That's right, the first sign of thirst means the body is 2% dehydrated. 15% water loss is right about where people die from dehydration. If your body is about 60% water, and you weigh 200lbs, 2 percent is about 38oz (or 2.4 lbs). Like these guys have already mentioned, drinking more than your body needs usually ends up being excreted by the body. You'd have to try really hard in order to over-hydrate yourself.
Oh, and the brain is 85% water, so you can see how dehydration can cause dizziness, dimmed vision, drowsiness, etc.
Last edited by davidm724; 09-22-2007 at 04:23 AM.