Every day you lose water through your breath, sweat, urine and bowel movements. The adequate intake for men is roughly 3 liters (about 13 cups) of total beverages a day. The adequate intake for women is 2.2 liters (about 9 cups) of total beverages a day. At a minimum, drink at least eight 8-ounce glasses of fluid a day.
Nutrition & Dietetics Specialist
The general rule of thumb is to drink (in ounces) half your body weight (in pounds). If you are active, or exercise an additional 8 ounces of fluid for every hour of exercise is recommended for ideal hydration.
The Dietary Reference Intakes from the Institute of Medicine recommend a total daily beverage intake of 13 cups for men and 9 cups for women. This amount is for generally healthy people living in temperate climates. Individual needs vary, so some people can be properly hydrated at somewhat higher or lower levels of water intake. Also, keep in mind that this recommended amount may come from a variety of sources. It includes other beverages—even those containing caffeine—in addition to the water that you drink.
When you're exposed to extreme temperatures—very hot or very cold—your body uses more water to maintain its normal temperature. Under these conditions, you may need to increase your fluid intake.
I recommend a minimum of six 8-ounce glasses a day for most people, but if you're active or live in warm climates, you may need a little more. And don't go overboard: There's no need to gulp down 12 glasses unless, of course, you’re training for a race or hiking the Grand Canyon.
Having trouble hitting the daily six-glasses goal? Make it easier by getting into the habit of drinking a glass with each meal. And you should try to stick with plain old water instead of drinks like iced tea or lemonade. If you’d like to add some flavor, try a squirt of lemon, lime, grapefruit or even tangerine. Other zero-calorie alternatives that can help you reach this goal include herbal iced tea, carbonated water or flavor infused waters.
Most women need eight to nine cups of total fluids a day, including all beverages and the water in foods. Remember that everyone's body needs water. We lose it by sweating, excretion, or simply not taking in enough through foods—like fruits and vegetables—and drinks. Mild dehydration (losing less than 2% of your body weight due to inadequate fluids) can cause health problems, including dizziness and headache.
To keep your body supplied with the fluid it needs, especially when exercising, follow these tips:
- Start with a baseline of eight to nine cups of total fluids a day.
- Increase according to the weather. High temperatures or humidity outside, heated indoor air and high altitudes all cause you to need more fluids.
- Add when exercising. Drink one cup of fluids every 15 minutes during physical activity. Sports drinks are recommended over water when exercising because they contain electrolytes—important to provide the minerals necessary for proper cellular metabolism—which is disrupted during physical exertion. Electrolyte replacement also helps maintain proper muscle contraction and cardiac function.
- Add more for big events. If you're going to be in a race or charity walk, make sure you drink enough to be well hydrated the day before. Also, drink a glass of fluids an hour before the event.
- Drinking for two? Pregnant and nursing women need additional fluids. Talk with your healthcare professional about what's best for you.
Dehydration looks and feels lousy: It saps skin and triggers fatigue. Fill your glass regularly and add a squeeze of lemon or orange if you like. Listen to your thirst signals; you don’t have to check off eight full glasses of pure water a day. This old recommendation was busted earlier this year when two kidney experts had a scientific review published in the Journal of the American Society of Nephrology. In it, they show there’s no clear-cut scientific rationale for the average healthy individual to drink eight glasses of water or more a day. Remember, too, that you get water through a variety of sources like fruits and teas.
From The Mind-Beauty Connection: 9 Days to Less Stress, Gorgeous Skin, and a Whole New You by Amy Wechsler.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.