Sleep Restriction during Simulated Wildfire Suppression: Effect on Physical Task Performance

Abstract

ObjectivesTo examine the effects of sleep restriction on firefighters’ physical task performance during simulated wildfire suppression.MethodsThirty-five firefighters were matched and randomly allocated to either a control condition (8-hour sleep opportunity, n = 18) or a sleep restricted condition (4-hour sleep opportunity, n = 17). Performance on physical work tasks was evaluated across three days. In addition, heart rate, core temperature, and worker activity were measured continuously. Rate of perceived and exertion and effort sensation were evaluated during the physical work periods.ResultsThere were no differences between the sleep-restricted and control groups in firefighters’ task performance, heart rate, core temperature, or perceptual responses during self-paced simulated firefighting work tasks. However, the sleep-restricted group were less active during periods of non-physical work compared to the control group.ConclusionsUnder self-paced work conditions, 4 h of sleep restriction did not adversely affect firefighters’ performance on physical work tasks. However, the sleep-restricted group were less physically active throughout the simulation. This may indicate that sleep-restricted participants adapted their behaviour to conserve effort during rest periods, to subsequently ensure they were able to maintain performance during the firefighter work tasks. This work contributes new knowledge to inform fire agencies of firefighters’ operational capabilities when their sleep is restricted during multi-day wildfire events. The work also highlights the need for further research to explore how sleep restriction affects physical performance during tasks of varying duration, intensity, and complexity.

Novel Tools in Determining the Physiological Demands and Nutritional Practices of Ontario FireRangers during Fire Deployments

“…A total of 12 participants wore the ActiSleep monitor on 152 nights throughout the 2014 fire season, and average TST regardless of deployment type was found to be 364 ± 61.2min/night (~6 ± 1hrs/night). This finding is consistent with the TST observed in Australian Rangers during deployments [55,56]. Accordingly, 6hrs/night was used for daily energy expenditure estimation by multiplying this value by the corresponding Compendium of Physical Activities value for sleeping (1.0METs) [54].…”

“…While FireRangers are still required to perform physical labour while working at the base, in preparation for fire deployments, our findings indicate that these workers have an opportunity to rest and recover from the intense physical demands of fire suppression activities while they await subsequent fire deployments. Other research on Australian FireRangers has indicated that they are able to self-regulate their daily physical activity in order to maintain task performance and subjective measures of exertion over consecutive days performing fire suppression tasks [56,67]. This research indicates that FireRangers exhibit “activity synergy”.…”

The Impact of Shiftwork on Skeletal Muscle Health

“…Indeed, in a highly competitive team weight-lifting environment, Blumert et al [100] found that maximal strength is not impaired by 24 h of complete sleep deprivation. We have also shown that firefighters working in teams will maintain their physical performance on important tasks without a decrease in motivation or perceived exertion [101]. Neither of these acute sleep restriction or deprivation environments are a true proxy for the chronic sleep disruptions commonplace for shiftworkers.…”

Relationships between inflammatory cytokine and cortisol responses in firefighters exposed to simulated wildfire suppression work and sleep restriction

“…The physical work circuit comprised six simulated wildland firefighting tasks designed to mimic the physical demands involved in Australian wildfire suppression work (Ferguson et al 2011;Phillips et al 2012;Vincent et al 2015). A job task analysis was used to design the firefighting work circuit.…”

“…The tasks included lateral repositioning of a hose, rake hoe work, hose rolling, charged hose advance, black out hose work, and static hold of a hose. The performance of each physical task (i.e., repetitions completed for each task within each work period) was self-paced and completed in a predetermined order with work-to-rest ratios designed to mimic the performance of these tasks on the fire-ground (Ferguson et al 2011;Phillips et al 2015;Vincent et al 2015).…”