Physiological Responses to Heat Stress During High-risk Events

NCT06907225 | Recruiting

• 1 other identifier: 24-29
• Study Type: observational
• Target: 150
• Locations: 1 country
• Sites: 2

Brief Summary

Exertional heat stroke (EHS) affects \~500 Military Personnel and over 100 Soldiers every year, and it is believed that these numbers are underreported. EHS is the most severe form of exertional heat illness (EHI) and can result in substantial, long-lasting organ damage, and even death in severe cases. Based on current knowledge and training needs, it is impossible to prevent every EHS - which shifts the focus from exclusively prevention to a combination of prevention, treatment, and enhancing recovery as much as possible. While many risk factors have been identified and there are adequate treatments available, biomarkers associated with heat stroke risk, recovery, and return-to-duty (RTD) remain largely unclear. The purpose of the proposed study is to enhance knowledge surrounding biomarkers of EHS and long-term health consequences that result from EHS. The investigators will recruit research volunteers for a field study in order to collect pre-, post-, and follow-up measures from a high-risk EHS event (i.e. ruck marches, timed runs) this will allow us to have a basis for comparison between Soldiers who collapse with EHS (from previously collected data) and those that complete high-risk events, but do not collapse. This will allow for comparison between the groups to identify EHS-specific biomarkers that could aid in recovery and RTD decisions for Soldiers.

Conditions

Thermoregulation

Keywords

Thermoregulation; Heat illness

Outcome Measures

Primary Outcomes (5)

• Core temperature

  Body temperature recorded during training

  Collected only during training, pre-exercisce, post-exercise, and after recovery (from 0-36 hours)

• Creatinine from blood serum

  Serum creatinine measures to evaluate kidney function

  Measured at least once every 6 hours for up to 36 hours

• Alanine aminotransferase from blood samples

  Measure of liver function (ALT) from blood

  Measured at least once every 6 hours for up to 36 hours

• Aspartate aminotransferase (AST)

  Liver function measure (AST) from blood

  Measured at least once every 6 hours for up to 36 hours

• Heart rate

  Heart rate measured during activity

  Measured during training only from start of training up to completion (~4 hours)

Secondary Outcomes (3)

• Urinary KIM-1

  Measured at least once every 6 hours for up to 36 hours

• Urinary creatinine

  Measured at least once every 6 hours for up to 36 hours

• Blood sodium concentration

  Measured at least once every 6 hours for up to 36 hours

Interventions

None-placebo OTHER

None - observational study

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The sample population included in this investigation will be that of Soldiers undergoing high-risk training events in military training. There are no gender, race, or ethnicity limitations.

You may qualify if:

• Individuals (to include cis- and transgender males and females and nonbinary) 18 years of age or greater
• Current military service (active, Reserve, or National Guard)
• Currently participating in training

You may not qualify if:

• Females who are pregnant
• Any individual currently on a physical profile that restricts running or foot marching
• History of obstructive disease of the gastrointestinal tract including (but not limited to) diverticulosis, diverticulitis and inflammatory bowel disease, peptic ulcer disease, Crohn's disease, ulcerative colitis.
• Scheduled MRI within 2 weeks after core temp pill ingestion
• Known allergies to skin adhesive
• Blood donation in the past 8 weeks

Sponsors & Collaborators

• United States Army Research Institute of Environmental Medicine: lead

Study Sites (2)

Fort Novosel

Fort Novosel, Alabama, 36362, United States

RECRUITING

Field Study

Fort Jackson, South Carolina, 29207, United States

NOT YET RECRUITING

Related Publications (2)

• Roberts WO, Armstrong LE, Sawka MN, Yeargin SW, Heled Y, O'Connor FG. ACSM Expert Consensus Statement on Exertional Heat Illness: Recognition, Management, and Return to Activity. Curr Sports Med Rep. 2021 Sep 1;20(9):470-484. doi: 10.1249/JSR.0000000000000878.

  PMID: 34524191 BACKGROUND

• Williams VF, Oh GT. Update: Heat illness, active component, U.S. Armed Forces, 2021. MSMR. 2022 Apr 1;29(4):8-14.

  PMID: 35608520 BACKGROUND

Biospecimen

Retention: SAMPLES WITHOUT DNA

Blood and urine samples (without DNA) will be retained for biological analysis

MeSH Terms

Conditions

Heat Stress Disorders

Condition Hierarchy (Ancestors)

Wounds and Injuries

Central Study Contacts

Gabrielle E Giersch, PhD

CONTACT

508-206-2421; gabrielle.e.giersch.civ@health.mil

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: FED
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Research Physiologist

Study Record Dates

• First Submitted: March 24, 2025
• First Posted: April 2, 2025
• Study Start: May 31, 2025
• Primary Completion: September 30, 2025
• Study Completion (Estimated): September 1, 2026
• Last Updated: May 5, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

US (2)