Operations in Iraq have been noted for one thing in particular; heat. But "heat casualties" are nothing unique for the U.S. Army. Most of the army's bases are in the southern United States, and it's main combat training, Ft Irwin, is in a western desert. American troops have plenty exposure to heat, and in 2002, suffered 1,816 serious (requiring medical care) heat casualties. That comes down to 3.8 cases per thousand troops per year. Interestingly, the rate for the combat arms was a little lower, at 3.7, than the average. This probably has to do with the combat troops being in better shape physically, and more sensitive to the possibility of heat injury. Nevertheless, the 2002 rate is the highest it's been in many years. In 2001 it was 3.4, in 2000 2.5, 1999 2.1 and 1998 2.2. This is attributable to increased training, which puts a lot of non-combat troops out in the heat. The most vulnerable to heat casualties are women under age 20, although men and women under 20 together had a rate of 8 in 2002. The high heat casualty rate for young troops is largely because that's when these troops are going through their initial training and are most out of shape and inexperienced.