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Here's a post I've come up with about myths concerning water. It concerns a lot of widely held long time beliefs that I believe are false about water.

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I wrote it in response to one of perhaps thousands of articles purporting the alledged need for copious amounts of water and the almost magical properties water supposedly has--

There's hundred's of articles out there touting the "magical" properties of water, but none that back up their statements with any referenced scientific explanations. That's because it's become such "common knowledge" that to question it seems to go against everything we deem to be holy and it almost seems un-American to go against it. Most of this is pushed by bottled water companys that have found a gold mine in selling us water that's no better than we can get from our own tap.

There's absolutely no scientific evidence to support the well entrenched belief that we need this much water (8 glasses of 8 ounces a day) or that it does the things that a lot of articles purport.

For starters the idea that water "flushes out" anything is erroneous. It's not like the faster the water goes through you the more likely it is to pick up toxins like flushing dirt off the hood of a car. The body maintains a steady water level via the sodium/potassium electrolyte system. Excess water is simply excreted. Toxins, viruses or whatever do not adhere to water molecules anyway so they are uneffected by water. That's why you have an immune system. Water simply transports t-cells, macrophages et.al. and other components of the immune system to the toxins to destroy and/or eliminate them.

If you are deficient (dehydrated) than you need enough to replenish back to normal levels. Excesses don't help anything or speed up any processes. Excess water is asimilated through the duodenum and the rest of the colon goes into the blood and then the kidney's excrete all excess. The extra water never even makes it into the cells to do any good.

There's a lot of myth's concerning water consumption. The two biggest are:

1. That only water that is straight water is any good. Not true. Water is water as far as the body is concerned whether it's from tap, coffee or from a bannana.

2. Another myth is that everyone needs 8 glasses a day.

The origination of this recommendation of 8 glasses of water is hard to find. One idea says it comes from a mis-reading of an outdated 1945 National Research Council study that's explain a little later. Another idea is that it came from a World War 2 study trying to determine the amount of water a typical soldier had to have available for himself.

The following is a little long and I apologize for it. However, it should be enough to expunge some of the these commonly held myths:

Recommended Water Intake A Myth, Heinz Valtin, MD, DMS, et. al.

It has become accepted wisdom: "Drink at least eight glasses of water a day!" Not necessarily, says a DMS physician Heinz Valtin, MD. The universal advice that has made guzzling water a national pastime is more urban myth than medical dogma and appears to lack scientific proof, he found. In an invited review published online by the American Journal of Physiology August 8, Valtin, professor emeritus of physiology at Dartmouth Medical School, reports no supporting evidence to back this popular counsel, commonly known as "8 x 8" (for eight, eight-ounce glasses). The review will also appear in a later issue of the journal.

Valtin, a kidney specialist and author of two widely used textbooks on the kidney and water balance, sought to find the origin of this dictum and to examine the scientific evidence, if any, that might support it. He observes that we see the exhortation everywhere: from health writers, nutritionists, even physicians. Valtin doubts its validity. Indeed, he finds it, "difficult to believe that evolution left us with a chronic water deficit that needs to be compensated by forcing a high fluid intake."

The 8 x 8 rule is slavishly followed. Everywhere, people carry bottles of water, constantly sipping from them; it is acceptable to drink water anywhere, anytime. A pamphlet distributed at one southern California university even counsels its students to "carry a water bottle with you. Drink often while sitting in class..."

How did the obsession start? Is there any scientific evidence that supports the recommendation? Does the habit promote good health? Might it be harmful?
Valtin thinks the notion may have started when the Food and Nutrition Board of the National Research Council in 1945 recommended approximately "1 milliliter of water for each calorie of food," which would amount to roughly two to two-and-a-half quarts per day (64 to 80 ounces). Although in its next sentence, the Board stated "most of this quantity is contained in prepared foods," that last sentence may have been missed, so that the recommendation was erroneously interpreted as how much water one should drink each day.

He found no scientific studies in support of 8 x 8. Rather, surveys of fluid intake on healthy adults of both genders, published as peer-reviewed documents, strongly suggest that such large amounts are not needed. His conclusion is supported by published studies showing that caffeinated drinks, such as most coffee, tea and soft drinks, may indeed be counted toward the daily total. He also points to the quantity of published experiments that attest to the capability of the human body for maintaining proper water balance.

