Cool Clear Water
© Natural Health/Weider Publications. All rights reserved.
By Ben Kallen
Lisa Ryan doesn't take a bottle of water when she leaves for work in the morning — she carries a whole trunkful. She drinks before, during and after her morning workout, and has a bottle at the ready anytime during the day. "If I'm dehydrated, I get really tired," says Ryan, a San Diego advertising account executive. "But when I drink water regularly, I have more energy."
It's true: Water enables the loading and storage of energy-giving glycogen in your muscles. It also regulates your body temperature; aids in digestion, circulation and joint lubrication; maintains blood volume; flushes toxins from the liver and kidneys; and helps decrease the risk of numerous cancers by 50 percent or more. Without it, you wouldn't last more than a few days.
Like Ryan, millions of health-minded people are aware of the importance of staying hydrated. American drinks only about five glasses of water per day, according to a survey conducted by Cornell University, instead of the eight glasses that most experts recommend. But is that even the correct amount?
Why Water?
So, five glasses, eight glasses ... does it really matter? It does if you want your body and brain to function properly, says Stella L. Volpe, Ph.D., R.D., associate professor of nursing and the Miriam Stirl Term Endowed Chair in nutrition at the University of Pennsylvania.
Mild dehydration can slow your metabolism by as much as 3 percent, and lead to fatigue and cloudy thinking. "People who are mildly dehydrated might notice a decrease in their physical performance or have muscle cramps, and they might have decreased cognitive function" Volpe says. Since these symptoms can be mild, people suffering from them may not realize they aren't at their best.
A lack of adequate fluids stresses the heart and raises core body temperature quickly, especially during exercise or in hot climates. That's what leads to more serious conditions like heat prostration or heatstroke.
The Right Amount
So how much H2O should you get each day? The answer is, shall we say, fluid.
The "eight 8-ounce glasses a day" is a generalization that continues to be taken literally, says Heinz Valtin, M.D., a retired Dartmouth Medical School physiology professor and author of two widely used textbooks on water balance and the kidneys. "I was asked to find a scientific basis for that recommendation, and I couldn't," he notes.
Thus, one 64-ounce size doesn't fit all. The average man needs more than the average woman, as do athletes of both genders. But it's rarely necessary to break out the measuring cups, emphasizes Valtin. "Drink what you would drink customarily at and between meals, plus more when you're thirsty" he advises.
In other words, your morning coffee, the smoothie with lunch and the soft drink with dinner all go toward fulfilling your water needs and drinking whenever you feel the urge will fill in the gaps.
The meals themselves will also provide fluids. A recent report by the Institute of Medicine of the National Academies extensively reviewed hydration and electrolyte intake and determined that water in food should count toward hydration, as should sports drinks, caffeinated and even alcoholic beverages, The report, in which Volpe participated, provides slightly more regimented rules than Valtin does. It recommends 2.7 liters (91 ounces) of fluid per day for women and 3.7 liters (125 ounces) for men. Of that, 81 percent will probably come from beverages, and 19 percent from food.
"Liquid drinks are 90 to 95 percent water; says Valtin. "Fruits and vegetables are mostly water. Even a piece of white bread is about 30 percent water."
Pangs of Thirst
Hungry? Try a glass of water first, since many people mistake their thirst for hunger. Water even eliminated late-night hunger pangs for most dieters, according to a study at the University of Washington.
Otherwise, thirst is a perfect indicator of a need to drink, Valtin says, a conclusion supported by a recent study in the American Journal of Physiology. Still, many experts believe that if you're thirsty, you're already slightly dehydrated, especially if you're physically active. The American College of Sports Medicine recommends consuming 500 milliliters (about 17 ounces) in the two hours preceding a workout, plus another 5 to 10 ounces every 15 minutes during exercise and in the first hour after.
One way to tell if you aren't drinking enough is to weigh yourself before and after a long workout; if you weigh less, you're dehydrated. (If you weigh more, you may be drinking too much. Normally, your body excretes what it doesn't need, but in extreme cases involving triathletes or marathon runners, too much water can lead to a dangerous shortage of salt, a condition called water intoxication or hyponatremia.)
Another way to balance your intake, Volpe says, is to look at your urine: "It should be a pale yellow. If it's clear yellow, you might be overhydrating. If it's a dark yellow, you may not be drinking enough." She adds that changes in urine color also can result from taking vitamins or other supplements.
Your body is very efficient at regulating its water levels, says Valtin: "The moment you drink a little more than usual, that system goes into effect and you pee more. The moment you don't drink enough, you retain more in your body."
For her part, Lisa Ryan is more than happy to retain her water regimen. "When I don't drink enough, I feel listless, and my skin and eyes feel dry," she says. "But when I listen to what my body needs, I always end up feeling better."
© Natural Health/Weider Publications. All rights reserved.
