The human body functions optimally at its ideal temperature of 37°C. It consumes the least energy, and is effective and durable. To guarantee this optimal temperature even in hot environments, nature provided man with a highly efficient air conditioning system: sweat. Sweat is too precious to dispose of completely. Our skin needs moisture to cool itself down. Moisture must first evaporate on the skin before our body temperature can be reduced. Traditional active undergarments don’t take this into account. They absorb moisture completely and keep the skin as dry as possible. A mistake. Dry skin feels good, but it doesn’t cool. Modern functional underwear supports this natural air conditioning system, harnessing the cooling function of the sweat film instead of getting rid of it.