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dolphinboy
09-13-2005, 11:08 AM
I was sitting with some coworkers waiting for a meeting to start when someone mentioned that they had quit drinking coffee a few weeks ago and that they were feeling "dehydrated" all the time. (They had been a heavy coffee drinker so they figured that by not drinking coffee they were consuming a lot less liquid than they used to).

Since I had always thought that coffee was a diuretic, which would presumably dehyrate someone, I was a little surprised to hear this but before I could chime in someone else suggested that this person take a shower to "rehydrate" themself. Before I could ask how they could do this someone else mentioned that taking a shower is equivalent to drinking 6-8 glasses of water.

I had taken a number of physiology classes in college and I was pretty sure this was compeltely bogus but somone else chimed in that they had read the same thing somewhere. I never thought of our skin as some kind of sponge and that water would pass through into our cells at anything like that kind of rate.

So are these people crazy or do you really absorb large amounts of water when you take a shower, take a bath, go swimming etc? I just can't believe that it really happens...

CookingWithGas
09-13-2005, 11:26 AM
They are nuts. Not an expert at this but I do know that although your skin's outer layer's can absorb water (that's why your fingers get pruny) you can't absorb water into your bloodstream that way. Taking a shower or bath, or swimming are in no way equivalent to drinking water.

BTW caffeine is a diuretic, although I don't know if the diuretic effect is large enough to cancel out the fluid you drink when you have a cup of coffee.

Qadgop the Mercotan
09-13-2005, 11:37 AM
Most regular caffiene (and alcohol) drinkers get relatively immune to the diuretic effects of their chosen substance.

WhyNot
09-13-2005, 11:38 AM
I have no idea, but just want to point out that your username/post combo made me smile. :p

Qadgop the Mercotan
09-13-2005, 11:44 AM
Oh, and just to re-iterate CookingwithGas's point: One does not absorb any significant amounts of water into one's circulatory system via the skin.

CynicalGabe
09-13-2005, 11:57 AM
You work with a lot of people that need to join this board and read Snopes. ;)

Cervaise
09-13-2005, 03:37 PM
A few weeks ago, out of idle curiosity, I weighed myself before and after a shower. According to the scale, which is a digital model that rounds to the nearest 0.5 lb, the shower added half a pound. "Really?" I thought, and tried it again the following day. No difference. Ditto the day after. I concluded that the shower does add a small amount of weight via absorption, but less than half a pound, and that my initial measurement was a result of rounding: say, X.2 before, rounded to X.0; X.4 after, rounded to X.5.

So there you go, actual data. :)

Given that 6-8 glasses of the stuff would weigh at least a couple of pounds (1 liter = 1 kilogram), I think the co-worker's statements don't hold, well, water.

scr4
09-13-2005, 03:44 PM
I concluded that the shower does add a small amount of weight via absorption...
Or it could be adhesion. Did you dry yourself thoroughly, including your hair, before making the "after" measurement?

Erinaceus europaeus
09-13-2005, 03:47 PM
A few weeks ago, out of idle curiosity, I weighed myself before and after a shower. According to the scale, which is a digital model that rounds to the nearest 0.5 lb, the shower added half a pound.

Half a pound seems a lot. Could it be most of that weight is in your wet/damp hair? - It's a shame I have no scale.

TimeWinder
09-13-2005, 03:49 PM
...I concluded that the shower does add a small amount of weight via absorption, but less than half a pound, and that my initial measurement was a result of rounding: say, X.2 before, rounded to X.0; X.4 after, rounded to X.5.

So there you go, actual data. :)



Unfortunately, here's some more data: I just weighed myself on a (0.1 lb resolution) digital scale five times, about twenty seconds apart. I got a range of 1.9 lbs, and I've gotten larger ranges in the past on consecutive weighings - depending mainly (I think) on where exactly I place my feet on the scale.

But even if we assume that Cervaise is gaining weight in the shower (and not, say, showering with snack foods), I think that I'd be more inclined to guess that hair is absorbing (weighable quantities of) water than skin.

TimeWinder
09-13-2005, 03:51 PM
Heh - three brilliant minds, all thinking alike in suspecting hair, within three minutes!

