SubscribeThe Mythical Daily Water Requirement
8 glasses - that's what most people think they need as a daily requirement. Copious water intake is supposed to keep organs functioning properly, skin supple and body weight at bay. Nonsense! - say researchers from the University of Pennsylvania who conducted a study to test these theories (which will be published in the June issue of the Journal of the American Society of Nephrology).
We all know that our bodies need water, but nobody quite knows exactly how much. Let's take a look at where this misconception began, shed some light on water and hydration and look at some more realistic water goals.
Let's be clear on something right out of the shoot. Water is the hub of all chemical processes in the body and the king of all nutrients. We should be drinking it daily. But where did the 8 glasses per day gospel originate?
Dr. Frederick Stare suggested this theory in a book "Nutrition for Good Health" published in 1974 ("theory" being the operative word). The theory caught on despite its arbitrary origins and it has been speculated that bottled water companies are largely responsible for perpetuating the 8-a-day mantra.
Water Intake - Not Just From Water
Counter to what I've just presented, we actually DO need at LEAST 8 glasses of water per day. But here's the catch: This intake is satisfied not only from water intake, but also from other fluids, the food we eat and the metabolic processes required to break down that food.Juice and milk contribute to hydration and (surprisingly enough) so do caffeinated and alcoholic beverages. I probably don't have to tell you though, that alcoholic beverages are not recommended to help you meet your fluid requirements. Regarding caffeine - many people still believe it causes dehydration, however studies as early as 1928 have shown otherwise.
The fluid from food and its accompanying metabolic action alone can account for as much as 6 glasses of water! Water is the best fluid - no argument there, but don't get caught up in the absurdity of forcing down extra glasses of water if you have a coffee.
Water - Too Much of a Good Thing?
The more the better does not apply to even the mighty water. Consider that 31 runners in the 2000 Houston Marathon were treated for hyponatremia - a condition that can arise with excess fluid consumption, causing a dilution of sodium in the blood. This has prompted a revision of previous guidelines which have changed from "drink as much as you can tolerate" to "drink as needed, but do not exceed 800ml per hour"Estimating water needs
- There is a large variation when it comes to individual water needs. Those who are active have increased water requirements, especially if exercising in hot weather.
- As a baseline, 1L of water a day (about 3 glasses) should be fine for those individuals who are relatively sedentary.
- Increasing water intake to 1.5-2.5L/day (4-5 glasses) per day is a good idea if you are moderately to highly active, and drink a few gulps every 15-30 minutes if exercising in hot weather.
- If you are exercising for longer periods of time (going on a long hike, as an example), be sure to consume some salt when consuming large quantities of water.
- If fat loss is your goal, make water your primary beverage - aim for 75% of your fluid consumption, while cutting back on juice, pop and other calorie-containing liquids.
In Closing
Let's face it, most of us would probably benefit by drinking more water for the simple fact that it replaces other caloric and otherwise unhelpful fluids. Drink water whenever you can - try to have a glass with each meal, and consume it while you are exercising. Use common sense when hydrating during exercising - especially in hot weather. You need not, however count empty bottles, or stress if you fall a glass or two short of your daily "requirement".
References:
- Stare, FJ, and McWilliams M. Nutrition for Good Health. Fullerton, CA: Plycon, 1974, p. 175
- Grandjean, AC, Reimers KJ, Bannick KE, and Haven MC. The effect of caffeinated, non-caffeinated, caloric and non-caloric beverages on hydration. J Am Coll Nutr 19: 591-600, 2000.
- Tufts University Health and Nutrition Letter. New Consumption Guidelines for Water Sodium, Potassium. April, 2004
- THE PHYSICIAN AND SPORTSMEDICINE - VOL 31 - NO. 7 - JULY 2003. New Hydration Recommendations.
- Casa DJ: Proper hydration for distance running: identifying individual fluid needs. Available at http://www.usatf.org.
- Weinberg, A, and Minaker K. Council of Scientific Affairs, American Medical Association: dehydration evaluation and management in older adults. JAMA 274: 1552-1556, 1995
I know I need lots of water. Probably relates to the amount of exercise I do, but I normally consume 10+ cups of water every day, usually more, and if I don't I feel like crap. (For cardiovascular exercise over 2 hours at a stretch, I take in electrolytes, too.)
ReplyGlad to read this. I've always been frustrated by the "drink more water" mantra. There've been precious few studies to back it up.
That being said, water should definitely be the beverage of choice -- when one is thirsty.
Replythat makes me feel better. after 8 glasses of water, its close to midnight and the water starts tasting weird... i have several other fluids throughout the day besides my 8 glasses of water, it makes sense to me to not require this much- generally, i've stuck to 4 8oz glasses plus whatever else i have ad that seems enough
ReplyPersonally, I drink at least eight glasses of water most days and usually more. I hate feeling like my mouth is dry, so I always have my trusty one quart water bottle to keep that nasty sensation at bay. Health is secondary in this realm.
ReplyMaybe it's my activity levels, but I've always felt the guidelines were spot on...for me. I like to sip throughout the day, and when I can't for whatever reason, I my lips get chapped and my skin gets dry. Then there's the thirst! And the fact that I feel more alert when I have regular glasses of agua.
