If our core temperature goes above 104º, the body begins to overheat to the point where its proteins denature. When this happens, "membranes of the tissues lose their integrity, and things leak out," Spriet says. The intestines can discharge bacteria into the bloodstream, and the body goes into shock. But by then we would probably be unconscious, maybe even in a coma. The whole point of sweat, of course, is to prevent this from happening by keeping us cool. But even while our innards ooze, we may still perspire. As Armstrong points out, it's impossible to sweat out all the water in our bodies: "People don't shrivel up until they are dead."