Physiologic responses of firefighter recruits during a supervised live-fire work performance test.

The aim of this research was to determine physiologic responses to typical activities of military Italian firefighters. Heart rate (HR), metabolic equivalent units (MET), skin temperature ( T.Sk.), and galvanic skin response (GSR) were measured in 13 firefighters (age = 36.3 +/- 6.9 yr; period of military fire service = 16.8 +/- 7 yr) during the acclimation phase (5 min standing, still dressed in their protective clothing), the work phase (simulated firefighting situations), and the following 24 hours. Multivariate linear step-wise regression showed that body mass index was highly correlated with mean and minimal HR values during the acclimation phase (beta 0.59, p < 0.001; beta 1.90, p = 0.003) and with mean and maximum HR values during the work phase (beta 1.08, p = 0.05; beta 1.17, p = 0.04), increasing cardiovascular stress. Firefighting tasks were associated with high energy expenditure. The minimum and mean MET values, during the acclimation phase, were significantly correlated with age (beta 0.49, p = 0.008 and beta 0.46, p < 0.01). During the work phase, maximal MET values were also strongly correlated with weight (beta 0.51, p = 0.03). No correlations between predictor and dependent variables were found for GSR; however, the high GSR levels recorded during the work phase returned to normal values only 12 hours after completion of the work phase, indicating that high levels of psychological stress remain, even after physical recovery. The data obtained in this study demonstrate that the physical fitness and anthropometric characteristics of firefighters influence the performance of firefighting tasks. These results may be useful to set up specific training that meets the real needs of firefighters in terms of physical fitness.