EFFECTS OF MOISTURE ABSORPTION BY CLOTHING ON THERMAL RESPONSES DURING INTERMITTENT EXERCISE AT 24-DEGREES-C

The effects of two kinds of clothing with different properties with re spect to moisture absorption on thermophysiological responses and puls e rate were studied during intermittent exercise at an ambient tempera ture (T-a) of 24 degrees C. The two kinds of clothing ensemble tested were cotton T-shirt with short sleeves and cotton long-sleeved working dress with full-length trousers (C), and polyester T-shirt with short sleeves and polyester long-sleeved working dress with full-length tro users (C), the thermal resistances of which were nearly equal. Five wo men aged 21-32 years, served as subjects. The environmental conditions were 24 degrees C T-a, 50% relative humidity and 0.14 m . s(-1) air v elocity. The subjects, wearing either C or P, exercised for 10-min on a cycle ergometer at an intensity of 30% maximal oxygen uptake and the n 10-min rest. This sequence was repeated four times. Rectal and skin temperatures at several sites, local sweating rate, pulse rate and clo thing microclimates were continuously compared between C and P through out the experiment. The major findings were firstly, rectal temperatur e rose significantly higher in P; secondly, pulse rate was higher in P both during exercise and rest; thirdly, clothing surface temperature on the back rose highly significantly during the fourth exercise perio d and then fell significantly during the fourth rest period in C; and fourthly, four out of five subjects felt wetter in P during the latter half of the experiment. These results are discussed from the viewpoin t that the reduced thermal insulation due to the absorption of moistur e in C accelerated dry heat loss, resulting in an inhibition of the in creases in core temperature and pulse rate.