Thermal responses to light, moderate and heavy daily outdoor work in cold weather.

Working in the cold is part of the normal routine in outdoor occupations in winter in the subarctic regions, but there are few data available on occupational exposure to cold during outdoor work. In the present study, thermal responses were measured in winter in Finland during 23 working days among young, healthy men working in heavy, moderate and light daily outdoor jobs. During the measurements ambient temperature ranged from +3 to -27 degrees C, air velocity from 0.2 to 4.3 m.s-1, and the subjects wore normal winter clothing. The skin temperatures measured often indicated disturbed performance, discomfort and a risk of adverse health effects, especially during the very cold days (ambient temperature less than -15 degrees C) in the light work. The most common problems were cooling of the extremities and the face and cool or cold sensations. The temperatures on the distal parts of the upper extremities correlated significantly with the heaviness of the work (r = 0.51, P = 0.014). The core temperature remained at the safety level in each case. Apart from clothing, an appropriate work load proved to be an effective way of keeping up the temperature of the extremities in cold work, and that should be taken into account when outdoor work is being planned.