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Physiological Stress Responses to a Live-Fire Training Evolution in Career Structural Firefighters
Drew E Gonzalez1, Courtney C Dillard, Sarah E Johnson
1From the Tactical Athlete Research Unit, Department of Kinesiology & Sport Management, Texas A&M University, College Station, Texas (D.E.G., S.E.J., S.E.M.); Exercise Biochemistry Laboratory, Department of Kinesiology, University of North Alabama, Florence, Alabama (C.C.D.); Sydney and JL Huffines Institute for Sports Medicine and Human Performance, Department of Kinesiology & Sport Management, Texas A&M University, College Station, Texas (S.E.M.); and Metabolic and Applied Physiology Laboratory, Department of Health & Human Performance, Texas State University, San Marcos, Texas (C.C.D., M.J.M.).
Firefighters exhibit significant physiological stress after live fire training evolutions. Biomarkers for stress and immune response, including alpha-amylase, cortisol, and secretory IgA, were elevated immediately post-training.
Area of Science:
- Occupational Health
- Physiology
- Immunology
Background:
- Firefighting involves intense physical and psychological demands.
- Understanding the physiological stress response is crucial for firefighter well-being.
Purpose of the Study:
- To evaluate the acute physiological stress response in firefighters during a live fire training evolution (LFTE).
Main Methods:
- Seventy-six firefighters underwent an LFTE.
- Salivary samples were collected pre-, immediately post-, and 30-min post-LFTE.
- Analysis included alpha-amylase (AA), cortisol (CORT), and secretory immunoglobulin-A (SIgA).
Main Results:
- AA, CORT, and SIgA concentrations significantly increased immediately post-LFTE compared to pre-training levels (P<0.001).
- Elevated levels persisted at 30-min post-LFTE, though some biomarkers showed a slight decrease.
- Effect sizes indicated moderate to large increases in stress biomarkers immediately after the evolution.
Conclusions:
- Live fire training evolutions induce a significant acute stress response in firefighters.
- This response involves the activation of the hypothalamic-pituitary-adrenal axis, the sympathetic-adreno-medullar system, and the immune system.
- Further research is needed to link these stress biomarkers to performance and long-term health risks.
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Exercise Stress Test
Exercise stress testing, commonly known as a treadmill test, is a noninvasive procedure used to evaluate cardiovascular function and diagnose heart conditions.
Definition
An exercise stress test measures the heart's response to exertion using a treadmill or stationary bicycle. Chest electrodes record the heart's electrical activity through an ECG, and blood pressure is monitored regularly.
Purposes
Hypothalamic-Pituitary Axis

