Integrating Cognitive Assessments Into the Heat Tolerance Test After Exertional Heat Injury

Cognitive Assessment During Heat Tolerance Test

This prospective observational study is to evaluate soldiers post-exertional heat injury (EHI) during a heat tolerant test (HTT) to investigate the impact on their cognitive performance.

Study Overview

• Status: Completed
• Conditions: Exertional Heat Injury

Detailed Description

The objective of the proposed research is to add a cognitive evaluation to the physiological parameters monitored in the heat tolerance test (HTT) and to construct a new cognitive-physiological model for evaluation based on the accumulated knowledge on soldiers' heat tolerance. Each year, in the Israel Defense Forces (IDF), approximately 50 soldiers post exertional heat injury (EHI) are referred to perform the HTT. The HTT is carried out approximately one month post injury as part of clinical evaluation of the patient and is also intended to determine return to duty for combatants in field units. Currently, the criteria used in the HTT to determine heat tolerance are based solely on physiological parameters, while no cognitive evaluation is utilized in the HTT. Noteworthy are the numerous studies published in scientific literature describing the influence of exposure to heat conditions and physical effort on cognition and psychological strain in humans.

The subjects performing the HTT will also undergo cognitive evaluation and psychological strain assessment using tests used and validated in the research laboratories of the United States military (USARIEM). The cognitive evaluation will be performed in addition to the validated physiological monitoring performed in the HTT. All gathered physiological and cognitive data will be used to construct new bio-statistical models and new criteria will be suggested for the definition of heat tolerance or intolerance.

• Study Type: Observational
• Enrollment (Actual): 70

Contacts and Locations

Study Locations

• Israel
  • Tel Hashomer, Israel
    • Heller Institute, Institute of Military Physiology, IDF Medical Corps

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Israeli Defense Forces combat soldiers

Description

Inclusion Criteria:

• Combat soldiers post exertional heat injury

Exclusion Criteria:

• Additional medical condition restricting combat duty

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Combat soldiers post exertional heat injury; Participants were classified into heat-intolerant (HI) or heat-tolerant (HT) groups based on their HTT physiological outcomes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants Classified as Heat-Intolerant during Heat Tolerant Test	Participants are classified as heat-intolerant if they exhibit any of the following indicators during the Heat Tolerance Test: a core body temperature (Tre) ≥ 38.5°C (≥ 101.38°F), a heart rate (HR) ≥ 150 bpm, or failure to achieve a Tre-to-HR ratio ≥ 0.2798°C ∙ bpm-¹. Participants meeting none of these criteria are classified as heat-tolerant.	120 minutes

Collaborators and Investigators

• Sponsor: Medical Corps, Israel Defense Force
• Collaborators: The Chaim Sheba Medical Center
• Investigators: Study Director: Daniel S Moran, PhD, Institute of Military Physiology, IDF Medical Corps, Tel Hashomer, Israel

Publications and helpful links

General Publications

• Moran DS, Shitzer A, Pandolf KB. A physiological strain index to evaluate heat stress. Am J Physiol. 1998 Jul;275(1):R129-34. doi: 10.1152/ajpregu.1998.275.1.R129.
• Epstein Y, Sohar E, Shapiro Y. Exertional heatstroke: a preventable condition. Isr J Med Sci. 1995 Jul;31(7):454-62.
• Moran DS, Heled Y, Still L, Laor A, Shapiro Y. Assessment of heat tolerance for post exertional heat stroke individuals. Med Sci Monit. 2004 Jun;10(6):CR252-7. Epub 2004 Jun 1.
• Moran DS, Erlich T, Epstein Y. The heat tolerance test: an efficient screening tool for evaluating susceptibility to heat. J Sport Rehabil. 2007 Aug;16(3):215-21. doi: 10.1123/jsr.16.3.215.

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2018
• Primary Completion (Actual): December 21, 2024
• Study Completion (Actual): December 21, 2024

Study Registration Dates

• First Submitted: December 24, 2024
• First Submitted That Met QC Criteria: January 1, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 1, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Keywords: Cognitive Impairment; Heat Tolerance Test; Exertional heat injury; Thermoregulatory Function
• Additional Relevant MeSH Terms: Wounds and Injuries; Burns
• Other Study ID Numbers: IDF- 123 1779-2017

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The data for this belong to the Israel Defense Forces and the Israel Ministry of Defense. Data sharing will be considered if the corresponding author receives a reasonable request and establishes an institution-to-institution data-sharing agreement.
• IPD Sharing Time Frame: The data are available, and sharing will be considered if the corresponding author receives a reasonable request and establishes an institution-to-institution data-sharing agreement.
• IPD Sharing Access Criteria: Sharing will be considered if the corresponding author receives a reasonable request and establishes an institution-to-institution data-sharing agreement.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No