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Looking at Dehydration (help)

canadarocks

Thinker
canadarocks
Joined
Oct 11, 2003
Messages
155
At work, I had noticed a poster that enumerated a number of claims about the effects of dehydration. Amongst the claims was that 75% of Americans were chronically dehydrated. That was enough to raise my suspicions so I started my internet searching. I found information (on Wikipedia) that discussed dehydration and a link for a web-site (I think Rehydrate.com) that indicated that the claim was made by this "Doctor" (forget the name). I also found through snopes that the claim by this "Doctor" is false. Does anyone have any additional information that I can check?

Thanks
 
Although the effects of being dehydrated may be overstated (http://www.craighospital.org/SCI/METS/h2o.asp), the percentage of people who are may not be. Most people simply do not take enough time out of their day to consume enough liquids. Most sites seem to recommend 64 ounces a day (http://www.cnn.com/HEALTH/library/NU/00283.html) but I'm sure this is for an average size sedentary person. How many people here actually drink that much liquid a day? I don't, and I'm downing water constantly at work all day, and I'm very active.

I think the best dehydration test is this: drink 12+ ounces of water and then wait an hour or two. Do you have to pee? If not, you're dehydrated.

Also, what information did you find on Wikipedia? I couldn't find any.
 
Quackwatch links to this truly excellent article, which provides evidence that most people don't need to drink eight glasses of water a day. This is not the same as evidence that people aren't dehydrated, of course, but in the process of debunking the myth, the author touches upon various related points. For example, that humans have a finely regulated sense of thirst, one that kicks in before any serious dehydration can take place, or that darker urine does not necessarily indicate dehydration. He also summarizes a variety of studies which looked at those with lower water intakes vs. those with higher and their susceptibility to a number of diseases, which, taken together, suggest that a high level of water drinking is only "better" under some very strictly defined circumstances. He also looks at some of the dangers of drinking too much water. (Incidentally, my personal experience with trying to drink more water on advice of a pediatriacian was that I got thoroughly nauseous after the third or fourth glass of water, and even doing the utmost to force myself, could not get past six. After two weeks, the experiment was discontinued, but the doctor kept insisting that really, it was good for me.)


P.S. - Strathmeyer, there's an extra parenthesis on the end of your first link, which inactivates it.
 
canadarocks said:
At work, I had noticed a poster that enumerated a number of claims about the effects of dehydration. Amongst the claims was that 75% of Americans were chronically dehydrated.
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In other words, either most people don't drink when thirsty, or our biological feedback mechanisms are so pathetic that we get dehydrated without getting thirsty. Neither scenario sounds very likely to me.
 
Ziggurat said:
In other words, either most people don't drink when thirsty, or our biological feedback mechanisms are so pathetic that we get dehydrated without getting thirsty. Neither scenario sounds very likely to me.
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I read some time ago (sorry, really can't remember where) that an increasing number of people mistake thirst for hunger.

[I seem to remember the lost article being related to drinking cola :confused: ]
 
I've been dehydrated, for real (4 days on a big wall in the baking sun - took a day and a half to pee again). I've been hydrated for real. You don't need 8 glasses of water a day to be hydrated. It's just not that hard to discern.
 
Thanks for all the great responses. I think I have enough to have the mis-information taken down. Also, I am tracking down the person who distributes these types of materials to ask that they do a little source checking before mis-informing others who are less skeptical of claims like these.
 
I read some time ago (sorry, really can't remember where) that an increasing number of people mistake thirst for hunger.

[I seem to remember the lost article being related to drinking cola ]
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I think part of the problem is that people often choose the wrong beverages when they're thirsty. My understanding is that coffee, tea, caffeinated sodas, and alcoholic beverages all act as diuretics, and make the problem worse. Perhaps, if this is not true, someone will enlighten me.

Meg
 
If I remember correctly the root of the confusion stems from a study that showed that humans need about 2 L of water a day to remain adequately hydrated. The important thing about that figure is that it includes water from food. Proponents of the "eight glasses a day" approach forget this.

