Work Patterns Dictate Energy Demands and Thermal Strain During Wildland Firefighting

Abstract

Wildland firefighters do not induce consistently high cardiovascular and thermal strain while completing arduous work in a hot environment despite fairly high chest skin temperatures. The total energy expenditure in the current study suggests job demands are similar to those of 15 years ago, while the increased water turnover may reflect a change in drinking habits.

Effect of heat on firefighters' work performance and physiology

“…US wildfire fighters have reported high water turnover during multi-day wildfire suppression, which has allowed them to maintain their body mass across consecutive days (Cuddy et al, 2015). Australian firefighters have been observed to arrive dehydrated to the fireground, but have been able to consume enough fluids across the workday to complete their shift in a euhydrated state (Raines et al, 2012).…”

“…Descriptive field research has been conducted in firefighters performing work in various ambient conditions (Apud and Meyer, 2011;Budd et al, 1997b;Cuddy et al, 2015;Raines et al, 2015;Rodríguez-Marroyo et al, 2012;Rodríguez-Marroyo et al, 2011). However, the fact that work tasks are not standardised in the field, coupled with the lack of a control group, makes it difficult to precisely quantify the effect of heat on work performance and physiology.…”

“…Behaviourally, Australian wildland firefighters in various ambient conditions have been observed to arrive dehydrated to the fireground, yet consume adequate fluid over the course of the day to complete their shift in a euhydrated state (Raines et al, 2012). More recently, due to substantial water turnover, US wildland firefighters have been observed to maintain their body mass across three days of fire suppression (Cuddy et al, 2015). While the field data suggests that firefighters are able to self-manage their drinking behaviour and avoid excessive thermal and cardiovascular strain (Cuddy et al, 2015;Raines et al, 2012), there have also been numerous documented cases of heat-related illness and even death on the fireground (Baldwin and Hales, 2012;Cuddy and Ruby, 2011;Jackson, 2006;Karter, 2012;Smith, 2008).…”

“…More recently, due to substantial water turnover, US wildland firefighters have been observed to maintain their body mass across three days of fire suppression (Cuddy et al, 2015). While the field data suggests that firefighters are able to self-manage their drinking behaviour and avoid excessive thermal and cardiovascular strain (Cuddy et al, 2015;Raines et al, 2012), there have also been numerous documented cases of heat-related illness and even death on the fireground (Baldwin and Hales, 2012;Cuddy and Ruby, 2011;Jackson, 2006;Karter, 2012;Smith, 2008). Thus, the precise interplay between hydration, physiology, and manual-handling work output during hot conditions warrants investigation in a controlled environment.…”

Expectation of a loud alarm is not associated with changes in on-call sleep in the laboratory

“…During all wake periods, and when testing was not taking place, participants were required to remain in their bedrooms where they were permitted to watch movies, read, write, draw/paint or listen to music but were asked not to engage in any physical activity. Our aim was to keep activity to a minimum as this pattern of physical activity (sedentary interspersed by short bouts of more intense activity) is reflective real-world workplaces, particularly in firefighters, where activity across a day can significantly vary [20,21] with sedentary activity sometimes accounting for up to 74 % of the day [21].…”