PHYSIOLOGICAL STRAIN AMONG FIRE FIGHTERS PERFORMING NON-FIRE EMERGENCY SERVICES

Grant Malone1, Nicholas Barefoot1, Anne M. Mulholland1, Jacob Mota2, Colleen Geary1, Hayley MacDonald1. 1The University of Alabama, Tuscaloosa, AL. 2Texas Tech University, Lubbock, TX. BACKGROUND: Cardiac fatalities are the leading cause of death amongst firefighters (FFs) in the US. Poor cardiovascular health is an important mediator of this high prevalence. FFs often perform other services outside of what is traditionally thought of as firefighting (i.e., fire suppression), for example, they provide non-fire emergency services for large-scale local events. Despite appearing to be less physically demanding than fire-related duties, it is unclear whether FFs experience heightened levels of physiological strain while providing non-fire emergency services. METHODS: 15 male FFs (M±SD; age=40±11 y, 100% white/Caucasian) were observed across 5 games while performing emergency medical services during home football games at The University of Alabama. FFs completed health and exercise history questionnaires; heart rate (HR), blood pressure (BP), and body weight were measured pre- and post-shift. FFs were assigned to a bike (n=6) or logistics (n=9) team and wore GPS-enabled monitoring systems that recorded physiological and environmental data during each shift. Analyses included descriptive statistics, independent t-tests, and bivariate correlations. RESULTS: Averaged across the 5 games, shifts lasted 8.2±1.0 h and reached temperatures of 22.8±3.0 °C. FFs were obese (based on body mass index [BMI]=33.1±6.2 kg/m2) and had stage 2 hypertension based on pre-shift resting systolic BP/diastolic BP values (142.6±14.2/85.7±29.2 mmHg). FFs assigned to the bike team were younger (MD±SD; -13.8±16.6 y, p\u3c0.001), had a lower BMI (-5.1±9.2 kg/m2, p=0.02), but achieved higher average HR (8.1%±11.5% of maximal HR, p=0.002) and training intensity (a measure of combined mechanical and cardiac load: 0.5±0.5 units, p\u3c0.001) compared to logistics. Average HR (r=0.69, p\u3c0.001), peak core temperature (r=0.57, p=0.003), and distance traveled (r=0.77, p=0.01) were positively associated with a higher training intensity. Age (r=-0.74, p\u3c=0.001) and BMI (r=-0.53, p=0.02) were negatively associated with training intensity. CONCLUSIONS: FFs presented with suboptimal cardiovascular health and experienced increased levels of physiological strain while performing non-fire emergency services. Physiological strain differed by FF assignment (bike vs. logistics), but it also appeared to be mediated by individual factors. Improving cardiovascular health should remain a top priority for the health, safety, and performance of FFs