In today’s Army, Soldiers may deploy and fight anywhere in the world. They may go into the tropical heat of Central America, the deserts of the Middle East, and the frozen tundra of Alaska. Each environment presents unique situations concerning a Soldiers’ performance. Furthermore, physical exertion in extreme environments can be life threatening. While recognizing such problems are important, preventing them is even more important; and furthermore, requires an understanding of the environmental factors that affect performance and how the body responds to those factors.