Physiological strains in hot-humid conditions while wearing disposable protective clothing commonly used by the asbestos removal industry

摘要

The purpose of this study is to investigate workers' responses to work in hot-humid conditions while wearing protective clothing commonly used by the asbestos removal industry, and to evaluate the effects of resting between work bouts in a cool environment on the physiological strain. Seven male students wearing impermeable protective clothing and air masks were exposed to the following conditions for 100 min on separate days: (1) hot conditions (35#xB0;C/85RH), (2) cool conditions (20#xB0;C/85RH), and (3) hot/cool conditions (working in hot conditions and resting in cool conditions). After 12 min rest, the subjects worked on an ergometer (70 Watts) for 18 min. This experimental schedule was repeated three times under each environmental condition. Rectal temperature (T#x3C0;), heart rate (HR), sweat rate (SR) and discomfort sensation were recorded. Two of the subjects were not able to complete the experiment in hot conditions. The increases in T#x3C0;and HR with time were not found in cool conditions. Although T#x3C0;increased in hot/cool conditions, it was almost half of that in hot conditions. Since HR did not return to the pre-work level during recovery in hot conditions, HR during work was accompanied by increases in HR at pre-work. HR during work in hot/cool conditions was higher than that in cool conditions, HR at pre-work, however, was almost the same as that in cool conditions because of rapid recovery. The means of SR in hot and hot/cool conditions were five and four times greater than that in cool conditions, respectively. Discomfort sensation was improved by resting in cool conditions either at rest in cool conditions or during work in hot conditions. The rate of body heat storage that was calculated at the end of each work and recovery period showed that it was positive even in recovery under the hot conditions. It also presented a significant negative phase in recovery under the hot/cool conditions. Thermal stress was linked to work in protective clothing in hot-humid environments. However, the physiological strains were dramatically ameliorated by resting between work periods in a cool environment. The idea of a #x2018;cool room#x2019; inside the workplace, so to reduce thermal stress, is proposed.