Sal Ammoniac
09-13-2005, 03:55 PM
Not wholly off topic, but it always seems to me that swimming (whether in a pool or the ocean) makes you need to pee more. Anyone else notice this? It's tempting to think you're absorbing water through your skin, but I suspect in reality that being in the water inhibits sweating, meaning that wastes need to come out through your urine, rather than your skin. I could be wildly off the mark, but for the moment, I'm clinging to my illusions.

Skammer
09-13-2005, 03:59 PM
What about inhaling water vapor during a hot shower? I mean, the weight would probably be negligible, but that would at least be additional moisture entering your bloodstream. Or not?

Excalibre
09-13-2005, 04:03 PM
I was sitting with some coworkers waiting for a meeting to start when someone mentioned that they had quit drinking coffee a few weeks ago and that they were feeling "dehydrated" all the time. (They had been a heavy coffee drinker so they figured that by not drinking coffee they were consuming a lot less liquid than they used to).

Since I had always thought that coffee was a diuretic, which would presumably dehyrate someone, I was a little surprised to hear this but before I could chime in someone else suggested that this person take a shower to "rehydrate" themself. Before I could ask how they could do this someone else mentioned that taking a shower is equivalent to drinking 6-8 glasses of water.
Wait, were your co-workers implying that the decaffeinated co-worker hadn't had a shower in the several weeks since he'd given up coffee? Doesn't he presumably take showers often enough that he'd already have solved the problem?

dolphinboy
09-13-2005, 04:11 PM
The coworker who complained about being dehydrated wasn't one of the ones that claimed taking a shower would hydrate you. In fact they were just as perplexed by the whole thing as I was :rolleyes: .

Hampshire
09-13-2005, 04:20 PM
If it was true that a shower would re-hydrate you wouldn't it make sense that during the winter when the air is dry and your skin is dry that a shower would re-hydrate your skin. On the contrary a shower actually makes your skin dryer.

Ask an olympic swimmer if they need to drink anything during practice to stay hydrated? Or does just being in the pool keep them hydrated just fine?
I'd vote for they have to drink something.

Napier
09-13-2005, 04:22 PM
I'd think any water you absorbed into skin to make it pruny, and any water vapor that condensed into your lungs, would have to increase your hydration via the bloodstream. All these cells are drifting around equilibria and sharing fluids with the bloodstream. But I bet it isn't much, maybe a few ounces for a long exposure.

A shower would also affect your sweating and the water loss associated with humidifying breath. Preventing a few ounces of loss must be somehow equivalent to gaining a few ounces.

I read somewhere that you can get as much as 10% of your oxygen by absorption through the skin, which makes me wonder whether a special dermabrasion and cold oxygenated water soak (or some such) could be supplemental therapy for someone in respiratory distress. And of course there are many drugs and poisons you can absorb through the skin. Sounds reasonable (though maybe small) to me.

scm1001
09-13-2005, 04:32 PM
Not wholly off topic, but it always seems to me that swimming (whether in a pool or the ocean) makes you need to pee more. Anyone else notice this? It's tempting to think you're absorbing water through your skin, but I suspect in reality that being in the water inhibits sweating, meaning that wastes need to come out through your urine, rather than your skin. I could be wildly off the mark, but for the moment, I'm clinging to my illusions.

I suspect that the real reason is that the cold water makes you pee more, because the body reroutes more blood to the internal organs, including the kidneys to save heat.

Qadgop the Mercotan
09-13-2005, 06:28 PM
I read somewhere that you can get as much as 10% of your oxygen by absorption through the skin
Sorry, untrue. We breath thru our lungs. NOT our skin.

QtM, MD

Mcmouzer
06-27-2013, 01:13 PM
I've been working out for a year now. Went from 235 pounds to my current weight of 188 (depending on how hydrated I am).

This morning, I weighed myself after my "morning constitutional" and before my morning 5 mile run. I weighed 186.5.
Then I ran 5 miles.
Weighed myself again and I weighed 185.5- a loss of one pound.
I then showered. After showering, I weighed myself again...
188.5 pounds!

So either my digital scale is whacked, or...

One gallon of water = approx. 8 pounds.
There are eight pints to a gallon, so a pint of water weighs 1 pound.

