We’ve become a nation of water drinkers, so bitten by the bug to imbibe that we lug plastic bottles around all day, not just to stave off dehydration but to avoid just about every other ill from dry skin to constipation to fatigue, muscle weakness, and colds.
Are we really that desiccated? Or just deluded?
Obviously, since our bodies are two-thirds water, we need water to survive. Water is the nutrient “you can go without the shortest period of time,” says Dr. George Blackburn, a nutritionist at Beth Isreal Deaconess Medical Center.
True enough, but are most of us really getting too little?
Pop culture says so. Take last September’s Men’s Health magazine, which extolled the wonders of water to achieve miracles like this: “Lose fat – without pesky exercise!”
Then there’s Dr. Fereydoon Batmanghelidj, an Iranian-born physician (now in Virginia) who wrote “Your Body’s Many Cries for Water.” He says people “need to learn they’re not sick, only thirsty,” and that consuming water “cures many diseases like arthritis, angina, migraines, hypertension and asthma.
He says his insights – from reading, not research – are a “paradigm shift” and that he self-published his ideas lest they “be suppressed.”
On the other side, there’s Dr. Gary Curhan, who says that unless you have kidney stones, forcing yourself to drink water when you’re not thirsty is silly.
“There’s no evidence at all that drinking extra water is beneficial for an otherwise healthy person,” says Curhan, a kidney specialist at Brigham and Women’s and Massachusetts General hospitals.
Dr. Ronenn Roubenoff, a Tufts nutritionist, agrees: “A vitamin deficiency can be cured by vitamin treatment, but does taking more supplements than you need make you even better? The answer for water, just like vitamins, is probably no.”
In other words, if you eat regular meals and drink liquids as you eat, you’re probably fine, says physiologist Michael Sawka, chief of thermal and mountain medicine at the US Army Research Institute of Environmental Medicine in Natick.
Where all the experts, self-appointed and otherwise, agree is that actual dehydration can be deadly, not just for elderly folks who may lose a sense of thirst but for healthy, young jocks, too.
Last fall, three wrestlers, among them 21-year-old Jeff Reese of the University of Michigan, died trying to sweat themselves down to fighting weight. Reese died of a heart attack and kidney failure after trying to lose 12 pounds in one day by not eating or drinking and by working out – in a rubber suit – for two hours in a room at 92 degrees Fahrenheit.
Dehydration can cause muscle cramps, and “this person cramped his heart,” says Tufts exercise physiologist Ann McDermott. Body temperature soars, the concentration of minerals called electrolytes in the blood rises (which disrupts the ability of muscles to contract and relax properly), and heart rhythm abnormalities may develop.
But it’s a safe bet that most water guzzlers are less concerned with dehydration than with general health and beauty. So here are the facts – and myths – about water:
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How much do you need? On a sedentary day, to balance water lost through urination, breathing, and sweating, you should consume half an ounce of water for every two pounds of body weight. If you’re 120 pounds, that’s 7 1/2 eight-ounce cups.
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How can you get this much? Easily, and not just by drinking – there’s water in fruits, veggies, and other foods. If you’re still worried, keep water at your desk to sip.
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Do caffeinated beverages count? Sort of. Coffee, tea, and caffeinated sodas are mild diuretics, making you urinate more. But they’re basically water, so they help somewhat.
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What about sweet drinks and fruit juices? They count because they’re mostly water. But the sweetness can make you thirsty – and they’re fattening.
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OK, how about beer (or other alcoholic drinks)? Beer is mostly water, too, but because alcohol is dehydrating, you can’t count beer as hydration. That goes double for wine and liquor, which have so little volume they don’t contain much water.
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Does drinking lots of water make you lose weight faster? Not directly. But filling up on water, plus fiber, can make you feel full, with few calories.
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Does water flush fat cells out of the body? Nope, sorry.
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Does extra water moisturize skin from within? No. All you need for your skin – and other organs – is basic hydration, says Dr. Richard Johnson, a dermatologist at Beth Israel Deaconess.
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Does water fight constipation? Again, it’s basic hydration that keeps things normal. Drinking excess water won’t help. (If you have diarrhea, though, that’s when you do need extra water. Some people make the mistake of trying to stop diarrhea by not drinking.)
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Can water rid you of excess mucus in your nose or throat? Mucus is made from water, so you need to be adequately hydrated to make it. But you can’t make mucus thinner or a cough looser by drinking more, says Kenneth Lema pharmacist at the University of California San Francisco School of Pharmacy.
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Is bottled water better for you than tap water? No.
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What about water needs during exercise? That’s where you should take extra care, says the American College of Sports Medicine. When you exercise hard, especially in the heat, by the time you feel thirsty you’re already dehydrated.
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It’s sensible to drink some water before a long, vigorous workout. During exercise, if you sweat a lot, drink 8 ounces every 20 minutes. Afterwards, drink several glasses, even a quart.
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Do you need to replace electrolytes after a sweaty workout? Not if you eat a normal diet.
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So there’s no need for sports drinks like Gatorade? Probably not for workouts less than an hour. Gatorade and similar drinks can provide energy during longer workouts and can help replace sodium and potassium lost through sweating. But if you do drink them, get those with 8 percent or less carbohydrate. Carbohydrates slow stomach-emptying, which means it takes longer to get water into your system.
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Does drinking water during hard exercise reduce fatigue? It seems to. Physiologist Edmund Burke of the University of Colorado in Colorado Springs studied skiers who either drank water only at lunch or sipped all day from a CamelBak portable water system. The sippers felt stronger and less tired, he says.
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Is it possible to drink too much water? Yes. Too much water dilutes the concentration of sodium in your blood and causes seizures and impaired thinking. But for most of us, it would take 15 quarts a day to cause this.
So what’s the bottom line?
Do take dehydration seriously if you’re elderly or exercising very hard. Beyond that, don’t expect medical miracles from sipping all day. You probably don’t need to force yourself to drink water. You may be dehydrated if:
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You are elderly and fall a lot (especially if you take diuretics, which make you lose water) and take anti-hypertensive drugs.
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Your urine is dark (vitamin supplements and other substances can also this).
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You’re not urinating as often as usual.
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Your mouth is dry.
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You weigh a couple of pounds less one morning than the day before.
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You get a low-grade headache after working out.