Thermal underwear is a type of two piece underwear with long legs and sleeves and is mostly worn during cold weather. Thermal underwear is also called long johns or long underwear. Another name for the thermal underwear though less commonly used is long handles. Its main advantage over other traditional underwear is that a wearer can choose to wear the top, the bottom or both depending on the weather. Thermal underwear is part of the clothing type thermal wear.
There are various types of thermal underwear but the exact type called thermal underwear is made of a two layer fabric mostly wool and an artificial fiber. It may also be made of only wool especially in the United States of America. The main reason why the thermal underwear is made of two layers is to trap heat to insulate the body against cold.
The thermal underwear is very popular with outdoor event lovers especially those who participate in winter sports. It is a very effective way of keeping the body warm and does this by creating a small space of air between the body and the underwear. The thermal underwear has two layers hence creates double layers hence is warmer than ordinary under wears. This is a very positive attribute especially for winter wear.
Origin of thermal underwear
The exact origin of the name thermal underwear is not known but thermal has to do with heat. Its other name, long johns can be traced back to Derbyshire England. Lea Mills, a garments company is said to have created the garment and named it after a 19th century boxer named John Sullivan. Hence the thermal underwear came to be known as long johns. It is said the boxer used to wear the garments to the when going to boxing competitions.
Before the invention of the thermal underwear people used to wear several clothes together to creates an insulating layer. The main type of fabric those days was cotton. The main problem with cotton was that once wet it could not keep you warm any more and neither could it hold the insulating layer of air. It was only later after hydrophobic fabrics- those that don’t absorb water- were invented that such layering of clothes could really work. One such fabric is polyester. Of late other fabrics good enough for outdoor underwear have been developed. These include bergalene and teckwick.
The function of thermal underwear is mainly protective. During winter sports and other cold season outdoor activities, the body has to face adverse conditions like snow , sleet and extreme cold. The thermal underwear absorbs moisture from your skin and allows moisture from the middle layer of the thermal underwear reach the skin while still keeping it warm.
Ideally one should wear both pieces of the thermal underwear but this varies depending on just how cold the weather really is as well as the kind of activity one is engaged in. in case it is a heat generating one , you may not require to wear both pieces. (more…)