A study on dieting does not show a significant improvement in weight loss resulting from more drinking. Likewise, constipation, sometimes thought to be alleviated by drinking, is not discernably impacted by an extra intake of 4 to 8 glasses of water.(1)

Valtin emphasizes that his conclusion is limited to healthy adults. But barring that exception, he concludes that we are currently drinking enough and possibly even more than enough.

Despite the dearth of compelling evidence, then, What's the harm? "The fact is that, potentially, there is harm even in water," explains Valtin. Even modest increases in fluid intake can result in "water intoxication" if one's kidneys are unable to excrete enough water (urine). Such instances are not unheard of, and they have led to mental confusion and even death in athletes.

And he lists other disadvantages of a high water intake: 1. possible exposure to pollutants, especially if sustained over many years;2. frequent urination, which can be both inconvenient and embarrassing; 3 expense, for those who satisfy the 8 x 8 requirements with bottled water; and 4 feelings of guilt for not achieving 8 x 8.

Other hazards associated with enhanced water consumption. Hyponatremia is a situation where too much water consumption has resulted in the dilution of sodium and other essential chemicals in the cells of the human body. In the extreme, this can lead to death. Another concern is that more drinking of water leads to an enhanced consumption of pollutants in water - both bottled water and tap water contain bacterial and chemical pollutants that become absorbed in the body. Last but not least, bottled water is unnecessarily expensive. (1)

Another example of over-drinking: in 2002, several runners in the Boston marathon suffered from hyponatremia, and one of them died as a result. Several other marathon deaths have been reported - not as you might expect, from dehydration! Rather, they are a result of hyponatremia resulting from over-hydration. The elite runners (those who finish under 4 hours) are experienced enough to drink very little during the race, and do not suffer from this problem. However, the less experienced athletes (typically those who run 4 hours and more) think they need to drink profusely, and consequently suffer from this life-threatening problem. (2-3)

***Other claims discredited by scientific evidence that Valtin discusses include:

1. Thirst Is Too Late. It is often stated that by the time people are thirsty, they are already dehydrated. On the contrary, thirst begins when the concentration of blood (an accurate indicator of our state of hydration) has risen by less than two percent, whereas most experts would define dehydration as beginning when that concentration has risen by at least five percent.

2. Dark Urine Means Dehydration. At normal urinary volume and color, the concentration of the blood is within the normal range and nowhere near the values that are seen in meaningful dehydration. Therefore, the warning that dark urine reflects dehydration is alarmist and false in most instances.

Is there scientific documentation that we do not need to drink "8 x 8"? There is highly suggestive evidence, says Valtin. First is the voluminous scientific literature on the efficacy of the osmoregulatory system that maintains water balance through the antidiuretic hormone and thirst. Second, published surveys document that the mean daily fluid intake of thousands of presumably healthy humans is less than the roughly two quarts prescribed by 8 x 8. Valtin argues that, in view of this evidence, the burden of proof that everyone needs 8 x 8 should fall on those who persist in advocating the high fluid intake without, apparently, citing any scientific support.

Finally, strong evidence now indicates that not all of the prescribed fluid need be in the form of water. Careful peer-reviewed experiments have shown that caffeinated drinks should indeed count toward the daily fluid intake in the vast majority of persons. To a lesser extent, the same probably can be said for dilute alcoholic beverages, such as beer, if taken in moderation.

"Thus, I have found no scientific proof that every person must drink at least eight glasses of water a day'," says Valtin. While there is some evidence that the risk of certain diseases can be lowered by high water intake, the quantities needed for this beneficial effect is much less than 8 x 8, and the recommendation can be limited to those particularly susceptible to the diseases in question.

So everyone can quit feeling guilty that they're depriving themselves of optimum health, save your money and just drink when you're thirsty. Trust your body, it's smarter than you think.

Iron

References--

(1) "Drink at least eight glasses of water a day". Really? Is there scientific evidence for "8X8"? Am. J. Physiol. Regul. Integr. Comp. Physiol. v 283, p 993 (2002)

(2) "Drink plenty of fluids": a systematic review of evidence for this recommendation in acute respitory infections. British Medical Journal v 328, p 499 (2004).

(3) Hyponatremia among Runners in the Boston Marathon, New England Journal of Medicine v 352, p 1550 (2005)

__________________
There are in fact, two things: science, and opinion; the former begets knowledge, the latter ignorance. -Hippocrates of Cos
"New opinions are always suspected, and usually opposed, without any other reason but because they are not already common." —John Locke
"And you shall know the truth, and the truth shall make you free.” - Jesus Christ

"Perago Validus"

I agree.

