E-14H Free Communication/Thematic Poster Physiology of Fire Fighting
There are no published studies on the responses of female fire fighters during two work bouts in the heat. The length of time a fire fighter works in a burning building depends on the air supply duration. The fire fighter then exits the building and is allowed to rehydrate and recover. After about fifteen minutes he/she reenters the fire and continues to work.
This study determined the physiological responses of female fire fighters to two similar bouts of work in a 40°C environment at 50% of their VO2max. Peak heart rates (HR), rectal temperatures (Trec), and rate of perceived exertion (RPE) were compared between two work bouts separated by a standard recovery period.
Seven female fire fighters walked for 20 minutes while dressed in complete fire fighting ensemble at 50% of their VO2max in a 40°C environment. After the first work bout (WB1), subjects removed their clothing, rehydrated and rested in front of a fan until their Trec returned to 0.5°C above pre-exercise levels. Then they completed a second work bout (WB2) similar to WB1. The recovery after WB2 was also monitored. HR, Trec, and oxygen consumption were measured throughout the experimental period.
The differences in Trec, HR and RPE between WB1 and WB2 were significantly higher during WB2: HR1=151.3 ± 16.6 bpm vs. HR2=161.6 ± 12.3 bpm, (p = 0.008), Trec1=37.79 ± 0.18°C vs. Trec2=38.16 ± 0.22°C, (p = 0.003) and RPE1=11.96 ± 1.2 vs. RPE2=12.37 ± 1.4, (p = 0.026).
Despite the rest between the two work bouts, WB2 was significantly more physiologically stressful than WB1. Consequently, the second recovery period was significantly longer than the first recovery period (duration1=12.03 ± 5.3 min vs. duration2=17.86 ± 6.8 min, p = 0.021). Supported by the Las Vegas Fire Union, Local 1285; Las Vegas Fire and Rescue Department; UNLV Graduate Student Association.