A small dip in fluids can make the whole body feel off. Legs feel heavier. Getting up from a chair takes more effort. A short walk feels longer than it should. Balance can feel less steady, even when nothing else has changed. Hydration is one of those simple habits that quietly supports almost everything the body does. It helps muscles contract, nerves send signals, blood move through the body, joints stay comfortable, and the brain stay alert. For older adults, that matters