Tom Nagel1, Bridget Melton1, Wesley T. Blumenburg2, Brett L. Cross2, Greg J. Grosicki2. 1Georgia Southern University, Statesboro, GA. 2Georgia Southern University, Savannah, GA.

BACKGROUND: Cardiovascular events are the leading cause of death in firefighters, and nearly two-thirds of these deaths occur during or immediately following a fire suppression event. Arterial stiffness is an independent predictor of cardiovascular-specific and all-cause mortality that may be increased by a fire attack. PURPOSE: To characterize changes in central arterial stiffness, indexed as carotid-femoral pulse wave velocity (cf-PWV), and peripheral arterial stiffness, indexed as Augmentation Index (AIx), following a simulated fire attack. METHODS: Twenty-one male career firefighters (35±8 yrs; 31±5 kg/m2) reported to the testing facility in a fasted state during morning hours. After 10 minutes of supine rest, blood pressure was assessed via a brachial cuff and AIx and cf-PWV were determined via pulse waveform analysis and carotid applanation tonometry, respectively. Firefighters then participated in a seven-station simulated fire attack for time, and heart rate was continuously monitored via wireless telemetry. Brachial blood pressure, AIx, and cf-PWV were reacquired immediately upon completion. Paired t-tests were used to compare pre-post changes in blood pressure and arterial stiffness indices, and Pearson’s correlations were used to explore predictors of arterial stiffness responses. RESULTS: Average heart rate during the simulated fire attack was 164±13 bpm, and average time to completion, a surrogate for fitness, was 8.7±1.7 min. Despite significant increases (p<0.01) in mean arterial pressure (94±9 vs. 115±10 mmHG) following the simulated fire attack, cf-PWV (7.6±1.0 vs. 7.8±0.9 m/s; p=0.34) and AIx (13.8±8.6 vs. 13.9±12.3 %; p=0.98) were unaltered. Pearson’s correlations demonstrated that fire attack completion time was inversely associated with changes in cf-PWV (r=-0.53, p=0.01) but not AIx (r=-0.13, p=0.56). CONCLUSIONS: No changes in central or peripheral indices of arterial stiffness were observed following a short-duration, high-intensity simulated fire attack in male career firefighters. The observed association between fitness, indexed as fire attack completion time, and changes in cf-PWV may be explained by intensity-dependent arterial stiffness responses, whereby increases in arterial stiffness in fitter firefighters may be attributed to an ability to perform the task at a greater relative intensity.

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