Loss of Acclimatization After Six Days of Work in Cool Conditions on the Surface of a Mine

¹ From the Applied Physiology Laboratory, Transvaal and Orange Free State Chamber of Mines, and the Personnel Department, Anglo-American Corporation of South Africa, Ltd., Johannesburg, South Africa

Seventy-three men were acclimatized to work in an area of a mine with a wet bulb temperature of 91°F. They then spent 6 days on the surface of a mine in relatively cool conditions. On return to work in the hot area mouth temperature was significantly increased, viz., a mean increase of 0.7°F. One further day of work in heat decreased mouth temperature significantly, viz., the increase following cool exposure fell from a mean of 0.7°F to 0.2°F. The logical step therefore when large groups of men are required to work in heat is always to expose them to 1 or 2 days of work in heat if they are moved to cool conditions, for any reason, for 6 or more days.