Physiological stress responses to a live-fire training evolution in career structural firefighters.

OBJECTIVE: This study assessed firefighters' physiological stress response to a live fire training evolution (LFTE).

METHODS: Seventy-six (n = 76) firefighters completed an LFTE. Salivary samples were collected pre-, immediately post, and 30-min post-LFTE and analyzed for α-amylase (AA), cortisol (CORT), and secretory immunoglobulin-A (SIgA).

RESULTS: Concentrations of AA, CORT, and SIgA were elevated immediately post LFTE versus pre (p < 0.0001) and 30-min post (p < 0.0001). Cohen's d effect size comparing pre and immediately-post means were 0.83, 0.77, and 0.61 for AA, CORT, and SIgA, and were 0.54, 0.44, and 0.69 for AA, CORT, and SIgA, comparing immediately-post and 30-min post respectively.

CONCLUSIONS: These data demonstrate the stress response and activation of the hypothalamic-pituitary-adrenal/sympathetic-adreno-medullar axis and immune system immediately after real-world firefighting operations. Future work is needed to understand the impact of elevated stress biomarkers on firefighter performance and disease risk.