Is 8 Glasses of Water Per Day Overkill? 90
An anonymous reader writes: "David Harris reports in his science news that the American Journal of Physiology today published a study dispelling the 8x8 myth. That is, the recommendation to drink 8 eight-ounce glasses of water per day has no scientific evidence behind it. The paper also mentions the risks of drinking too much water and explodes some other urban myths of water drinking such as the 'thirsty means dehydrated' and 'dark urine means dehydrated' myths."
I just KNEW it!! (Score:1)
Re:I just KNEW it!! (Score:1)
I typicaly glug down quarts or half gallons of fluid at once, err, heh. a few 8oz glasses of water at once? Nothing to it.
Light on content (Score:2)
For once, the /. article summary says nearly as much as the linked-to articles themselves. It's funny, no matter how hard I try to challenge preconceived notions I have, there's always one more "well-known fact" I forget to look into.
caffeine/alcohol (Score:4, Interesting)
Re:caffeine/alcohol (Score:4, Informative)
Re:caffeine/alcohol (Score:3, Informative)
It's also a "well known" fact among hikers and campers. But then, this article is about breaking myths.
--
Evan (no reference)
Re:caffeine/alcohol (Score:2)
Re:caffeine/alcohol (Score:1)
Re:caffeine/alcohol (Score:2)
WRONG! (Emphasis added because this is important).
Ecstasy just makes you feel thirsty, and tends to block the "okay, I've had enough water now" signal, so you keep feeling thirsty.
Locally we had a 16 yr old girl go into a coma and die because of this. Took ecstasy, got thirsty, kept drinking water until she'd basically OD' on the stuff. The increased fluid volume caused cerebral swelling which induced the coma which she never recovered from.
The friends that supplied the drug to her were charged, don't know what the current status of the case is.
I suppose if you "know what you're doing" (although I question that assessment of anyone who voluntarily takes mind-altering drugs of unknown provenance) you can alleviate the thirst sensation with small sips without overhydrating. She didn't, nor did her friends.
Re:caffeine/alcohol (Score:2)
And no, it isn't caused by getting a bad version of Ecstasy, it is a known, and documented side-effect of the drug.
Yeah, it's a known, documented side-effect of alchohol, too. So?
Re:caffeine/alcohol (Score:1)
Pay to view article. (Score:2, Funny)
Re:Pay to view article. (Score:2)
I think your puns are all washed up. (n/t) (Score:2)
Glasses of water? (Score:2)
I might have to re-evaluate my daily drinking.
Re:Glasses of water? (Score:2)
*sigh*
that seems pretty accurate to me. (Score:1)
Re:that seems pretty accurate to me. (Score:2, Informative)
There's pretty close to 12 ounces of water in a 12 ounce can of soda, but with caffeine you'll probably pee out 14 ounces.
Re:that seems pretty accurate to me. (Score:1)
Re:that seems pretty accurate to me. (Score:1)
Re:that seems pretty accurate to me. (Score:1)
That's it for maybe 9 days out of ten. not one drop of plain water, and at most 44 oz of other liquids (of which 32oz has diuretic properties). So either I'm getting the other needed 20 oz from the food I eat, or I guess I should have evaporated into nothing years ago.
Maybe when I'm sixty I'll discover that my kidney's have given out but I doubt it. Humans evolved on the plains of Africa, not a place known for having a half gallon of potable water for evey individual available every day. It was also much hotter than the typical North American living in air conditioned buildings is typically exposed to. Given that I expect that I will be fine.
Of course if I am going to be outside on a hot day I drink more fluids (even actual water on occasion) as I am going to sweat it out, but I don't sweat substantially in 70degF room typing at a keyboard.
My guess is the 8 glasses a day recommendation, if it was based on any kind of science, came about prior to the wide availability of AC, and when most people worked in jobs that required using muscles others than those that move their fingers, wrists and eyes.
Clear Evidence (Score:2)
NPR has the interview (Score:3, Informative)
Guest host Renee Montagne talks with Dr. Heinz Valtin, doctor of physiology and professor emeritus at Dartmouth College, about a new study saying that people may NOT need to drink eight cups of water a day to stay healthy.
story on npr.org [npr.org]
Lets hope they got over the deep linking craop.