I don't drink soda or anything like that, though, so it's not like I'm padding my levels.
ReplyGreat points, and great debunking, Mike.
Like Katie, I naturally drink a lot of water -- my mouth feels dry if I don't (and I notice that I get grumpy!) This has only been the case for the past couple of years though, and I think is tied in with taking more exercise. I get through about 500mls in the gym, and need a glass of water after cycling to work or home from work, but also seem thirstier during the rest of the day.
Anyone else find that exercise makes them thirstier in general?
Ali
ReplyMost people don't drink enough as it is or eat fruits and vegetables that have water inside....so for the general public "drink more water" is usually spot on.
ReplyMike OD - IF Life --
That's an interesting point. I'm definitely less thirsty when I've been eating a lot of salads or soups.
When I'm not being good to myself and relying on easy-to-store-and-grab dense foods (breads, snack foods, nuts, cheese, etc.) to meet all my calorie needs, I am thirstier.
ReplyWhile you have a point, some of us eat just fine and prefer to drink a lot of water. Most days, I eat several servings of vegetables at every meal and I still can go through at least two quarts of water every day.
ReplyThank goodness, I always thought the "8 glasses of water" challenge was similar to eating 72 Oz of steak at a sitting.
I'm sure it can be done, but dang it's a lot.
ReplyHaha.. Red - ever see a movie called "the great outdoors" with John Candy? Your post immediately reminded me of that scene where he devours the "old 96'er".
Replywow, this makes me feel like I am drinking so much! I go through 4-7 32oz Nalgene bottles a day (depending on how hot it is). I am a distance running on my college track and cross country teams, so perhaps it's because of my high activity level (that and I do really sweat more than normal, I think)and my penchant for salty things. I've never really experienced any negative effects either. And I only drink water, and an occasional gator aid after a very hot and long workout.
ReplyGosh, what a cost to the environment that is... all those bottles... why don't you have one bottle and refill it?????
ReplySandy a nalgene bottle is just that a refillable bottle for liquids.
ReplyI always drank water according to urine color. Too dark? Drink more!
So I need 8 glasses a day.
ReplyThat's exactly what I do. I go by urine color usually.
ReplySame here. I run 5K every morning, so I generally drink about 32oz in a 90 minute span. The fluids run pretty clear at that point :) After that, I sip on another 32oz's for the rest of the day.
ReplyConsidering that they always say "8 8-oz glasses", that's really not all that much if you consider how big some glasses are. I fill a 1 liter Nalgene bottle with water and ice and sip on it at work and I fill it again to sip on while I drive home. Plus, I eat a lot of veggies and fruits that have lots of water in them, so I think I get plenty of water during the day.
I also drink diet soda, which I know isn't the best beverage option, but it's kind of obnoxious to me that the Coca Cola company now markets its beverages as "hydrating" and how they can help you contribute to getting your 8 glasses of water a day. I don't usually count soda towards my daily consumption of water.
ReplyPlease make sure you don't use your Nalgene bottle in the dishwasher or wash with really hot water. Also make sure when washing you are not creating deep scratches. Also make sure to be drinking fresh water (not sitting in a hot car for a few hours)--These hard plastic bottles are made with bisphenol A, which your body thinks its estrogen. For more info look up "bisphenol A" or "endocrine disruptors".
ReplyTrust me...I take care not to expose my bottle to very hot water, I never freeze it, and I don't ever leave it in a hot car or anything like that. I wash it with mild detergent in warm water and rinse it thoroughly to keep it clean, but it's just like any other polycarbonate plastic...keep it away from extreme temps.
ReplyI drink closer to a gallon of water a day.
Now, one might argue that that is way too much, but that is the level at which I feel good. Bear in mind, I'm still around 75 pounds overweight.
But drinking the water, I don't feel my eyes to dry out as much, my elbows don't need moisturizer applied hourly, my urine is not too dark and I just generally feel better. I do live in a dryer climate... and one that gets good and hot in the summer. I'll probably be drinking a bit more then!
I do count my green tea towards this consumption though.
ReplyI've heard that for every 25 lbs overweight that you are, you need to add 8 oz on to the 64 oz daily rule. So for you, drinking all that water is probably pretty spot on. I know that for me, it depends a lot on what I'm doing that day as well as whether or not I've eaten lots of salt. Anytime I eat salty things, I get SO thirsty and I tend to drink a lot more.
ReplyI've noticed that if I don't drink 2.5 to 3 liters a day, my gout rears up and whips my ass. I think it lurks in there, waiting and watching, and that one freaking time I only have 2 liters water, and then it strikes.
Sometimes I think it thinks I slept with it's wife.
Anyway, I drink a ton, but with a lot more activity these days it works.
ReplyI always have much better skin when I'm drinking a couple of litres of water daily. You can save a lot on moisturizers by drinking water - I'm sure Procter and Gamble, etc. would rather we not figure this out!
