Why do you sweat when exerting energy?

Ok. . .let me correct this terrible terrible wrong that was originally written here. The body is like a machine much like a car or computer even. Machines when exerting energy also create great heat; due to mechanism within us called "homeostasis", which seeks to create balance like keeping our body temperature regulated and stable. Basically we take oxygen and water not only for the typical reason but to also to cool down our body, as water is absorbed through our stomach lining and oxygen is absorbed through our lung tissue each is taken directly into our blood stream to our respective organs and muscle tissue that need it most. Which is why when we work harder our blood moves faster to get oxygen and water to our parts faster much like a radiator and oil pump in a car. Blood when getting to the muscles that need it most pick up waste from our muscles while simultaneously dropping off fresh water and oxygen for it to use. . .of course blood can't handle the whole load so we also in addition to blood simply push the residual waste to the top epidermal layer of the skin (sweat). . . .The rest of course is taken to the kidneys, filtered out and dropped in our bladder awaiting expulsion.