Underclothing and its Physiological Effects in a Hot-Dry Environment.

摘要

When underclothing of any type is worn, data collected using a static, copper manikin clearly indicate a slightly increased insulation and decreased evaporative transfer. In order to assess air movement in the dynamic state ('pumping'), the present study involved 8 men (21.2 yr., 175.2 cm and 69.1 kg) to evaluate 4 underclothing systems worn under a desert uniform: (1) no underwear; (2) std boxer shorts and t-shirt; (3) fish net 'Brynje'; and (4) ladder net 'Brynje'. The physiological trial was designed using the copper man data to select an environment and work combination which would maximize the physiologic differences expected. Accordingly, each subject walked at 4.8 km/hr with each system (40 min walk, 20 min rest and 40 min walk) at 49 C, 20% R.H. Test results show that: (1) No underwear resulted in significantly cooler mean weighted skin temperature at minutes 60, 80, and 100; (2) Rectal temperature was slightly lower at a given time interval with no underwear; (3) There was a rise in heart rate during the work periods, but no differences among underwear systems; (4) Sweat production showed no differences; and (5) The ratio of evaporated/produced sweat showed that no underwear allowed better evaporative cooling than any of the other systems. Neither fish- nor ladder-net underwear appear to offer any advantage over regular underwear; subjective comfort ratings support these conclusions.