Abstract
Firefighting activities trigger strong physiological stress responses, activating neuroendocrine and immune pathways. Yet little is known about how basal levels of inflammation influence the response to the demands of live-fire training evaluation (LFTE). PURPOSE: This study examined the difference of a firefighters’ (FFs) physiological stress responses by their basal inflammation level during an LFTE using an assumption-driven analytical approach to account for missing data. METHODS: Seventy-six FFs completed an LFTE. Salivary biosamples were taken before, immediately after, and 30 min post-LFTE, then analyzed for α-amylase (sAA), cortisol (sCORT), and secretory immunoglobulin A (SIgA). FFs were grouped by their basal level of inflammation (Inflam), as determined by their C-reactive protein levels that were categorized as follows: LOW: “Normal/Low Inflammation” = Less than 1.0 mg/L to 3.0 mg/L; or MOD: “Moderate Inflammation/Cardiovascular Risk” = 1.0–3.0 mg/L to 10 mg/L. Multiple imputation addressed missing data under a fully conditional specification, producing several complete datasets. Biomarker responses were normalized to baseline. GLMs were used with parameter estimates pooled across imputations per Rubin’s procedure rules. RESULTS: Multivariate effects were noted for (all p<0.001) for time (T; ηp2=0.133) and T x Inflam (ηp2=0.038). Univariate analysis revealed T x Inflam effects for sCORT (p<0.001, ηp2=0.044) and SIgA (p<0.001, ηp2=0.022), but not for sAA (p=0.098, ηp2=0.002). Pairwise comparisons revealed that sCORT levels were higher right after the LFTE (251% [202,299]; p<0.001) and 30 minutes post-LFTE (199% [163,235]; p<0.001) in the MOD group compared to the LOW Inflam group. Interestingly, the SIgA level right after the LFTE was lower in the MOD group than in the LOW Inflam group (-39% [-54,-24]; p<0.001). CONCLUSION: FFs with moderate basal inflammation show an exaggerated neuroendocrine stress response and a diminished mucosal immune response after an LFTE. This indicates that higher baseline inflammation might increase the risk of heightened stress reactivity and temporary immune suppression during operational stress.
Recommended Citation
Chovanetz, Jordyn; Conner, Michael; Martin, Steven E.; McAllister, Matthew J.; and Gonzalez, Drew E.
(2026)
"Basal Inflammation Modifies Neuroendocrine and Immune Stress Responses to Live Fire Training in Firefighters,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
18, Article 182.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss18/182