In most cases you get a fair proportion of your daily water needs from the food you eat and thirst is the most reliable indicator that you need to drink.
 
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meg said:
I think part of the problem is that people often choose the wrong beverages when they're thirsty. My understanding is that coffee, tea, caffeinated sodas, and alcoholic beverages all act as diuretics, and make the problem worse. Perhaps, if this is not true, someone will enlighten me.

Meg
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Yup, absolute nonsense. From http://www.the-aps.org/press/journal/release8-13-02.htm

According to Valtin, there is strong scientific evidence that not all of the 8x8 needs to be taken in the form of plain water. Research conducted by Dr. Ann Grandjean and her colleagues has shown that caffeinated drinks – most coffee, tea and soft drinks – should count towards the daily fluid intake for the majority of people. The authors' conclusion that “advising people to disregard caffeinated beverages as part of the daily fluid intake is not substantiated by the results” of their study, was published in 2000, in the peer-reviewed journal, Journal of the American College of Nutrition.
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Your just not going to pee away all the fluid you drank, and you get most of the fluid you need from food anyway.
 
If any of my patients was observed voluntarily drinking an equivalent amount to that suggested for humans, I'd be investigating them for serious, pathological polydipsia, with serious concerns regarding kidney disease, thyroid disease, Cushing's disease and a load of other nasties.

Last time I looked, man was another mammal with a pretty similar homoeostatic system.

Rolfe.
 
It all depends on how much you need. When working in the Saudi desert, I regularly drank a half litre of water every hour during an 18 hour working day.

A rig medic advised me to go by urine output and condition. He said I should urinate as much and often as I did at home. There should be no stinging, no odour and no heavy colour. If this required me to drink a litre per hour, then that's what it took.

Insofar as I only collapsed once in ten years- and that after pulling a straight 71 hour shift under pretty extreme conditions- this regime seemed to work.
 
Soapy, sure. The problem is that this 8x8 nonsense is being followed by 100lb office workers.

There's also electrolyte dangers in what soapy is doing (if he doesn't supplement the water). Marathoners have collapsed, even died, because they drank too much water while sweating away their electrolytes.

I don't know the accuracy of this, but in mountaineering (where you get very dehydrated from the combination of high exertion and dry air from the high altitude) the general advise is that your body absolutely cannot process more than 8 oz every 20 minutes. Anything more is turned to pee. So don't climb for an hour and then gulp down a water bottle. Most of it will be wasted. I use that as a guideline for drinking in extreme situations. Could be wrong, though.
 
NFL players will drink several gallons during a game, and still end up losing 10 pounds. I guess it depends on need. Personally, I figure that if my urine is clear once a day, my filters are getting flushed out adequitly. Coffee, beer, or whatever, it is still flushing out my kidneys.
 
I said "water" . Actually a mix of water, apple juice, the odd 7-up, tea, coffee, milk and at least one glass of effervescent vit C or mineral salts a day.
One thing I never used was salt tabs.
At high altitude, you want hot drinks anyway. In low altitude climbing, moving fast, I always drank a lot, because I sweated so much. I've been above 18,000ft a few times and found I did not drink much at all, because I moved much slower.
Let's face it, individual variance will be huge here. The important thing is to pay attention to what your body tells you. If you are OK, you know it.
 
Electorlyte imbalance is pretty rare, and you generally don't need salt tabs (even in desert). The problem mainly arises if you start skipping meals (or skimping meals), which can be problematic in the desert. THe heat tends to make one lose thier appitite (sp?).

We had one case of brain swelling due to electrolyte imbalance during our trip to Iraq and back, and that was a tanker who had missed breakfast and lunch, and spent all day inside an Abrahms. And that was at Ft. Hood, during our train-up. We had over a dozen cases of dehydration severe enough to require medical intervention, and one death from dehydration.
 
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