The Effect Of Exercise Induced Pre-Warming On Core Temperature During A Live Fire 'Search-and-Rescue' Task

Abstract

Professional fire-fighters usually work 24-hour shifts. Although fighting fires is one of their most important tasks, other, non-fire fighting related physically demanding activities such as practicing, workouts and maintenance, form the main part of a shift. These activities may have a warm-up effect on the fire-fighter's body temperature. This rise in core temperature may lead to a faster onset of heat stress symptoms during fire fighting. It may also shorten the maximal acceptable working time of a fire fighting task. PURPOSE: To explore the effect of exercise-induced pre-warming on the body core temperature during a fire fighting task under realistic conditions. METHODS: 8 professional fire-fighters of the Amsterdam Fire Brigade performed a standardized live fire ‘search-and-rescue’ task twice over two days. Standard turn-out gear and SCBA (Self Contained Breathing Apparatus) were used. Prior to one of both ‘search-and-rescue’ tasks the fire-fighters carried out a 20-min. weight-dependent (1.5 W.kg-1) bicycle ergometer test to provoke an exercise-induced pre-warming effect. During both testing days, core temperature was recorded using an ingestible core body temperature pill (CorTempTM, HQ Inc., USA). Performance time on the ‘search-and-rescue’ task was also recorded. RESULTS: Preliminary results show a higher mean core temperature during the combined bicycle ergometer test / ‘search-and-rescue’ task when compared to the single ‘search-and-rescue’ task (37.84 (SD=0.30) vs 37.59°C (SD=0.21)). The absolute highest core temperature was also higher during the combined test (38.38 vs 38.02°C). Preliminary results also show that the mean performance time of the ‘search-and-rescue’ task during the combined bicycle ergometer test/ ‘search-and-rescue’ task was 6.2% higher when compared to the single ‘search-and-rescue’ task. CONCLUSIONS: Moderate, non-fire fighting related exercise prior to a fire fighting task may lead to a higher core temperature during fire fighting. Consequently, earlier onset of symptoms of heat stress during a common fire fighting task may occur.