It's old news, but myths are hard to kill (Score:2, Informative)
Water - the myth of 8 glasses [canoe.ca] (February 13, 2001)
How much water do we really need? [cnn.com] (May 24, 2002)
shallow literature searches (Score:1)
Do the Physiologists have amazingly deep databases, or is something funny going on here?
Re:shallow literature searches (Score:1)
Nearly 100 years! Wow!:-)
The old saying tht `Americans think 100 years is a long time while Europeans think 100 miles is a long way' is clearly true.
(OT) 100 miles vs. 100 years (Score:1)
The old saying tht `Americans think 100 years is a long time while Europeans think 100 miles is a long way' is clearly true.
I can walk 100 miles within four days. Ten bucks says I'm not going to live 100 years, and most of you won't either. This is why life + 70 year sentences [pineight.com] are too long.
Re:(OT) 100 miles vs. 100 years (Score:1)
Re:shallow literature searches (Score:1)
I know your being funny, but psycology doesn't go back much further than 100 years...
Stupid (Score:2, Insightful)
You are orders of magnitude more likely to experience dehydration than to experience the almost mythical "water intoxication." (Yes, it is possible to kill yourself by drinking too much water, but it happens very very rarely.)
So ignore this article and go have a nice glass of water.
Tim
Re:Stupid (Score:2, Insightful)
Drinking water is good for you. Drink lots of water.
Based on what evidence? I've always thought 8 glass of water thing was a crock.
When it is hot, humid, and I am outside, I can drink that 64 oz of water within an hour or less. The people who don't drink enough water get taken away in an ambulance.
Well, duh, obviously when it's hot and humid you need more water. But that's not what we're talking about. Under normal circumstances, you get more than enough fluids from the food you eat. Excess water/fluid just gets pissed out.
Re:Stupid (Score:1)
Along with various toxins.
Water helps to move toxins through your kidneys. Without "too much" water you wouldn't need to use the washroom, meaning you'd never urinate out those toxins, which common sense tells us is bad.
Re:Stupid (Score:2)
Re:Stupid (Score:1, Offtopic)
Trust me, you'll thank me later.
----
Which reminds me, I just bought Dr Strangelove on DVD, and haven't had a chance to watch it yet.. I'll have to make time tonight.
Re:Stupid (Score:2)
(The latter is important at altitude, which tends to thicken the blood anyway.)
Re:Stupid (Score:1)
Re:Stupid (Score:1)
dilutional hyponaetremia (Score:3, Interesting)
Re:Stupid (Score:2)
But yes, dehydration (especially around these parts) is more likely.
(BTW, if you happen to be female and pregnant, (or male and pregnant I suppose, but that's very very rare
Re:Stupid (Score:1)
Now wait a second! (Score:2)
Partially switching from Diet Coke to Water (Score:3, Interesting)
A friend I respected suggested that I consider drinking more water and less soda. He claimed that I would lose weight (I was 265 pounds at the time) and feel better.
What I discovered is that I did lose weight, although not enough to significantly impact my appearance, but more to the point I felt better - I was generally more alert in the afternoons, and after a while just a few sips of a Diet Coke would give me more energy (when I needed it) than a whole one would previously.
It looks like caffinee becomes steadily less effective as more of it is used, so the simply exponent of abstaining from it and limiting its intake worked well.
So I would recommend something like this to anyone trying to become more healthy. I started losing weight at a good clip, incidentally, when my new job responsibilities made me less sedentary. Annoying but good for me in the long term.
D
Re:Partially switching from Diet Coke to Water (Score:3, Interesting)
As far as losing weight goes -- I've heard that caffeine affects your metabolism such that it kicks blood sugar levels temporarily higher. This would do two things -- the higher blood sugar level prompts conversion of the sugar to fat, and when it drops again, it makes you hungry. That in turn would tempt you to eat more, and so on.
I know I tend to eat less when I drink water rather than my usual several cans of diet pop (alternate Diet Coke and Fresca -- I don't need that much caffeine).
