Why does the body create urine when it’s dehydrated? Shouldn’t it use the water to hydrate instead of creating a waste product?

Question

Why does the body create urine when it’s dehydrated? Shouldn’t it use the water to hydrate instead of creating a waste product?

In: 10

Answer 1

You’ve gotten good answers on the technical side. I’ll just add: we get a lot of questions here about “why doesn’t the body do this thing it would do if perfectly calibrated for this situation?” And the answer is often that the body is calibrated for the 99.99% scenarios, not the 0.01% scenarios. People get very thirsty reasonably often, but then they get to water and they’re fine. In those scenarios it would be quite bad if the body stopped removing waste for the hour before the person got to water.