ReplyThe 8 glasses a day requirement was always bogus. Dr. Stare probably just estimated how much he drinks in a day and wrote that in. But think for a second. Do animals drinks a preset amount of water just because? No! They drink when they're thirsty and eat when they're hungry. Drink when you're thirsty is my rule.
ReplyThat is definitely an interesting post. It is tough to gauge standard water intake for people as everyone is different and has different body sizes. I think a more practical rule should be water requirements based on weight as I am sure being that someone who weighs 200lbs compared to a 130lb adult would both have different water requirements.
ReplyWhether or not the "8 cups" mantra is bogus, publicizing a debunking of it is not a public health service in any way. The fact is most people are chronically underhydrated (especially in a society which makes a habit of routinely consuming a cupful of strong diuretics every morning), and could stand to increase their intake of water. The message given should be:
Reply"people in general should be drinking more water than they are", not "the previous recommendation was too high".
Yes, I totally agree. I recently saw an article on NPR that basically told people they don't need water. One of the doctors claimed that a no-calorie beverage such as diet soda is as beneficial, which I believe to be bogus, considering all the other additives, the low pH (this worries me because of my acid reflux), and the diuretics.
ReplyAnd, when I don't drink enough, I get similar symptoms to everyone else: my skin becomes more dry and more acne-prone, my lips chap and my urine becomes an icky dark color and smells like total cereal.
For me this is not true because if I only drink when thirsty, I tend to get dehydrated. I don't know if something's wrong with my thirst mechanism or what, but I have to go by urine color as others have mentioned. Usually it's around 64oz a day or more if it's hot or I'm exercising intensely.
ReplyI've tried the 64 ounce deal before, and had positives and negatives. My acne cleared up, my appetite all but disappeared, but I felt TERRIBLE. I halved it, and felt much, much better.
ReplyYeah...almost any hypes are usually started by the big companies but yes, water on the other hand is really important if you are on a workout program.
ReplyI found a 2002 scientific article that supports Mike Howard's position on water intake. I blogged about it in February this year: http://advancedmediterraneandiet.com/blog/?p=16
"Eight glasses of water a day" falls into the category of urban myth. Unless you're digging ditches with a shovel all day under the hot sun in a desert...
-Steve Parker, M.D.
ReplyI was interested by the 'drink water with each meal' bit - I read research somewhere that said we should not drink water within 30 minutes of eating because it dilutes our digestive juices - anyone have any thoughts on this?
ReplyCari
Hi cari,
From Mayo Clinic Gastroenterologist Michael Picco:
"No. There's no concern that water will dilute the digestive juices or interfere with digestion. In fact, drinking water during or after a meal can actually improve digestion. Water and other liquids help break down the food in your stomach and keep your digestive system on track. Looking for other ways to promote good digestion? Focus on a healthy lifestyle. Eat plenty of fruits, vegetables and whole grains. Maintain a healthy weight. Include physical activity in your daily routine."
ReplyI think that drinking at least 64 ounces of water a day, up to 1/2 your body weight in fluid ounces (if you weigh 300lbs, drink 150 ounces) is a very effective tool for weight loss and improving your health.
In "Your Bodies Many Cries for Water" Dr. B explains hundreds of examples of people improving their health just by increasing their water intake, and he says it is natures best appetite supressant.
I lost 130 pounds and have kept most of it off for 14 years. I totally credit drinking water throughout my day as one of the cornerstones to my success.
It amazes me that products like Vitaminwater and diet Coke claim to be good for us or for our hydration needs. In a day when obesity is quickly taking over as the biggest contributor to disease and premature death--why NOT choose water?
We know it won't hurt, many agree it will help and until you drink enough to know, you just won't know what you are missing!
Respectfully,
ReplyJulia Havey
www.ViceBusting.com for a free audio of "Secrets of the Fittest"--on it drinking water is one of the secrets!!
I think that drinking at least 64 ounces of water a day, up to 1/2 your body weight in fluid ounces (if you weigh 300lbs, drink 150 ounces) is a very effective tool for weight loss and improving your health.
In "Your Bodies Many Cries for Water" Dr. B explains hundreds of examples of people improving their health just by increasing their water intake, and he says it is natures best appetite supressant.
I lost 130 pounds and have kept most of it off for 14 years. I totally credit drinking water throughout my day as one of the cornerstones to my success.
It amazes me that products like Vitaminwater and diet Coke claim to be good for us or for our hydration needs. In a day when obesity is quickly taking over as the biggest contributor to disease and premature death--why NOT choose water?
We know it won't hurt, many agree it will help and until you drink enough to know, you just won't know what you are missing!
Respectfully,
ReplyJulia Havey
www.ViceBusting.com for a free audio of "Secrets of the Fittest"--on it drinking water is one of the secrets!!
In my experience, the more water I drink on a regular basis, the more I crave water throughout the day. It's hard to go from drinking little to no water to drinking 64 oz; but if you gradually increase your intake, it seems to work better. I don't think there's any such thing as drinking too much water in general, but it's definitely not good to drink too much at one time. I've heard that 4oz per 15min is the fastest your body can absorb water, but I'd like to hear more about that.
ReplyThanks for your post. I'm linking to you from my article on water.
Thanks
Reply