Exposure to smoke and high temperatures, coupled with little sleep, can impair firefighters’ performance on the fireground. This research investigated the combined effects of these three stressors on firefighters during suppression.
The project, nicknamed ‘Awake, Smoky and Hot’, was led by Professor Sally Ferguson, CQUniversity, and Dr Brad Aisbett, Deakin University, and also involved researcher Dr Bradley Smith from CQUniversity.
A three-day and four-night bushfire suppression laboratory simulation was developed to look at the effects of smoke, heat and fatigue in various combinations on a firefighter's work performance. End user engagement ensured that the simulation created realistic physical and cognitive workloads, as well as crew scheduling and activities. This was combined with sufficient researcher control to enable conditions to be repeated across groups at different research sites. More than 90 rural firefighters (83% volunteer, 17% career) volunteered to participate.
Participants lived in a simulated environment for the duration of the study (including physical tasks, rest breaks, meals, and sleeping). During the daytime, participants adhered to a strict schedule, completing 14 two-hour testing sessions over four days. Each session consisted of 50 minutes of physical work designed to mimic fireground tasks, followed by physiological testing lasting 20 minutes and a cognitive test for 20 minutes. Testing sessions were completed in full protective clothing. Sleep deprivation conditions involved sleeping four hours per night, while exposure to heat and carbon monoxide was varied.
Findings show that there was no adverse impact of consecutive nights of moderate sleep restriction on physical work, physiology or perceived exertion performed in either temperate or hot conditions. Firefighters offset the adverse impact of high temperatures on their physical work by increasing their fluid intake before and during their work in hot conditions.
The study also found that shortened sleep in hotter temperatures was associated with less ‘deep’ sleep, compared to sleep in milder temperatures. When fatigued through shortened sleep, firefighters could identify their performance was declining, but could not identify the degree of their impairment.
The findings are significant step forward in the available evidence-base that agencies can use to promote and preserve the operational readiness of their personnel.
Several PhD students from Deakin University were involved with this project. Cara Lord worked on developing a prototype physical selection test for tanker-based firefighters. Alex Wolkow focused on sleep deprivation and stress responses, and whether emergency work could have a negative impact on health.
Brianna Larsen evaluated the effect of extreme temperature on a firefighter’s work performance and physiology, by simulating firefighting tasks in a climate chamber. Grace Vincent investigated firefighters’ sleep quantity and quality during multi-day bushfire suppression. Inadequate sleep increases the likelihood of impaired performance, which can result in higher error and incident rates, impacting both safety and efficiency.