Question on metabolism, hydration, and peeing

Factual Questions
1

After working under the hot sun, I get thirsty. I guzzle a ton of water. If this water is “absorbed” (this is where I lack basic skills to even describe), do I or don’t I have to pee more pee? Isn’t that water used up, so to speak, and things have reached an equilibrium, and the metabolism reverts to status quo ante, with pee volumes as normal?

You’d think I would have checked this empirically, but results are scattered.

Extra credit: If anyone can add the words “This is probably basically true/not true for dogs” (or words to that effect), it would settle endless arguments with my wife on when to take my beast out.

Thanks.

2

Are you asking if a dehydrated individual (even if not extremely so) can drink more water before experiencing increased urination compared to the same individual who isn’t dehydrated?

3

I believe I’m asking: when someone is dehydrated, and then hydrates himself to “normal” levels (I don’t know that that means, scientifically)–that is, he feels back to normal–does the extra water he has taken in been absorbed in some way, and so he does not need to pee more volume than before, or
does the extra water in his system mean that he has to pee more?

4

If you’re dehydrated, your body will absorb water until it’s back to normal. Excess water will pass out of the body. Don’t over think it. Pee often; pee clear. The same is true for your dog.

5

You get thirsty working in the hot sun because you loose a lot of water as sweat. You need to drink more in order to replace the lost water. If you drink more than is needed to keep the water balance of your body, the excess is excreted through the kidneys.

6

My own personal experience: I once hiked Horseshoe Canyon in Utah, in extremely high temperatures and more exertion than I was accustomed to. Throughout the day I drank three gallons of half Gatorade/half water, and did not pee once until I was back in my cabin late at night.

7

I suspect that your logic is sound. The problem begins when theory turns into practice. If you would indeed drink only enough to restore the equilibrium, your urine output should remain normal. But you’re probably so thirsty that you’re drinking more than you actually need, and that’s where the surplus comes from.

When you drink, it takes time for the water to get from your throat to the parts of the body that need it. By the time your body says, “Okay already!” you’ve probably overdone it, and you have a belly full of water just sloshing around ready to come out. This may be why it is recommended to have frequent small drinks.

8

John Campbell, the legendary science fiction editor from Astounding (Analog) magazine, discussed thistopic in one of his letters with an author (read his 2 volumes of collected letters). Someone mentioned the exact same phenomemon, working on a road crew and drinking gallons of water which never makes it to their bladder.

Humans evolved on the plains of Africa to chase down game. Once we came out of the trees, our two-legged stance made us far more capable of outrunning anything else in a marathon - yes, a horse or gazelle can outrun a human in a foot race, but over many hours, humans can run down any large animal that cannot stop and recuperate for a long time after a sprint.

(See a horse after a race; after a strenuous run, it just stands there soaking wet with sweat. An overworked horse is more likely to keel over from exhaustion. Plus, all that burned energy results in byproducts that need to be excreted - hence, pee like a racehorse.)

To accomodate this, we lost insulating body hair and developed a very efficient sweating mechanism to regulate body temperature (downward). You may be drinking a gallon or 3 of water, but other than rehydrating to normal levels, all the rest either comes out as urine or sweat. The thing is, in very hot but not excessively humid weather, that sweat evaporates as soon as it comes out - meaning you don’t realize just how much is coming out. Again, what doesn’t come out your bladder comes out your sweat glands - it just evaporates right away.

Of course the warning is that you may be losing a large amount of electrolytes. If it weren’t for the fact that North Americans oversalt their food so badly, you would be wanting to drink gatoraid or take salt pills.

OTOH, I also recall reading that dogs do not sweat. Neither do pigs. Dogs regulate body temperature through breathing and by letting their tongue hang out in the breeze (Hence the dog in the car drooling out the window). The fluffier dogs like huskies or german shepards are probably not too efficient in hotter times, but that’s not the climate their body has evolved for - when you’re chasing something through the snow at 32F the tongue is probably sufficient. Pigs, BTW, regulate body temperature by rolling in the mud, or whatever is soft and wet if they are confined in a pen.

So you, drink whatever you need in hot weather. Ditto the dog, but he’s more likely to pee than you if he over-consumes. You can sweat a lot more than he can drool.

9

To break it down: Your (presumably healthy) body knows how much it needs; what it does not need will flow from your wee-wee.
mmm