Effectiveness of a light-weight ice-vest for body cooling in fire figther´s work

The aim of the present study was to examine the effects of wearing a light-weight ice-vest (1 kg, water) on physiological and subjective responses in fire fighter’s work. The experiments were carried out in a climatic chamber, in a container under extreme radiant heat, and during simulated smoke-diving. In addition, the physical cooling effect of the ice-vest was measured with a thermal mannequin. Four experienced fire fighters participated in the experiments. In all tests, the subjects wore the standard clothing for fire fighters with the self-contained breathing apparatus. The total extra weight carried was 21-23 kg. The ice-vest was worn over the underwear. The laboratory tests consisted of 30 minutes of treadmill walking at a moderate (4 km/h, no inclination), and a heavy (4 km/h, inclination of 4 degrees) work intensity in the heat (45 °C, 30 %) with and without the ice-vest. The results showed that the ice-vest effectively reduced skin temperatures under the vest, especially on the back under the breathing apparatus. Wearing the ice-vest did not affect the metabolic rate, skin temperatures outside the vest or the rise in rectal temperature. On average, heart rate was ca. 10 beats/min lower, amount of sweating was reduced by 13 %, and subjective sensation of effort and warmth were lower during work with the ice-vest compared to work without it. The results from tests in the container and in the smoke-diving house largely supported the laboratory results. According to the thermal mannequin tests, the useful energy available from the vest for body cooling was rather high (58 %). In conclusion, the light-weight ice-vest clearly reduces circulatory, thermal, and subjective strain during demanding smoke-diving tasks. It was estimated that the added benefit is 10-15 %. (Less)