Re:Partially switching from Diet Coke to Water (Score:1)
I've personally noticed a lot of other benefits from drinking water over sodas, other than the weight factor like you've discovered. I've had an easier time concentrating on tasks, for example. Have you ever gone an extended period of time (like 6 hours or so) without a drink of water, then finally take a chug? I swear you can feel your cells getting immediately replenished like a dried up plant getting watered.
Literature reviews get you on NPR? (Score:1)
Now, if this was an article reporting on a study that followed the general health and well-being of a number of participants over a certain period of time, relating health to water consumption, with a control group given a placebo of, say, Mr. Pibb or something, then I would be a bit more inclined to read on beyond the abstract.
If literature reviews get you a publication in the Journal of Physiology and a spot on NPR, then I think I'm in the wrong line of academic inquiry.
Roll on tenure!
it was never "drink" 8 glasses... (Score:2, Informative)
You can get water from sources other than just a glass of water - for instance, all those servings of fruit you never eat.
The article has one note of accuracy... (Score:1)
(Disclaimer: I am not a doctor)
The whole 64 oz per day thing is a bit off, but here's why: water intake should actually be proportionate to body weight, but a surplus isn't necessarily a bad thing. Increase per caffeine intake (diuretic effect counteraction) and per physical activity increase (like Camelbak [camelbak.com] says, "hydrate or die").
For instance, if a 150 lb random were to drink 64 oz of water over the course of 1 day and spend the day sitting in front of his computer, they would be well hydrated and urinating fairly frequently as a side effect. (They would be lethargic due to caffeine withdrawal, but they would be very well hydrated.) If the same 150 lb random ran a marathon and only consumed said .5 gallons of water over the course of the run, they'd be cramping from heat exhaustion by mile 24. (Seen it.)
Now take a 300 lb random. If they spent the day in front of the computer and gave them 1/2 gallon of water to drink over the day, they'd be particularly thirsty to the point where they would feel dry. Increase the water intake and they'll feel better. And if your random is running a marathon, that 300 lbs better be muscle lest he wear himself out despite proper hydration.
(end disclaimer section)
More data can be found by doing a google search [google.com], natch.
Agreed... try this formula instead (Score:1)
(body weight in ounces) / 2
The formula gives you a more optimal amount of water for your weight. For example, a 150-pound man would drink 75 ounces of water per day. Adjust the number based on your activity level.
Also, you should drink the water gradually throughout the day. Drinkin a bunch of water all at once won't help you that much. Your kidneys will just remove the excess water from your system to maintain osmolarity and plasma levels.
Re:The article has one note of accuracy... (Score:2)
But the most important thing to note (I think) is that under normal circumstances the body's thirst mechanism is entirely sufficient to prevent dehydration.
customary quotes...Water sucks...gatorade's better (Score:1)
Medical Geek Speaks Out (Score:5, Informative)
2) It is true that "being thirsty means you're already dehydrated" is an exaggeration, but it is an intentional one. It means "you're well on the way to being dehyrated". The exaggeration is, I suppose, intended to catch ID10Ts who ignore thirst even during 10-km runs in 110 degree weather. Thirst does kick in well after you have lost plenty of fluid, and once ADH (anti-diuretic hormone, the hormone that controls urine production and volume status) has already risen. These facts, I suppose, are the origin of the common anecdote.
3) "Dark urine doesn't mean you are dehydrated" -- not true. It *is* true that it is difficult to judge from color alone. Despite our 16 million color resolution, it is hard for people to subjectively grade color without experience (i.e. working in a urinalysis lab); thus, judging hydration by urine color alone will have a high error rate and often be inconclusive. Other factors, such as urine contaminants, might make the test less accurate. Along with other clues, however (i.e., being sweaty, thirsty, and tired), it may be useful.
4) "Water intoxication", a peculiar form of hyponatremia (low blood sodium concentration), is *not* mythical. However, it *is* much rarer than dehydration. It takes a special kind of person (read: mentally ill patient) to drink the 25+ glasses of water per day that it requires to achieve this.
5) Studies have shown (sorry, I don't have links, its 0130 around here) that caffinated beverages such as Coke hydrate at about 2/3 the rate of pure water. That is, at Coke concentrations, the caffeine dose is sufficient to cause you to lose 1/3 of the water you just drank as part of the Coke.
