Title

EVALUATION OF THREE WILDLAND FIREFIGHTER UNIFORMS DURING THREE HOURS OF WORK IN THE HEAT

Presenter Information

Kristina Pattison

Presentation Type

Presentation

Abstract

Wildland firefighters (WLFFs) wear fire-resistant uniforms, which differ between fire agencies in layers required. Efficient body-heat dissipation is important for the safety and performance of WLFFs who work arduously in hot environments where hyperthermia leads to exhaustion. PURPOSE: Evaluation of thermoregulatory effects between three WLFF uniforms during work in the heat. METHODS: Nine males (24.6 ±4.1 years, 190.0 ±17.1 cm, 81.0 ±7.9 kg, 11.2 ±3.5 %body fat, 57.4 ±5.4 ml•kg-1•min-1 VO2) completed three separate, three-hour trials of treadmill walking (3 mph, 4% grade) in a heat chamber (37 ± .05°C), with a 10-minute rest period each hour. During each trial, subjects wore different uniforms (Kevlar impregnated Nomex [FSI], Nomex [FSII], and double-layered Nomex [CF]). Variables measured were skin and core temperatures, heart rate, sweat rate, thermal comfort, and rating of perceived exertion. Physiological strain index (PSI), rate of core temperature rise, and body weight changes were calculated. Results were analyzed using a Repeated Measures ANOVA; significance was set at 0.05. RESULTS: No significant differences were found in heart rate, weight change, or skin temperatures. PSI was significantly lower for FSI than CF (p=.038), while FSII trended to be lower (p=.070). Core temperatures were significantly lower during FSI and FSII than CF (p=0.003, p=.044 respectively). CF showed significantly higher rates of core temperature rise (FSI p=0.001, FSII p=0.005). CONCLUSION: Increased uniform layers worn in hot environments result in increased physiological strain. Agencies requiring double layers would benefit from decreasing clothing layers to avoid physiological strain increases and decreases in work performance.

Category

Life Sciences

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Apr 15th, 2:00 PM Apr 15th, 2:20 PM

EVALUATION OF THREE WILDLAND FIREFIGHTER UNIFORMS DURING THREE HOURS OF WORK IN THE HEAT

UC 331

Wildland firefighters (WLFFs) wear fire-resistant uniforms, which differ between fire agencies in layers required. Efficient body-heat dissipation is important for the safety and performance of WLFFs who work arduously in hot environments where hyperthermia leads to exhaustion. PURPOSE: Evaluation of thermoregulatory effects between three WLFF uniforms during work in the heat. METHODS: Nine males (24.6 ±4.1 years, 190.0 ±17.1 cm, 81.0 ±7.9 kg, 11.2 ±3.5 %body fat, 57.4 ±5.4 ml•kg-1•min-1 VO2) completed three separate, three-hour trials of treadmill walking (3 mph, 4% grade) in a heat chamber (37 ± .05°C), with a 10-minute rest period each hour. During each trial, subjects wore different uniforms (Kevlar impregnated Nomex [FSI], Nomex [FSII], and double-layered Nomex [CF]). Variables measured were skin and core temperatures, heart rate, sweat rate, thermal comfort, and rating of perceived exertion. Physiological strain index (PSI), rate of core temperature rise, and body weight changes were calculated. Results were analyzed using a Repeated Measures ANOVA; significance was set at 0.05. RESULTS: No significant differences were found in heart rate, weight change, or skin temperatures. PSI was significantly lower for FSI than CF (p=.038), while FSII trended to be lower (p=.070). Core temperatures were significantly lower during FSI and FSII than CF (p=0.003, p=.044 respectively). CF showed significantly higher rates of core temperature rise (FSI p=0.001, FSII p=0.005). CONCLUSION: Increased uniform layers worn in hot environments result in increased physiological strain. Agencies requiring double layers would benefit from decreasing clothing layers to avoid physiological strain increases and decreases in work performance.