Exertional Heat Illness: Biomarkers for Prediction and Return to Duty

Heat Illness Clinical Trial

— Heat3  

Official title:

Exertional Heat Illness: Biomarkers for Prediction and Return to Duty

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01434979
• Other study ID #: G191FY
• Status: Completed
• Start date: July 2011
• Est. completion date: February 2016

Study information

• Verified date: October 2019
• Source: Henry M. Jackson Foundation for the Advancement of Military Medicine
• Contact: n/a
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

The investigators goal is to monitor and quantify the differential physiologic and biomarker responses of controls to standardized exercise under thermoneutral and thermally challenged conditions and responses of exertional heat stroke (EHS) subjects under a thermal-challenged environment to develop unique bio-signature panels to predict those at risk for exertional heat illness (EHI) and guide return to duty following an episode of EHS.

Description:

Purpose: Our goal is to monitor and quantify the differential physiologic and biomarker responses of controls to standardized exercise under thermoneutral and thermally challenged conditions and responses of exertional heat stroke (EHS) subjects under a thermal-challenged environment to develop unique biosignature panels to predict those at risk for exertional heat illness (EHI) and guide return to duty following an episode of EHS.

Research Design: This is a prospective cross-sectional study.

Methodology/Technical Approach: The proposed study will examine multiple biomarkers in a group of 100 individuals who have not had an episode of EHS and a prospective study of 50 persons who have had an EHS event. Control subjects will have biomarker assessments before and after an exercise challenge under thermoneutral (TTT) and thermally challenged conditions (heat tolerance test/HTT); differences in the responses to the two tests will be attributed to the heat. In EHS subjects, blood will be obtained at time of injury and then followed up at 6 weeks according to non-EHS controls. In addition, EHS cases will be prospectively followed at 3, 6, 12, and 18 months after the 6-week post assessment. If they are heat tolerant at 6-weeks as determined by a HTT, subsequent measures will include only blood samples and questionnaires, whereas if they are heat intolerant (HIT) at 6-weeks, subsequent measures will include additional HTTs, along with blood samples and questionnaires. As our previous data indicate, approximately 20% of non-EHS persons are HIT; we will test 100 non-EHS and 50 EHI persons in this study. Thus, data will be evaluated with regard to thermotolerance. Importantly, all control participants will undergo two test sessions (HTT and TTT); to control for an order effect, we will randomize the tests.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 148
• Est. completion date: February 2016
• Est. primary completion date: February 2016
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 45 Years

Eligibility

Inclusion Criteria:

• Federal Civilian Employee, Active Duty, or DoD Beneficiary

• Between the ages of 18 and 45 years

• Waist circumference = 39.4 inches (100 cm)

• Willing to walk/run on a treadmill

• Willing to undergo exposure in a thermal chamber

• Willing to maintain their current activity patterns, and to abstain from alcohol, caffeine, and tobacco for 24 hours prior to all sessions

• For cases who have suffered from a exertional heat illness / exertional heat stroke, must have a clinically documented heat stroke within the past year

Exclusion Criteria:

• History of malignant hyperthermia

• Pregnant or lactating

• Have overt heart disease

• Have systolic blood pressure over 140 mm Hg, or diastolic pressure over 90 mm Hg

• Have a waist circumference > 39.4 inches (100 cm)

• Are older than 45 or younger than 18 years of age

• Are anemic

• Are taking psychotropic medication for any mental health disorder

• Are taking other selected medications (glucose lowering, prednisone or beta blockers)

Related Conditions & MeSH terms

• Heat Illness

Locations

Country	Name	City	State
Israel	Heller Institute of Medical Research	Tel-Hashomer
United States	Uniformed Services University of the Health Sciences	Bethesda	Maryland

Sponsors (1)

Lead Sponsor	Collaborator
Henry M. Jackson Foundation for the Advancement of Military Medicine

Countries where clinical trial is conducted

United States,  Israel, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Blood pressure in response to heat tolerance	Blood pressure will be recorded to see whether it blood pressure response to exercise in the heat correlates with heat tolerance.	2-hour heat tolerance test and 2-hour control test
Primary	Heat tolerance	Heat tolerance is determined by physiologic response to a 2-hour heat tolerance test. During this test, participants with core temperature greater than 38.5 C and/or heart rate greater than 150 bpm are considered heat intolerant.	2-hour heat test
Secondary	Fitness	Body fat and aerobic capacity will be measured to quantify their contribution to heat tolerance.	2-hour heat tolerance test
Secondary	Behavioral correlates of heat tolerance	Questionnaires will be used to assess behavioral correlates of heat tolerance, including measures of sleep impairment and executive dysfunction.	past month
Secondary	Perceived heat strain	Measures of perceived heat strain will be recorded to determine how accurately participants perceive that they are working in the heat, and whether this adds diagnostic value to the heat test.	2-hour heat tolerance test and 2-hour control test