The effect of head cooling on deep body temperature and thermal comfort in man.

A liquid conditioned hood (LCH) made of stretch nylon was used to investigate the effect of head cooling on deep body temperature and thermal comfort in man. Six male subjects each performed two experiments of 2 h duration, in a climatic chamber, in conditions of dry bulb temperature 40 degrees C, wet bulb temperature 29 degrees C and 50 mm black globe temperature 50 degrees C. In one experiment head cooling was given during the first hour and in the other during the second hour. In both experiment, auditory canal (Tac) and oesophageal (Toe) temperatures increased during the first hour. During the second hour, without head cooling Tac and Toe continued to increase, whilst with head cooling no further increase in either was observed with an improvement in both head and body thermal comfort and with a small decrease in mean skin temperature.