Energy cost and energy sources during a simulated firefighting activity

This study aimed to 1) analyze the energy requirement ((V) over dotO(2)eq) and the contribution of the aerobic ((V) over dotO(2)ex), anaerobic alactic ((V) over dotO(2)al), and anaerobic lactic ((V) over dotO(2)la-) energy sources of a simulated intervention; 2) ascertain differences in mean (V) over dotO(2) and heart rate (HR) during firefighting tasks; and 3) verify the relationship between time of job completion and the fitness level of firefighters. Twenty Italian firefighters (age = 32 +/- 6 yr, (V) over dotO(2)peak = 43.1 +/- 4.9 mL.kg(-1).min(-1)) performed 4 consecutive tasks (i.e., child rescue; 250-m run; find an exit; 250-m run) that required a (V) over dotO(2)eq of 406.26 +/- 73.91 mL.kg(-1) ((V) over dotO(2)ex = 86 +/- 5%; (V) over dotO(2)al = 9 +/- 3%; (V) over dotO(2)la- = 5 +/- 3%). After 30 minutes, the recovery HR (108 +/- 15 beats.min(-1)) and (V) over dotO(2) (8.8 +/- 62.67mL.kg(-1).min(-1)) were higher (p < 0.0001) than basal values (HR = 66 +/- 8 beats.min(-1); (V) over dotO(2) = 4.57 +/- 1.07 mL.kg(-1).min(-1)), indicating that passive recovery is insufficient in reducing the cardiovascular and thermoregulatory strain of the previous workload. Differences (p < 0.001) between tasks emerged for mean VO(2) and HR, with a lack of significant correlation between the time of job completion and the firefighters' aerobic fitness. These findings indicate that unpredictable working conditions highly challenge expert firefighters who need adequate fitness levels to meet the requirements of their work. Practically, to enhance the fitness level of firefighters, specific interval training programs should include a wide variety of tasks requiring different intensities and decision-making strategies.