Winter Underwear - The Base Layer (Foundation)
Arctic, Antarctic, Cold Weather, Winter Clothing

The base layer is the layer next to the skin, usually thought of as being underwear, or in cold climates, "thermal" underwear. Despite cold temperatures, perspiration is still a problem, in fact it can be more so than in a temperate climate. The body loses moisture at almost all times whether undergoing any great level of exertion or not. If there are numerous insulating layers keeping you warm, then it is more difficult for the perspiration to be able to escape. If the perspiration is not removed it will result in the wearer becoming uncomfortable and a feeling of "clamminess" as well as decreasing the efficiency of the insulating layers.

Underwear that is able to wick this moisture away from the skin surface therefore becomes more important and this is an important factor in choosing garments. Modern "thermals" are made of synthetic fibers such and polypropylene or "fleece" that have good insulating properties and are also able to efficiently wick moisture away from the skin. Zips at the neck or even full length can help regulate temperature

In selecting clothing for cold and extreme weather the priorities are:

• keep the body warm, particularly fingers and toes
• allow for free removal of perspiration
• allow free movement
• be comfortable at all times, whatever the weather

Dressing should follow the "Layer Principle" this means that, layers are built up each of which has a different function. There is also the advantage that the number of layers can be adjusted according to how cold the temperature is and the activity of the wearer. A three layer system is most typical:

• Layer one: underwear / base layer (can be short and thin or long and "thermal")
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• Layer two: the insulating layer, tops & pants
• Layer three: outer shell layer