During a day of strenuous activity, a person can lose ten liters of water. As the body burns energy during physical exertion, it creates heat. It then produces sweat, which provides a cooling effect as it evaporates. A sweaty person in wet clothes can lose heat rapidly if inactive in frigid temperatures. Each member of Will Steger's team will wear five layers of clothing that provide insulation .
Explorers can peel off or put on layers as weather conditions and activity levels change.
The first layer consists of long underwear made of a lightweight, synthetic material that allows perspiration to move away from the skin to the second layer, a synthetic fleece shirt and pants. As it wicks moisture away, the quick-drying fleece helps the underwear layer provide warmth. Next, a jacket covers the first two layers, offering insulation. The fourth layer, a lightweight second jacket made of very fine, tightly woven microfibers , slows the rate of moisture loss . Team members also wear mukluks, flexible boots designed by the Inuit people and made of animal hides and canvas.