The regulation of the body temperature is controlled by the release of heat by blood vessel dilatation or constriction, muscle (shivering) and sweat gland activity. Thermal is dependent upon both environmental and individual factors and is influenced by the core and skin temperatures of the body. There are four essential conditions for person to be in state of thermal comfort; 1) the body is in heat balance; 2) sweat rate is within comfort limits; 3) mean skin temperature is within comfort limits (33-35°C); 4) local discomfort is absent. The thermoneutral zone for naked resting subjects has been defined to lie between 28-30°C (ambient temperature). In this comfort zone the human body is unaware of warmth or coolness. Outside this range the body feels discomfort. This means that the balance between the rates of heat loss and heat generated must be maintained. This is usually done by putting on or taking off clothes. However, in many situations it would be a significant advantage if the cioths could play an active role in maintaining the body within the thermal comfort zone without taking them off or on that frequently. Especially during short term changing conditions this would be of particular relevance. For instance, moving between air conditioned locations in warm climates or going in and out from stores in cold climates. Also during short term intermittent physical activity it would be advantageous if the cloths could buffer some of the energy released by the body. For instance, after a short run to the bus stop or departure gate, a cooling effect preventing start of sweating would be of interest.