Sensations of temperature and humidity during alternative work/rest and the influence of underwear knit structure

The purpose of this study was to evaluate the influence of alternate work/rest and knit structure of underwear on various subjective sensations of temperature and humidity. Underwear manufactured from 100% polypropylene fibres in five different knit structures (1-by-l rib, fleece, fishnet, interlock, double-layer rib) were applied and tested as part of a prototype clothing system. Human testing was done on eight male subjects, and took place at T_a = 5°C, T_dp = - 3·5°C and V_a = 0·32ms^-1. The test comprized a twice-repeated bout of 40 min cycle exercise (56 Wm^-2;. [Vdot]O₂ = 1741O₂min^-1˜52±4·9% V O₂ max) followed by 20 min of rest (OWm^-2 0·351 O₂ min^-1). Alternate work/rest had a significant influence on all temperature and humidity sensations of the body, of the skin-clothing interface, and of the environment. Knit structures of the underwear influenced sensations of humidity significantly, but not sensations of temperature. The various sensations of temperature correlated best with core temperature, whereas the sensations of humidity correlated with skin wettedness. Subjective sensations of wetness of the skin and of the clothing are recommended as a sensitive tool to discriminate between the thermal function of similar garments.