It all begins with the hypothalamus, the gland responsible for regulating our body temperature and triggering the processes that balance the fluids in our bodies. When the hypothalamus detects too little water in our blood, it signals the release of an anti-diuretic hormone that causes the kidneys to remove less water from the blood. The result? We pee less, and when we do, our urine is more concentrated and darker in color. At this point the brain also tells us we’re thirsty, and once we sip on some water or consume something hydrating our water levels return to normal . Similarly, when our body temperature rises either from fever, working out, or being in a warm environment, our bodies try to lower our temperature by sweating: When sweat evaporates from our skin, it takes some heat with it, helping to cool us off.
