Psychological, Physical, and Heat Stress Indicators Prior to and after a 15-Minute Structural Firefighting Task

Abstract

Firefighters work in strenuous conditions for prolonged periods wearing up to 20 kg of personal protective equipment. This often contributes to significant heat and cardiovascular strain. This study examined the relationships between psychological and physical measures taken prior to undertaking a 15 min firefighting task, and the occurrence of heat stress and high levels of fatigue following the task. Nine qualified firefighters completed a 15 min “live burn” scenario designed to mimic a fire started by a two-seater couch in a lounge room and completed simulated tasks throughout the duration. Logical reasoning, speed and accuracy, general motivation and fatigue, and physical and mental effort were recorded pre-scenario, and at 0- and 20-min post-scenario. General motivation and fatigue scores at 0- and 20-min post-scenario were highly correlated with each other (rs = 0.90; p = 0.001). The general motivation and fatigue scores, at 0- and 20-min post-scenario, were also strongly related to pre-task logic/reasoning test scores (Post 0 rs = −0.77, p = 0.016; Post 20 rs = −0.87, p = 0.002). Firefighters with lower logical reasoning and speed and accuracy scores were more susceptible to fatigue and impaired cognition when exposed to rises in core temperature and heat stress.

Do extreme temperatures affect cognition? A short review of the impact of acute heat stress on cognitive performance of firefighters

“…This review summarized seven research studies that measured cognitive functioning before and after firefighters completed a training exercise in high temperatures. Two studies showed improvements ( Greenlee et al, 2014 ; Walker et al, 2015 ), three showed impairments ( Hemmatjo et al, 2017 ; Zare et al, 2018 ; Hemmatjo et al, 2020 ), and two showed no effect of heat ( Abrard et al, 2021 ; Canetti et al, 2022 ).…”

“…Using a cognitive test from the Mini Mental State examination (Folstein et al, 1975) requiring participants to count backwards from 100 by 6, 7, or 8 they found no difference in performance pre-and post-exercise. Canetti et al (2022) also measured cognition before and after a live container fire exercise (temperatures exceeded 400°C) and found no differences. They assessed cognition with three tests; a digit cancelation task in which participants had 90-s to cross out targets on a sheet of paper, a logical reasoning task in which they had 30-s to answer true or false to statements about letter pairings (see Baddeley, 1968), and a recall task in which they were presented with items for 30-s and had to recall as many as possible.…”

Potential impact of metabolic syndrome on cognitive function in US firefighters

“…In the course of their work, firefighters are exposed to several negative environmental factors, including heat exhaustion and toxic hazards, which can result in negative effects on neuro-cognitive function ( 35 ). Canetti et al investigated the effect of a simulated 15-min firefighting task on psychological and heat stress indicators in firefighters ( 36 ). The author confirmed that cognitive function was impaired due to exposure to elevated heat stress and core temperature during simulated firefighter duties.…”

Overexertion and heat stress in the fire service: a new conceptual framework

“…20,21 Additionally, elevated core temperature and heat stress could cause greater fatigue and lower cognitive function in some firefighters. 22 Mitigating physiological and thermoregulatory strain is critical to prevent overexertion and musculoskeletal injury which represent the leading cause of lost-time duty in firefighters 20,21…”

“…Combining the effects of exercise and heat impairs firefighter‐specific functional balance and increases the likelihood of slips, trips, and falls, which lead to musculoskeletal injuries 20,21 . Additionally, elevated core temperature and heat stress could cause greater fatigue and lower cognitive function in some firefighters 22 . Mitigating physiological and thermoregulatory strain is critical to prevent overexertion and musculoskeletal injury which represent the leading cause of lost‐time duty in firefighters 20,21 …”