Thermophysiological effects of two different types of clothing under warm temperatures

This paper is aimed to investigate which part of the body should be uncovered by clothing for the heat stress to be lessened under the influence of an ambient temperature increase from 32 degrees C to 40 degrees C. Two types of clothing were used as experimental garments: one was turtle necklined sports jacket with short sleeves and short pants (HALF) and the other was open round necklined sports jackets with long sleeves and short pants (OPEN). Both types of clothing were made of 100% vinyl. Uncovered area was same between HALF and OPEN. Five males volunteered as subjects. The subjects wearing either HALF or OPEN sat quietly in a bioclimatic chamber for 160 min, where ambient temperature (Ta) was gradually increased from 32 degrees C to 40 degrees C by 2 degrees C every 30 min with a relative humidity of 40%. Thermophysiological parameters such as esophageal temperature (Tes), tympanic temperature (Tty), local sweat rate, skin temperatures at 11 sites and evaporation were continuously measured. Main findings are as follows: 1) Tty was kept lower significantly in HALF than in OPEN during warm exposure. 2) An increase of local sweat rate was significantly lower in HALF. 3) Skin temperature at abdomen region was kept lower significantly in HALF, reflecting lower core temperature in HALF. It is concluded that HALF seems more beneficial than OPEN in reducing heat strain during warm exposure, due to more effective cooling by evaporation from the uncovered forearms (HALF) than from the uncovered upper trunk (OPEN).