Saturday, June 10, 2006

How much water should we drink?

I was leaving the gym and thinking about water consumption. On my way out, I thought about the amount of water that I drank during my workout. It was about a 1/2 liter and then during the day I'd had maybe 6 glasses. Even if you're not thirsty, do you have to consume 8 glasses of water a day? And how much water is 8 glasses? When I went searching for an answer it was difficult to find one. A CNN website says the question is simple, but there isn't an easy answer. Some nutritionists say you should drink 8 glasses, but how many ounces is that? Others say that you should drink half your body weight in kilograms. There are even some nutritionists that say that you should only drink when you're thirsty.
The interesting thing about the water question is that the health arena has been for a long time, and in my estimation, still is a realm of urban legends. Health care essentially revolves around revisited and revised urban legends. Take the case of leaching and bloodletting (see a link to a history of bloodletting below). Bloodletting was used as a treatment for fevers and other things you can read about, but the point is that it was basically an urban legend about health in its day, but not entirely without its uses. Today leaches are still legitimately used for some treatments, but because of scientific advancements we can know what they are precisely capable of doing for our health. How will we look at water intake in 20 or 30 years? Will the traditional vague advisement of 8 glasses be outdated very soon? What do people think about the debated water question? CNN has a site that reviews some of the factors you should consider when calculating water intake. Take a look. Water intake , Bloodletting


Blogger A.Marie said...

My major is Public Health, and last semester I took a class on Nutrition for Atheltes. The class really emphasized the importance of water consumption for athletes, and the population as a whole. As you all have probably heard, our bodies are about 75% water... that fluid is used to keep every cell in our bodies from rupturing (and cells themselves can be up to 90% water), to maintain apropriate internal body temperatue, to cushion our organs... it has a thousand different purposes.
So for the question about necessary water amounts, I turned back to my textbooks rather than the internet, which often offers widely-varying advice. Sure enough, 3 out of 3 of my nutrition textbooks argue that the average person needs about 64 to 80 ounces of water per day. That's two large Nalgene bottles or 8 10-oz. glasses, throughout the day. Of course, the term "average person" is sort of vague, but it is assuming that you are not an athlete or participating in much high-intensity exercise. If you are (or even just working out at HelWel), you need to up your water intake. Some athletes need to drink almost twice as much water as the average person, especially for endurance tasks like a marathon or a football game, and for recovery. But even the average Joe would not be harmed by drinking more water every day.... most of us don't get enough as it is, and there is really no such thing as drinking "too much" pure water. The issue is complicated, though, as many factors affect the amount of water a person needs. Activity, temperature, and personal physiology (ie how much you sweat is different from someone else) make it difficult to pinpoint am overall recommendation. But some tips to help you monitor your body's needs:

1- DO NOT wait until you feel thirsty to drink. Thirst is one of the LAST symptoms of dehydration. You should sip water pretty continuously throughout the day. It doesn't mean you need to carry a huge Nalgene bottle to work (although there is no problem with that, either), but just be sure to stop by the water fountain every now and then. A lot of little sips add up.

2- Try to hydrate with WATER, not diet sodas, coffee, tea or sports drinks. The caffeine and sugar content of these drinks is not healthy in high amounts. You can still drink them in moderation, but do not rely on them for complete hydration.

3- If you are working out, or it is a particularly hot day, DRINK MORE WATER! You may not feel it immediately, but the affects of dehydration can cause you to feel irritiable, tired or have headaches later on. So during times that are more stressful on your body (like hot or active times), be sure to drink up.

4- Check yourself. Are you tired? Irritable? Munching for no reason? A lot of the time, people grab food when what they really need is water. Try it next time you're about to eat for no reason. Just drink a glass of water and see if that urge to chew doesn't go away. It's a cool trick. Also, two good markers of dehydration are headaches and your hands. If you look at the palms of your hands and they look pinkish and spotty, you need some water.

That was long, but there is not short answer to how much water EVERYONE needs. Our bodies, activities, and environments differ so much that all you can really do is follow your own body. And a rule of thumb is to just keep sipping, because it's next to impossible to drink too much water.

8:00 AM  
Blogger Matt Jacobs said...

A. Marie definately makes good points about athletes need to drink water but not many people take into consideration the possibility of drinking too much water. As a distance runner, I have spent a good deal of time researching the different factors than contribute to my ability to maintain a certain amount of energy throughout long distances and one of the major factors is hydration. One thing that runners have recently been learning about (usually Marathoners)is hyponatremia, or overhydration. This subject was brought to peoples attention when a runner in the 2002 Boston Marathon, Cynthia Lucero, collapsed and died at the 22 mile mark. Hyponatremia occurs when a person intakes more water than they loose (sweat or urination). To know the true amount of water that anyone should drink, a runner should weigh themselves before and after a run to see how much water their body looses/retains. The TRUELY APPROPRIATE amount of water anyone should drink varies widely on a person to person basis.

Just in-case you are a runner, never drink more than 16-24 ounces of fluid one to two hours before a race and only drink 8 ounces for every 30-40 minutes of running...

Talking about the nuances of fluid intake as A. Marie and I am doing is really only relevant and widely known to atheletes but I agree with Hillary that the amounts of water that people are told to drink, in general, are solely based on word of mouth.

7:26 PM  
Blogger Evelyn said...

I kept hearing that too much water can kill you but I never knew that it was true, I thought it was one of those myths....but good to know.

5:00 PM  

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