured using ELISA	Baseline
Primary	Circulating intestinal fatty acid binding protein	Measured using ELISA	Post Heat Tolerance Assessment (within 15 minutes of test end)
Primary	Gastrointestinal illness symptomology questionnaire	Visual analogue scale (0-10). Higher scores indicate worse symptomology	Baseline
Primary	Gastrointestinal illness symptomology questionnaire	Visual analogue scale (0-10). Higher scores indicate worse symptomology	Pre Heat Tolerance Assessment
Primary	Gastrointestinal illness symptomology questionnaire	Visual analogue scale (0-10). Higher scores indicate worse symptomology	Immediately post Heat Tolerance Assessment
Primary	Respiratory illness symptomology, measured by Jackson common cold questionnaire	Higher scores indicate worse symptomology	Baseline
Primary	Sleep quality and quantity, measured by Pittsburgh Sleep Quality Index	Higher scores indicate worse sleep	Baseline -3 days
Primary	Motivation, measured by Motivation scale		Baseline -3 days
Primary	State-trait anxiety, measured by state-trait anxiety inventory form Y-2		Baseline -3 days
Primary	Risk taking, measured by the risk-taking inventory		Baseline -3 days
Primary	Resilience, measured by the Connor-Davidson resilience scale		Baseline -3 days
Primary	Stress, measured by perceived stress scale		Baseline -3 days
Primary	Mental readiness	Visual analogue scale (0-100). Higher scores indicate a lower state of mental readiness.	Baseline
Primary	Stress	Visual analogue scale (0-100). Higher scores indicate a greater state of stress.	Baseline
Secondary	Heat rate		At 5 minute intervals during the Heat Tolerance Assessment
Secondary	Thermal comfort	Modified 9 point Gagge scale. Higher scores indicate worse comfort.	At 15 minute intervals during Heat Tolerance Assessment
Secondary	Thermal sensation	Modified 9 point Gagge scale. Higher scores indicate hotter sensation	At 15 minute intervals during Heat Tolerance Assessment
Secondary	Rating of Perceived Exertion	6-20 Borg scale. Higher scores indicate higher perceived exertion	At 15 minute intervals during Heat Tolerance Assessment
Secondary	Skin Temperature	Weighted mean skin temperature	During Heat Tolerance Assessment
Secondary	Sweat rate	Determined from change in nude body mass during the heat tolerance assessment	During Heat Tolerance Assessment