Abstract
Firefighting can exacerbate cardiovascular disease (CVD) risk and has been shown to elevate α-amylase (AA), secretory immunoglobulin-A (SIgA), and cortisol. Data suggest firefighters may not meet cardiorespiratory fitness (CRF) standards. It is unclear if CRF levels impact the stress response to firefighting. Given the premature mortality risk, there is a critical need to understand the impact of CRF on firefighting stress responses. PURPOSE: This study assessed the impact of CRF on the stress response to an LFTE. METHODS: Forty-four (n=44) firefighters completed a cardiopulmonary exercise test (CPXT) and an LFTE. V̇O 2max was estimated via the Foster equation. The occupational CRF standard of 42 ml/kg/min was used to establish a low-fitness group (LF; n=22) and a high-fitness group (HF; n=22). Salivary samples were collected pre (baseline), immediately post, and 30-min post the LFTE and analyzed for AA, SIgA, and cortisol. Data were analyzed via a general linear model (GLM) multivariate and univariate analysis. RESULTS: GLM multivariate analysis revealed an overall time effect (p<0.001, ηₚ²=0.218) with no group x time effect (p=0.622, ηₚ²=0.026) for the salivary stress biomarkers. The univariate analysis revealed time effects for AA (p<0.001, ηₚ²=0.248), SIgA (p<0.001, ηₚ²=0.262), and cortisol (p=0.002, ηₚ²=0.140); however, no group x time effects were found for AA (p=0.486, ηₚ²=0.015), SIgA (p=0.502, ηₚ²=0.015), and cortisol (p=0.978, ηₚ²=0.000). Significantly higher AA (p=0.003), SIgA (p=0.003), and cortisol (p=0.003) concentrations were noted immediately post-LFTE than baseline concentrations. Only AA concentrations remained elevated at 30-min post-LFTE compared to baseline (p=0.003). There were no significant group effects for AA (p=0.261, ηₚ²=0.030), CORT (p=0.768, ηₚ²=0.002), or SIgA (p=0.353, ηₚ²=0.021). CONCLUSION: These data demonstrate the CRF level does not impact the physiological stress response to firefighting. Certainly, it is reasonable to believe that a more fit firefighter will be able to carry out physically demanding occupational tasks; however, future work should elucidate the impact that CRF may have on the stress response to fire-suppressive activities.
Recommended Citation
Kirkegaard, Leah; Hines, Kelly; Sowinski, Ryan J.; Martin, Steven E.; Colvin, Lisa C.; McAllister, Matthew J.; and Gonzalez, Drew E.
(2025)
"No Impact of Cardiorespiratory Fitness on The Stress Responses to Firefighting,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
17, Article 163.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss17/163