I posted this before: http://intl-ajpregu.physiology.org/c...ull/283/5/R993

I'm not sure if that's one of the same references you posted, it may be.

I also posted something on the kidneys which actually speaks to this a little and I think might add to it. I'll post it here if I can dig it up.

I personally like to get well hydrated around my workouts just to be sure, because sometimes I tend to be thirsty and ignore it. I am not always good about hydrating myself. I try to drink lots of water but I don't think for a second that there is any advantage whatsoever in me trying to down gallons of the stuff...or any other water containing beverage.

Edit* The link I posted is for the one you posted by Heinz. I'll leave it up in case someone wants to see it for themselves but it's the same thing.

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If you act sanctimonious I will just list out your logical fallacies until you get pissed off and spew blasphemous remarks.

Here is an article that discusses the review I've just posted:

By: Mauro Di Pasquale

Almost everyone agrees that water is good for you and that the biggest problem with water intake is that you don't drink enough. We have all had it drummed into us that we need to drink at least eight glasses of water a day. That it's important to drink water before and during exercise.

That coffee and tea don't count because caffeine can dehydrate our bodies. And that you can't trust your thirst as an accurate measure of when you need water since if you're thirsty you're already dehydrated. Well think again. According to a recent review in the Journal of Physiology, most of these accepted truths seem to be myths.

This review looked at the scientific evidence of the 8*8 mantra � drinking at least eight 8-ounce glasses of water a day, and found that there really was none.

The claimed benefits of taking in that much water each day, including benefits for weight loss, bowels, fatigue, arthritis, mental alertness and headaches, losing weight, preventing constipation, are also mostly unsubstantiated.

Other Water Myths That Are Debunked In This Article Include:

By the time a person is thirsty that person is already dehydrated. This in fact isn't true and the best measure of how much water to drink is your thirst.

Dark urine means dehydration. Again that's not strictly true either as there are many other factors that can contribute to dark urine.

Caffeinated beverages dehydrate us. As you'd expect much of this is also unsubstantiated. In fact, contrary to popular opinion, a recent study has found that coffee, tea and sodas are hydrating for people used to caffeine and thus should count toward their daily fluid total.

While this review focuses on the validity of the various water myths, no one seriously disputes that getting enough water is crucial. However, fears of dehydration and the constant barrage telling us we don't drink enough water, has led to a mistaken belief that the safe thing to do is to drink as much and as often as possible. But drinking too much water can be hazardous to your health.

Too Much Water?

The reason why over hydrating can be dangerous is that when we consume large amounts of water when exercising, blood plasma (the liquid part of blood) increases, while the sodium concentration in the body fluids decreases, both as a result of the dilution by the water but also because sodium is lost by sweating.

Hyponatremia, or low blood sodium, generally happens after drinking too much plain water and can lead to adverse effects and tissue damage, and interfere with brain, heart, and muscle function.

Early symptoms can be difficult to spot and include:

Confusion
Nausea
Fatigue
Muscle cramps
Weakness
More severe symptoms can include vomiting, muscle twitching, delirium, seizures, coma and death.

A new review of three deaths of US military recruits highlights the dangers of drinking too much water. Like in sports, the military has traditionally focused on dangers of not drinking enough, especially under conditions often associated with exercise and hot conditions. However, getting overzealous over the need to drink large amounts of water and over-hydrating can have deadly consequences.

So How Much Water Should You Drink.

My recommendation is to drink when you're thirsty, and if you think you should be drinking more, don't overdo it. As far as drinking water in and around exercise, I've outlined a few simple guidelines that will make sure you're well hydrated without hitting any extremes.

Within an hour or so of training, drink a few glasses of water so you start well hydrated. While training you can drink a glass or so of water for every 15 minutes you train, especially if you're sweating it out.

However, even during times of heavy sweating don't take in more than a quart and half of water per hour. As far as how much your daily intake of water should be, The American College of Sports Medicine that 12 quarts is the maximum amount to drink in a 24-hour period.

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Myth: 4. Water Reduces Fluid Retention
Contrary to popular belief, drinking water can actually help you shed excess water weight. When water is in short supply, the body, thinking there's a shortage, begins hoarding it. This water is stored in extra cellular spaces. In other words, your skin starts looking soft and puffy.

