Andrea R. Bryant1, Matthew J. McAllister2, Hunter S. Waldman1. 1University of North Alabama, Florence, AL. 2Texas State University, San Marcos, TX.

BACKGROUND: Firefighting is demanding, creating a unique situation that presents the firefighter with a dual-stress challenge (i.e. simultaneous physical and mental stress). Dual-stress challenges, such as a live-burn, victim search and rescue (S&R), are known to exacerbate markers of cardiovascular disease more so, than a single physical or mental stress alone. To date, no study has attempted to determine if the fire grounds test (FGT) mimics the metabolic and physiological demands of firefighting. METHODS: Twenty-eight firefighters were recruited for this study. In a counterbalanced design, fourteen firefighters were randomized to complete either a FGT or a S&R. The FGT consisted of a victim removal, hose deployment, ladder carry, room search, stair climb, a forced entry and ceiling breach, and a roof walk. The S&R consisted of firefighters searching for three ‘victims (i.e. 100 kg dummies) inside a burning building while also attempting to extinguish the fire. Markers of stress (cortisol, uric acid, interleukin-1 beta) were collected pre, immediately post, and 30 min post each task to examine the metabolic demands. Additionally, heart rate and air depletion (PSI) were measured immediately post each task to examine the physiological demands. Stress markers were analyzed with a 2-way mixed model repeated measures analysis of variance. Physiological markers were measured with an independent t test. RESULTS: For stress markers, there was a significant interaction found for interleukin-1 beta (P=0.008). Post hoc analysis found that the S&R elevated circulating interleukin-1 beta concentrations, 30 min post task compared to the FGT. For cortisol, there were no significant interactions or main effects found (P>0.05). However, a time effect was found (P=0.007). Overall, cortisol was higher in both groups immediately post-task, compared to baseline. There were no further differences for uric acid or immediate post heart rate and PSI between either group (P>0.05). CONCLUSIONS: Physiological markers were not different between the FGT and S&R groups. Interleukin-1 beta demonstrated a greater increase to the S&R task when compared to the FGT. Our data show that the FGT may not mimic the metabolic demands of actual firefighting. Therefore, fire departments may want to consider adding an additional mental stressor and/or environmental stress to their entry test which closer mimics the demands of firefighting.

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