Firefighter Thermoregulatory Responses in Active Fire With Betaine Supplementation


The goal of this clinical trial is to compare betaine supplementation to placebo in firefighters undergoing live burn training regarding thermoregulation and inflammation. The main questions it aims to answer are: – Does betaine supplementation mitigate rises in core temperature during firefighter live burn training? – Does betaine supplementation decrease inflammation from firefighter training? – Does betaine supplementation increase total body water stores? Participants will supplement with betaine for 1 month and complete: – Total Body Water measures – Body Composition measures – Live Burn training with Core Temperature Measurements – Provide Salivary samples

Full Title of Study: “Thermoregulatory Responses of Betaine Supplementation in Firefighters During Live Burn”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Prevention
    • Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
  • Study Primary Completion Date: March 2024


  • Dietary Supplement: Betaine
    • 3 grams per day for ~4 weeks
  • Dietary Supplement: Placebo
    • 3 grams per day for ~4 weeks

Arms, Groups and Cohorts

  • Placebo Comparator: Placebo
    • 10 participants will be given rice-flour as a placebo
  • Active Comparator: Betaine
    • 10 participants will be given betaine

Clinical Trial Outcome Measures

Primary Measures

  • Determine if BET supplementation impacts the thermal response in professional firefighters during live burn training.
    • Time Frame: 1 month
    • To address Aim 1, we will measure and record changes in core temperature and skin temperature. Temperature will be measured before, during, and after the live burn. Physiological strain index will be calculated based off initial core temperature and heart rate, as well as ending core temperature and heart rate during the live burn. Tegaderm patches will be worn during the live burn to analyze sodium concentration in sweat. Additionally, subjective thermal sensation, rate of perceived exertion, and thirst will be measured before and after the live burn.
  • Determine if BET supplementation impacts acute physiological stress in professional firefighters during a live burn.
    • Time Frame: 1 month
    • To address Aim 2, we will collect saliva samples before, immediately after, 10 minutes, and 20 minutes after live burn. These saliva samples will be analyzed for cortisol and testosterone to determine Testosterone Cortisol ratios and markers of inflammation (Interleukin 8 [IL-8] and interleukin-6 [IL-6]). Additionally, heart rate will be measured throughout the live burn. Last, pounds per square inch (PSI) in the firefighter’s air tank will be recorded to indicate the amount of air usage.

Secondary Measures

  • Determine if BET supplementation decreases chronic physiological stress in professional firefighters.
    • Time Frame: 2 months
    • To address Aim 3, we will collect saliva samples before and after the 4-week supplementation period to be analyzed for testosterone, cortisol, uric acid, and c-reactive protein. Resting blood pressure, total body water, and heart rate will also be measured.

Participating in This Clinical Trial

Inclusion Criteria

  • Structural Firefighter Exclusion Criteria:

  • • Participants have a cardiometabolic disease for which they take prescribed medications – Participants consume supplements known to impact hydration status or performance that they are not willing to stop taking for the study – Participants are pregnant – Female participants that have irregular menstrual cycles – Participants are injured and would not be able to fulfill the live burn scenario – Participants have sickle cell disease – Participants have experienced heat stroke within the last 2 years

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Michael J. Ormsbee
  • Provider of Information About this Clinical Study
    • Sponsor-Investigator: Michael J. Ormsbee, Director – Florida State University
  • Overall Contact(s)
    • Liliana Renteria, 8506451016,

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