Perspiration accompanies man 365 days a year and 24 hours a day and is a natural reaction for transporting excess heat, which is caused by activity, high ambient temperature or fever away from the body.
How much perspiration is produced depends on the degree of physical activity and genetic predisposition. During the thermo-regulative process of perspiring, perspiration is formed as a colourless and odourless secretion by more than 3 million eccrine perspiratory glands of the human body. At night healthy human beings produce around half a litre of perspiration. At around 20° C and with work that causes average exertion man can lose 6 litres of perspiration per day. At times of very high physical exertion the quantity of perspiration may well reach up to 4 litres an hour.
By supporting the thermal regulation of the human body, clothing may significantly contribute to the physiological comfort. Due to their numerous advantages, such as light weight, high durability and wear resistance, distinct easy care and fast drying, textiles made of synthetic fibres are increasingly popular. The hydrophobic behaviour of synthetic fibres, if they are unfinished, is a physiological deficit which has to be offset by high-performance hydrophilic properties to be able to produce proper functional textiles.