It is wholly conceivable that I sweated a pint during my 5 mile run. That would explain the weight loss of one pound.

Important to note:
After sleeping through the night, I assume my body dehydrates, as I'm simply not taking in any water while sleeping. SO in the morning, I'm dehydrated.
I don't drink any water before my run, because I can't run far with anything in my stomach. Also- I've dropped whatever weight in urine and feces before my run, dehydrating myself further. Not to be gross, or risking TMI, I urinate at least a pint, and without TOO much investigation, I'd estimate that I drop at least a quarter pound in feces.

So I'm dehydrated with clear bowels at the start of my run.

The three pound of gain after showering MUST be from water absorption during my shower. In this morning's case, I took a cool, prolonged shower (just to address the water vapor issue).

My scale is a reasonably accurate standard bathroom digital scale. No matter where I stand on it, it rests the same weight.

So my dehydrated state caused my skin to be dehydrated, and I must have absorbed three pints of water during my shower!

Three pints sounds like a lot, but I don't think my scale lies...

My 2 cents.

Machine Elf
06-27-2013, 02:48 PM
What about inhaling water vapor during a hot shower? I mean, the weight would probably be negligible, but that would at least be additional moisture entering your bloodstream. Or not?

Your lungs need something close to 100% relative humidity in the air in order to work properly; your nostrils, trachea, bronchi and bronchioles generally take care of this. This is why your exhaled air is so moist.

If you're inhaling very humid air, this reduces the moisture requirement from your lungs; that is, it will reduce the rate at which your body loses moisture, but it will not add moisture to your body.

If you live in an extremely dry climate (e.g. Boulder, Colorado in the wintertime), you can lose a lot of moisture just through respiration.

As for the OP's tale:
someone else mentioned that taking a shower is equivalent to drinking 6-8 glasses of water.

This is a pretty easy one to check:

1. Beginning in a healthy state of hydration, take a 20-minute shower.
2. keep a written record of your total urine output volume over the subsequent two hours.
3. the next day, beginning in a healthy state of hydration, drink 6-8 glasses of water over a 20-minute period.
4. keep a written record of your total urine output volume over the susequent two hours.
5. Compare the two written records.

My prediction is a huge discrepancy between the two written records.

DataX
06-27-2013, 02:55 PM
I've been working out for a year now. Went from 235 pounds to my current weight of 188 (depending on how hydrated I am).

This morning, I weighed myself after my "morning constitutional" and before my morning 5 mile run. I weighed 186.5.
Then I ran 5 miles.
Weighed myself again and I weighed 185.5- a loss of one pound.
I then showered. After showering, I weighed myself again...
188.5 pounds!

So either my digital scale is whacked, or...

One gallon of water = approx. 8 pounds.
There are eight pints to a gallon, so a pint of water weighs 1 pound.

It is wholly conceivable that I sweated a pint during my 5 mile run. That would explain the weight loss of one pound.

Important to note:
After sleeping through the night, I assume my body dehydrates, as I'm simply not taking in any water while sleeping. SO in the morning, I'm dehydrated.
I don't drink any water before my run, because I can't run far with anything in my stomach. Also- I've dropped whatever weight in urine and feces before my run, dehydrating myself further. Not to be gross, or risking TMI, I urinate at least a pint, and without TOO much investigation, I'd estimate that I drop at least a quarter pound in feces.

So I'm dehydrated with clear bowels at the start of my run.

The three pound of gain after showering MUST be from water absorption during my shower. In this morning's case, I took a cool, prolonged shower (just to address the water vapor issue).

My scale is a reasonably accurate standard bathroom digital scale. No matter where I stand on it, it rests the same weight.

So my dehydrated state caused my skin to be dehydrated, and I must have absorbed three pints of water during my shower!

Three pints sounds like a lot, but I don't think my scale lies...

My 2 cents.

I highly doubt any "standard" bathroom scale is that accurate. I've heard of ones that will repeat certain measurements taken with a certain period of time though.

