"Which sweater to choose in the cold: knitted or fleece"

The aim of the present study was to investigate the influence of two common wool sweaters in a clothing ensemble on sweat production, sweat accumulation and sweat distribution in the clothing ensemble, as well as on other thermoregulatory responses together with comfort of man. A further aim was to investigate the influence of the two different sweaters on the temperature and the humidity gradient through the clothing ensemble in order to describe the different avenues and forms of heat exchange. Thick woolen middle layer sweaters manufactured in two different constructions, fleece and knitted, were tested as part of a 3-layer clothing system. The test was performed on eight male subjects (Ta = 10 degrees C, RH = 85%, Va < 0.1 m/s), and comprised a twice repeated bout of 40-min cycle exercise followed by 20 min rest. Skin temperatures, rectal temperature, weight loss and humidity near the skin and in the clothing layers were recorded during the test. Total changes in body and clothing weight were measured separately. Furthermore, subjective ratings on thermal comfort and on sensation of temperature and humidity were collected. The results demonstrated that there were no significant physiological and subjective differences when the two sweaters were worn, apart from higher sweat production and accumulation when the knitted sweater was used. It is assumed that this is a result of a larger thickness rather than different construction. Choosing the knitted sweater or the fleece wool sweater for work in an ambient temperature of 10 degrees C will be of minimal significance in practice. However, a sweater with more sweat accumulated will be heavier and this reduces the air layer between the garments, decreasing the clothing ensemble's insulation value.