Reality: Extracellular water balance is regulated through sodiuim levels. The body does not "hoard water" in times of shortages. If a person retains a lot of water which will usually cause localized swelling there are a host of medical condtions to look at. Dehydration not being one of them. If the healthy normal body hoarded water outside cells just because we didn't drink copious amounts we would be in trouble. It would upset metabolic processes. The reason people shed water when they drink incredible amounts of water is because they lose sodium. Which can be very dangerous. It is not "healthy". If you are not going to step on stage and have not already fucked up your body to the point where you are retaining excess fluid (a medical problem) then it is not good advice to "drink a lot of water to shed water", imo.

One thing that people miss when it comes to fluid reccomendations is not only do all bevergages count but so does food. If you were to set as you goal to take in 2.5 liters of water per day, you could get a whole lot of that from the food you eat. As a matter of fact, the estimate is one mililiter of water per calorie. So 1000 calories can roughly equal one liter of water.
Of course I'm not saying to not drink water I'm just making the point that people don't really realize just HOW MUCH extra water they are taking in when they only count to bottle they are carrying around with them.

Since I know people won't take my word about this myth of "hoarding water" as such I thought I'd post this little thing on the function of the kidneys. I bolded the relevant parts.

The body has two kidneys, each about 4-5 inches in length and reddish in color. The kidneys are located just above the waist, behind the abdominal cavity. Each kidney contains the hilus, through which the ureters are connected. Blood vessels and lymphatic vessels also are connected at the hilus, with the blood entering through the renal artery.

Three layers of tissue surround each kidney. The renal fascia, made of a dense connective tissue, anchors the kidneys to surrounding structures.

The principle task of the kidney is to preserve the volume and composition of the extracellular fluid constant. This it must do despite a varying outside environment, and varying input. A part of this task–but only a part–is to remove from the body some of the waste by-products of metabolism which the cells cannot break down further. Thus the principal function of the kidney is not excretion, but regulation. We can move and live on dry land, even though we are three-quarters water, and survive; our cells tucked away in a carefully preserved ocean of extracellular fluid, whose composition is guarded with exquisite accuracy by the kidneys, a major part of our life-support system in this hostile environment. We can roam into deserts, and (usually) survive, or drink a six-pack of beer, or starve, or gorge, but essentially the extracellular soup remains of a constant composition, and because of this, the composition of the cells themselves is constant.

The kidney is less in control of the intracellular water, since if the kidneys do their job adequately, each cells is largely autonomous, and will extract and eject what it needs or does not need from the extracellular fluid. The kidney conserves what we need, but even more, it permits us the freedom of excess. That is, it allows us to take in more than we need of many necessities—water and salt for example—and excretes exactly what is not required. This is essential, since neither our ancestors nor we, animal or human know the composition of the foods we eat, and the only way to ensure a sufficiency of everything is to eat an excess of at least some. Finally, the kidneys preserve the volume of our body fluids as well as their composition. Given that we’re almost ¾ water, quite simply weighing oneself each day can assess the precision with which the kidney achieves this.

Despite variations in diet, exercise or fluid intake, the figures remain constant. The kidney performs its tasks, with a precision of as good as 1% and never worse than 5%, under extremely varying circumstances. If the kidneys fail suddenly, death occurs after a few days, partly because some of the accumulated metabolic waste products are toxic to the heart, which stops. More interesting, is the way in which the kidney can adapt to slow destruction by dysfunction, so that one can survive on as little as 5% of overall kidney function. The kidney has greater reserve capacity in the face of disorder than (for example) the heart or the lungs.

Why can’t we switch off urine production all together in times of drought? This is impossible because of two constraints. The first is that there is an upper limit to the degree of concentration of urine that we can achieve. This is a function of the length of the loops in the kidney tubules. The other constraint, given that there is a limit to our concentrating capacity, is that there is a minimum amount of soluble waste, which we must excrete through our kidneys each day. This is mostly nitrogen-containing compounds, principally urea; and on a normal diet we produce an amount which will not dissolve in less than about one pint of the most concentrated urine we can produce. Therefore, even on a raft in the ocean, or in the dessert, we go on passing this volume of urine. If you are dehydrated, your urine is already four times as concentrated as your blood.

Excellent info, appreciate it. Sorry so long replying been a little busy. Makes for a very good thread, thanks. I am a little dissapointed that you agree though! ;)


Iron

Hard to disagree with basic phsiology when it comes down to it .

I doubt that the average person who drinks extra water thinking it's going to halt the aging process or make muscles grow is going to hurt themselves, really. But there is a point I could make about drinking tons of water instead of other water containing beverages and that is there are some good things nutrient wise you are missing out on. As far as the body is concerned water is water.

