A field survey of thermal stress in New Guinea villagers

Abstract

A survey to assess the thermal stress experienced by New Guinea villagers during everyday life was conducted on about 30 adults of each sex at each of two places - the villages of Kaul, on Karkar Island, and Lufa in the highlands. An observer accompanied each subject throughout the day, continuously recording his activity, his adjustments of clothing, and the time he spent in sunshine and in shade. Every 20 min, measurements of air temperature, humidity, and wind speed, and the mean radiant temperature in sunshine and shade, were made near the subject. Air temperature in the villagers’ houses was continuously recorded by thermograph. A preliminary analysis of the results indicates that people at Lufa were exposed to lower air temperature, humidity, and wind speed, but greater radiant heat, than those at Kaul. The average thermal stress, as calculated by the method of Belding & Hatch, was only slightly less at Lufa than at Kaul. At Kaul the air temperature indoors was much the same as that outdoors, but at Lufa it was 2 °C higher than outdoors. Air temperature and mean radiant temperature at Kaul were considerably higher in houses built of galvanized iron than in those of traditional bush materials. Men working in a copra drier were intermittently exposed to air temperatures over 71 °C, and to globe-thermometer temperatures as high as 110 °C. Kaul people engaged in their normal pursuits were found to lose an average of 2196 g of sweat in 7.5 h and to replace about half of it by drinking, thus incurring a fluid deficit of 1172 g, equivalent to 2.1 % of body mass.