Maximal Oxygen Consumption In Professional Firefighters Across Position And Gender

Abstract

PURPOSE The present study was undertaken as part of a national Fire Act Grant award to determine 1) the cardiorespiratory fitness of professional male and female firefighters prior to entry into a 1-yr exercise training program, and 2) if differences in cardiorespiratory fitness exist between the various firefighting positions within a company. METHODS After appropriate risk factor stratification, 363 professional firefighters (males n=355, females n=8) underwent maximal graded metabolic exercise testing with (moderate risk, n=199, high risk, n=11) or without (low risk, n=153) physician supervision and 12-lead electrocardiography. Of the 210 “at risk” subjects, 36 subjects were dropped from data analysis because of significant ST-segment changes (n=27) or ventricular ectopy (n=9). In addition, 17 additional tests were dropped from data analysis as they did not achieve maximal effort criteria. Therefore, VO2max was directly measured on the treadmill via open-circuit spirometry for 310 firefighters (males, n=302; females, n=8) using either a standard Bruce (n=53) or a modified Bruce (n=257) protocol in which the stage durations were reduced to 2 min. RESULTS Values are reported as mean ± SEM. There were no significant differences in VO2max between males and females (Males=38.37 ± 0.42 ml ± kg−1 ± min−1; Females=34.86 ± 2.92 ml·kg−1·min−1). When comparisons of VO2max were made by firefighter position (Captain, n=81; Driver, n=70; Firefighter, n=133; Administrator, n=26) with age held as a covariate, there were no significant differences amongst the positions (Captain = 38.73 ± 0.71 ml·kg−1·min−1; Driver=38.39 ± 0.77 ml·kg−1·min−1m; Firefighter=38.08 ± 0.58 ml·kg−1·min−1; Administrator=37.63 ± 1.34 ml·kg−1 ± min−1). CONCLUSIONS Mean VO2max values for professional firefighters across positions are similar when differences due to age are removed. Furthermore, the mean values for both males and females for VO2max are above the minimal threshold shown to be associated with an increased risk of performance failure due to fatigue. However, 22.9% (Captain, n=17; Driver, n=18; Firefighter, n=36) of the firefighters who actively fight fire had VO2max values below the minimum performance threshold. Thus, an exercise training intervention designed to improve cardiorespiratory endurance is warranted to reduce the likelihood of performance failure due to fatigue. Supported by the Department of Homeland Security: Assistance to Fire Fighters Grant Program “MFRD Firefighter Health & Wellness Program”