Physical fatigue increases shipboard firefighting simulation completion time and perceived workload.

Firefighting involves physically demanding tasks performed under high heat and time pressure. While previous research reports the physical load involved, the extent to which physical fatigue impedes firefighting performance, especially in shipboard environments remains underexplored. Using a laboratory-based shipboard firefighting simulation, this study investigated how physical fatigue and heat influences time-to-completion (TTC), perceived workload, and muscular strength. Thirty participants completed the simulation in Fresh, Fatigue, and Fatigue + Heat conditions, followed by physical performance testing. Compared to Fresh, simulation TTC increased by 7.2% and 8.5% under Fatigue and Fatigue + Heat conditions respectively (p < 0.001; d = 0.62 - 0.69), with RPE increasing by 32% (Fatigue) and 46% (Fatigue + Heat) (p < 0.001; d = 1.31 - 2.39). Further, pre-simulation fatigue reduced both isometric mid-thigh pull and push-up peak forces (measured post-simulation) compared to control strength measures (p < 0.05; d = 0.18 - 0.27). This study highlights how physical fatigue hinders physical capabilities in a firefighting context.