And of course what you are saying is unknown to science...

johnpost
06-27-2013, 03:44 PM
zombie or no

you need to test the scales with dry weight. take 50 lbs of dry weight (exercise weights would work).

adjust the scale to zero when its reading is stable. put the 50 lbs on the scale. record the weight. repeat 10 times. compare.

you need to allow plus or minus for the variation you see (or is stated by the manufacturer) whichever is greater.

you can't compare with your body from one day to the next because of water on the hair and food, shit, water inside will vary.

aruvqan
06-27-2013, 04:36 PM
Heh - three brilliant minds, all thinking alike in suspecting hair, within three minutes!
Makes me wish we had a seriously accurate scale - mrAru has alopecia and absolutely no hair anywhere to hold water. [His normal comment is that he really misses his nose hairs:p]

friedo
06-27-2013, 04:40 PM
So either my digital scale is whacked, or...


Bathroom scales are not renowned for their accuracy. Especially if you change their temperature.

Der Trihs
06-27-2013, 04:54 PM
zombie or no

you need to test the scales with dry weight. After 8 years, the zombie's probably pretty dried out. That might make it really absorbent, come to think of it. You'd think that a soggy zombie would weigh a lot more than a dried out zombie.

Roderick Femm
06-27-2013, 05:02 PM
Since it's a zombie thread anyway, I will pop in here with a rhyme that my mother taught me a long time ago, about how much water weighs:

A pint's a pound
the world around


That is all. Cheers,


Roddy

Whitney Harper
06-27-2013, 05:58 PM
There are so many water purifiers for showerheads on the market, and that would make one think that the body does indeed absorb water.

Great Antibob
06-27-2013, 06:17 PM
A pint's a pound
the world around


True or close enough for US pints.

Imperial pints are 1.25 pounds (Imperial gallons are exactly 10 pounds of water), so over there, it's "A pint of water is a pound and a quarter".

friedo
06-27-2013, 06:19 PM
There are so many water purifiers for showerheads on the market, and that would make one think that the body does indeed absorb water.

Would it? Or would it make one think that perhaps many people are gullible enough to buy a water purifier for their shower head?

Great Antibob
06-27-2013, 06:27 PM
Do you mean water softeners? That's actually pretty common but not because of absorption of water.

I guess if you use well water for your shower, you might want to filter out lead or sulfur or other stuff (maybe chlorine, if you're so inclined), so it's possible to have a shower filter. But again, that's nothing to do with absorption of water and with what else is in the water.

Lasciel
06-27-2013, 06:31 PM
Would it? Or would it make one think that perhaps many people are gullible enough to buy a water purifier for their shower head?

This is in no means intended to prevent knocking of gullible people who are buying water purifiers for the intent of absorbing water through their skins, but I will make two (three) notes:

1) some people (myself included) brush their teeth and drink from the shower.

2) most soaps and shampoos are designed to work with a certain level of water "hardness" or "softness" and the purifiers help with that, making the sudsing action work better (please note the cleansing action is not actually much changed by the sudsing, but it makes most people happy to have big foamy suds, so there it is.)

(I couldn't resist (Hi, Opal!) - 3) placebo affect - they think their water is PURE for their shower, they feel healthier because of it, they ARE healthier.)

moriah
06-27-2013, 09:07 PM
Also... recent research shows that pruny skin is not water absorption. After all, does all your skin everywhere become pruny?

The pruning happens internally, not externally. It's a bodily response to being in water. The leading theory is that it increases grip on slippery surfaces.

WhyNot
06-27-2013, 09:18 PM
Was just going to add that, moriah. I didn't know that back when this thread made it's first rounds. The latest thinking is that raisin fingers are because of nerve response, nothing to do with dehydration or overhydration.

Also, you have to pee after swimming because, well, you have to pee every couple of hours anyhow. But also because the weight of the water encourages fluid to move into the lymph vessels and ultimately to the bladder and out as urine. Swimming pools, and even bathtubs, are a common recommendation for reducing edema in the feet and ankles. It's like temporary compression stockings, without the fashion crime.

Senegoid
06-27-2013, 09:23 PM
Sorry, untrue. We breath thru our lungs. NOT our skin.

QtM, MD

Maybe you are making too many assumptions about the posters who claim to breathe and hydrate through their skin.

On the Internet, nobody knows if you're a frog.