PHYSIOLOGICAL-RESPONSES OF MEN WORKING IN FIRE FIGHTING EQUIPMENT IN THE HEAT

On three separate occasions, 11 well conditioned fire fighters were tested on a treadmill at 40 km h−1 on a 10% grade for 15 min. The first two tests were conducted in the laboratory and the third test was carried out in a sauna. During the first test (BL), subjects wore the normal lightweight, ‘blue’ uniform. For the other two tests (TL, TS) they wore fire-fighting ‘turnout’ uniforms, boots and breathing apparatus. After 15 min of exercise, heart rates increased significantly forcach trial (BL 99·2±3·3, TL 136·4 ± 4·3 and TS 172·7 ± 3·2 beats min −1 as did mean skin and rectal temperatures. Oxygen uptake values were similar for tests in turnouts (TL 10·47 ± 0·75 and TS ·mn; 0·59 cm3 kg−1 min−1). Both these mean values were significantly higher than that obtained for trials in blues (BL 7·13± 041 cm3 kg−1 min−1). There were also significant differences between weight loss, breathing rate and plasma volume changes. Collectively these data show that the additional weight and insulating properties of fire fighting equipment impose significant stress on fire fighters, especially while working in the heat. These data also help to explain, in part, the extremely high heart rates for prolonged periods previously observed during actual fire fighting. © 1979 Taylor & Francis Group, LLC.