6) These indicators -- thirst and dark urine -- are not "myths" and not useless (although they are far from perfect). I happen to know first-hand that some of the best doctors in the United States use these observations in their daily assessments of patients.
7) "Absence of evidence is not equal to evidence of absence." --paraphrased from Carl Sagan
This fellow has done very little experimentation on his own, but simply collected the lack of research combined with evidence from his own student experiments over the years. While this is a provocative article, it is intended to stimulate research, and NOT to be the definitive work on the subject. What's needed (as he states at the end, in A CALL FOR DIALOGUE) is more and better (and better funded, pretty please)nutritional research!
Disclaimer: IANAD (but I am in medical school and work with 'em in hospitals every day; see address.) And yes, I am a geek. Been programmin' since age four (BASIC on a c64), researchin' at MIT. Good enough for youz?
Bzzzt!! And NO thanks for playing (Score:1, Flamebait)
2) Depending on how one quibbles over the meaning of dehydrated and thirsty, various correlations can be supported.
3) In other words, there are so many variables and exceptions, that dark urine doesn't mean you are dehydrated.
4) In other news, eating 25 pounds of food at one sitting can be hazardous to your health.
5) Further revelations show that alcohol is also a diuretic.
6) Certain myths are not myths as long as you account for the 1001 exceptions and variations that make them hard to pin down.
7) Just because you didn't cite any references other than your self-proclaimed "medical-geekness" doesn't mean there are no references, therefore we should trust you.
And just how much experimentation on your own have YOU done as a medical student?
Nope, not good enough for me. Go exhibit your ego elsewhere.
Ignore the negative replies... (Score:1)
Re:Medical Geek Speaks Out (Score:2)
i think i was once intoxicated by water. with 2 friends, i drank 4 liters in 20 minutes. it was a contest to see if we could do it and who could do it fastest. the contest was spurred by the fact that our H.S. chem lab had 4 litre 'battery jars' that we cleaned out and filled with water. my friends finished in 15 minutes but puked it all back up within 10 minutes. i kept it down but and pissed it out during many rushed trips to the bathroom over the next 2 hours.
anyway, i think i was feeling a bit 'drunk' but it could have been the insanity which was apparently controlling me at the time....
p.s. drinking that much tap water is very hard to do -- after the first litre all you can taste is chlorine and you gag before each sip! so it's really not any fun.
Re:Medical Geek Speaks Out (Score:2)
Re:Medical Geek Speaks Out (Score:1)
I want this for my new sig! What's the source of the quote? Thanks.
In my climate, absolutely not. (Score:1)
If you don't want to get seriously sick here, you must drink mass quantities of water. My first visit to New Mexico was a hiking trip I took when I was fourteen. The rangers recommended eight liters of water a day, which probably was overkill--but not by so much as one of my companions thought, who ended up spending a night with some pretty bad nausea from the altitude and lack of humidity.
It's true that you might not need quite so much in less extreme climates, but it's a great deal harder to give yourself water intoxication than to get dehydrated. Besides, it gives you an excuse to get away from that accursed keyboard.
drink til you pee white (Score:1)
forget the 8 glasses a day thing. listen to your own body talk.
Re:drink til you pee white (Score:2)
Usual color scale:
Clear.. okay.
Light Yellow.. okay..
Thick lemonaide yellow.. drink water..
Tang Orange.. Someone slipped me some pyridium.
Red.. time to see the doctor
White.. WTF?
Re:drink til you pee white (Score:1)
For those of us with a metric upbringind (Score:2)
After this story, and one yesterday aboutt he size of drinks cups also in ounces, I've looked up the conversion rates to see what you're all talking about
from this web site [eserver.org] :
1 American fluid ounce = 29.57 millilitres.
1 British fluid ounce = 28.41 millilitres
So the American 8oz cup is just under a quarter litre (or around halfway between a 1/3 and a 1/2 English pint, if that's more your kind of reference size....)
Other dangers (Score:1)
So that's what happens! Guess I'm not thirsty now.
-Ed
docbrown.net [docbrown.net]
Graphic Design, Web Design, Role-Playing Games...all the good stuff
Hyponatremia dangers (Score:1)
8x8 may still be a good idea, but relieving yourself from all that water is just as important.