How much water do we need to drink to survive?
Surprisingly little. And the “8 full glasses a day” thing is not the correct answer. It is too general and not based on solid research.
I read this first in a book called “Evolutionary Medicine” by Stephen C. Stearns and Ruslan Medzhitov. I got quite a few surprises. Like that the edema (swelling) you get after injuring a joint like the ankle, is actually a form of splinting. It limits movement around the joint, preventing further damage. Recall the “RICE” mnemonic: Rest, ice, compression, and elevation? Turns out you only require ”R.”
Now water. It's been a few years since I read the book so my memory may betray me a little, but there is no one magic formula, and it's less than you think. Humans in hot and arid regions obviously need more than say those in Scandinavia. Those of us who are physically active need more than the sedentary. The answer also depends on body height and weight and Body Mass Index. Bigger people need more fluids.
The 8FGpD approach says to never let your mouth get dry, and don't let your urine turn dark yellow or orange. EM says that's nonsense. A dry mouth is merely a measure of comfort, not hydration. For example, I have dry mouth because of certain meds I take and all I need do is to swish-and-swallow a quarter cup of water to feel comfortable again. And my pee rarely turns shades.
So how do you calculate how much YOU need? No clue. It's in the book but since it's cost prohibitive right now, I guess I'll find the correct Answer when I can afford it.