I agree in general that your thirst will guide you. But I would like to caution that there are certain situations where drinking extra water as a precaution...although not extreme ridiculous amounts of it...may be a good idea. When your are sweating out a lot or working or playing in extreme heat it is good to sip on something whether you are particularly thirsty or not. I have seen and have been in situations where the effects of dehydration snuck up on people (including myself) before they were really aware of it.

Edit* I thought I should back that up with at least a little explanation other than personal observation. You'll hear lots of arguments as to when the thirst response kicks in and whether you are already "dehydrated" to some degree but since there is not really a good gauge of what is "normal" then it all becomes a lot of pointless speculation. In general you drink when you're thirsty and your fine. And since most everybody given a choice drinks much more than that plus takes in liquid through food...you get the point.

But the problem when your out in the hot sun our something is that if you are dumping enough fluid and becoming dehydrated quickly enough you may feel a little thirsty at first but the degree of thirst doesn't increase proportionately with the degree of dehydration. I.E. when you are twice as dehydrated you won't necessarily feel twice as thirsty. In certain situations, with strenous effort in extreme heat it is just easy to become dehydrated quickly enough while ignoring the thirst and as you become more dehydrated you're not exactly thinking as straight anymore, so on and so forth.

Anybody who's been engaged in serious work or play in dry or hot conditions (even cold dry conditions) knows it's pretty easy to override the thirst response when you're busy. And as you become more dehydrated your judgement decreases and you can get a little "demented" meaning that thirst isn't so reliable anymore. So it always pays to be careful about hydration. But most of the "hydrate" mania we get today is hype.

Man that's refreshing to hear. I'll bet you won't find another person on any board anywhere that agrees with that. Drinking water has become almost a religion.

I agree, I doubt drinking overly copious (how's that for a word?!) amounts of water will become a public hazard but it's just not necessary. It's a product of ingenious marketing or at least of capitalizing on it.

Carrying a bottle with you everywhere screams, "look at me I'm being healthy!" I get a kick out of carrying a bottle of Cherry Coke (diet of course) around in the gym!

And yeah water is water. It's still H2O regardless of what's it's mixed with! It all ends up mixed up in your gut anyway. Some people think the diuretic properties of coffee/tea cause you to lose more total water than you take in. That's another one. Where's the science on that one??! Some of this stuff is just stupid..

The big point is that you can't cram more water, nutrients, etc. into the cells. Anything more than what the body can use is simply flushed out. Extra amounts don't "flush out toxins." It's not like you can pressurize your body with water to force flush toxins out like a automobile radiator. But to most people, it makes sense so they buy into it.

Definitely agree that if you're out in excessive heat and are working, exercising or whatever that you do need to force fluids some. I've had the same thing happen to me as well. I've also noticed that on days like that I can drink what seems like gallons and never have to pee. I'm using all I'm consuming. You may dehydrate quicker than your thirst can keep up. Obviously in exteme cases you can dehydrate and actually die while drinking all you possible can. So you do need to be careful.

Yeah, water is big business. Everybody and their mother offers bottled water. What does yogurt and water have in common? They are both sold by the same company.

I haven't done tons of reading on the caffeine thing because, frankly, I don't care. But from what I've read it seems that yes, there is a diuretic effect for some people who are not used to it. But it is not so extreme as to cause it to be "anti-water". And for people who are used to it, drinking coffee or tea on a daily basis, they don't seem to lose any hydration from it. But I'm not speaking from the standpoint of intensive reasearch. I believer the review we posted speaks specifically to what I just said, though.

Did you know that it's against the law to sell spring water ?

It's the bottle that they sell, the water is free....

Now that sounds like a water myth .

That sounds weird. You can't put something in a container meant for consumption and then say it's free if you pay for the container...it's semantics. Because that would mean you wouldn't have to meat FDA labeling requirements. Since bottled water falls under the regulation of the FDA in the US if there is such a law it's a worthless one.

It's actually considered a "packaged food product". That's why it falls under the FDA as opposed to the USDA or or the EPA in the case of tap water. Each state has it's own guidelines, permits etc, though and in some cases it's handled by their agriculture departments...but it's all overseen by the feds (although I'm not saying that it's overseen well, necessarily).

Heck, 85% of water companies are members of the IBWA which is an independant organization where it's members submit themselves to even stricter guidelines than the government. Sure is a lot of trouble for something you're giving away .