title: Simulated Firefighting Task Performance and Physiology Under Very Hot Conditions.
abstract: OBJECTIVE
  To assess the impact of very hot (45°C) conditions on the performance of, and physiological responses to, a simulated firefighting manual-handling task compared to the same work in a temperate environment (18°C).
  
  
  METHODS
  Ten male volunteer firefighters performed a 3-h protocol in both 18°C (CON) and 45°C (VH). Participants intermittently performed 12 × 1-min bouts of raking, 6 × 8-min bouts of low-intensity stepping, and 6 × 20-min rest periods. The area cleared during the raking task determined work performance. Core temperature, skin temperature, and heart rate were measured continuously. Participants also periodically rated their perceived exertion (RPE) and thermal sensation. Firefighters consumed water ad libitum. Urine specific gravity (USG) and changes in body mass determined hydration status.
  
  
  RESULTS
  Firefighters raked 19% less debris during the VH condition. Core and skin temperature were 0.99 ± 0.20 and 5.45 ± 0.53°C higher, respectively, during the VH trial, and heart rate was 14-36 beats.min(-1) higher in the VH trial. Firefighters consumed 2950 ± 1034 mL of water in the VH condition, compared to 1290 ± 525 in the CON trial. Sweat losses were higher in the VH (1886 ± 474 mL) compared to the CON trial (462 ± 392 mL), though both groups were hydrated upon protocol completion (USG < 1.020). Participants' average RPE was higher in the VH (15.6 ± 0.9) compared to the CON trial (12.6 ± 0.9). Similarly, the firefighers' thermal sensation scores were significantly higher in the VH (6.4 ± 0.5) compared to the CON trial (4.4 ± 0.4).
  
  
  CONCLUSIONS
  Despite the decreased work output and aggressive fluid replacement observed in the VH trial, firefighters' experienced increases in thermal stress, and exertion. Fire agencies should prioritize the health and safety of fire personnel in very hot temperatures, and consider the impact of reduced productivity on fire suppression efforts.
authors.affiliation: School of Exercise and Nutrition Sciences, Faculty of Health, Deakin University Melbourne, VIC, Australia.
authors.forename: Brianna
authors.initials: B
authors.lastname: Larsen
authors.affiliation: School of Exercise and Nutrition Sciences, Faculty of Health, Deakin University Melbourne, VIC, Australia ; Centre for Physical Activity and Nutrition Research, Faculty of Health, Deakin University Melbourne, VIC, Australia.
authors.forename: Rod
authors.initials: R
authors.lastname: Snow
authors.affiliation: Faculty of Health Sciences, University of Ontario Institute of Technology Oshawa, ON, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Williams-Bell
authors.affiliation: School of Exercise and Nutrition Sciences, Faculty of Health, Deakin University Melbourne, VIC, Australia ; Centre for Physical Activity and Nutrition Research, Faculty of Health, Deakin University Melbourne, VIC, Australia.
authors.forename: Brad
authors.initials: B
authors.lastname: Aisbett
keywords: exertion; heat; hydration; thermal stress; work output