Our brain cells shrink when they don't have enough water. Headaches are common when we don't have enough water. Negative thought patterns can develop when our brain cells don't have enough water. I can get my hand to go in and out like that without pain because around every joint, there's fluid. And that fluid is synovial fluid, and it is 99% water. In a state of dehydration, the body can take some water from there to maintain full blood volume in the major arteries and veins. And so, if I have pain in there, maybe it's called arthritis, but actually, maybe it's just a state of dehydration. Our eyeball moves around in water. So we need water at every single step.