Physiological Responses To Simulated Shipboard Firefighting Tasks

Shipboard fires can result in injury and death, with cardiac events being the leading cause of death of on duty structural firefighters. Few data are available regarding the physiological responses to shipboard fires. PURPOSE: Determine physiologic responses of simulated shipboard firefighting tasks. METHODS: Seventeen subjects (age: 24 ± 5 y, VO2max: 44.4 ± 7.1 ml-1kg-1min-1) performed firefighting tasks until exhaustion. The tasks were performed in protective garments and breathing apparatus. After completing each task, heart rate (HR), core temperature (Tc), rating of perceived exertion (RPE), and physiological strain index (PSI) were measured. The test began with an entry walk of 80 m followed by carrying two 20 kg buckets up and down a flight of stairs. Subjects then completed a circuit of lifting, striking, and pulling tasks in an environmental chamber (40 ° C). The circuit was repeated until fatigue, or if stopping criteria was met. Data were analyzed by one way ANOVA with significance set at p ≤ 0.05. RESULTS: The number of subjects completing circuits 1 through 5 were 1, 7, 3, 5, and 1, respectively. All measured variables increased over time (p ≤ 0.01). HR, RPE and Tc were different from baseline at all following timepoints (p ≤ 0.04). PSI was different from baseline starting at circuit 2 (p < 0.01). Baseline HR was 85 ± 13 and increased to 176 ± 13 for subjects completing circuit 4 (p = <0.01). Similar changes were seen for Tc (baseline: 36.8 °C ± 0.2, circuit 4: 37.6 °C ± 0.3, p = <0.01), RPE (baseline: 1 ± 1, circuit 4: 7 ± 1, p < 0.01), and PSI (baseline: 4.0 ± 0.9, circuit 4: 7.0 ± 0.9, p < 0.01). CONCLUSIONS: Simulated shipboard firefighting tasks caused considerable tachycardia and hyperthermia among subjects completing multiple rounds of work. Future research should consider appropriate work to rest ratios to ensure firefighter safety. Supported by: Office of Naval Research N000142312829