What
about Water?
According to Mayo
Clinic the following suggestions should be considered:
How much water should you drink each day?
It's a simple question with no easy answers. Studies have produced varying
recommendations over the years, but in truth, your water needs depend on many
factors, including your health, how active you are and where you live. Although no single formula fits everyone, knowing more about your body's need for fluids will help you estimate how much water to drink each day.
Health
benefits of water:
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Water is your body's
principal chemical component and makes up about 60 percent of your body weight.
Every system in your body depends on water. For example, water flushes toxins
out of vital organs, carries nutrients to your cells and provides a moist
environment for ear, nose and throat tissues.
Lack of water can lead to
dehydration, a condition that occurs when you don't have enough water in your
body to carry out normal functions. Even mild dehydration can drain your energy
and make you tired.
How
much water do you need?
Every day you lose water through your
breath, perspiration, urine and bowel movements. For your body to function
properly, you must replenish its water supply by consuming beverages and foods
that contain water.
So how much fluid does the average,
healthy adult living in a temperate climate need? The Institute of Medicine
determined that an adequate intake (AI) for men is roughly 3 liters (about 13
cups) of total beverages a day. The AI for women is 2.2 liters (about 9 cups)
of total beverages a day.
What
about the advice to drink eight glasses a day?
Everyone has heard the advice,
"Drink eight 8-ounce glasses of water a day." That's about 1.9
liters, which isn't that different from the Institute of Medicine
recommendations. Although the "8 by 8" rule isn't supported by hard
evidence, it remains popular because it's easy to remember. Just keep in mind
that the rule should be reframed as: "Drink at least eight 8-ounce glasses
of fluid a day," because all fluids count toward the daily total.
Factors
that influence water needs
You may need to modify your total fluid
intake depending on how active you are, the climate you live in, your health
status, and if you're pregnant or breast-feeding.
- Exercise. If you exercise or engage in any activity that makes you sweat, you need to drink extra water to compensate for the fluid loss. An extra 400 to 600 milliliters (about 1.5 to 2.5 cups) of water should suffice for short bouts of exercise, but intense exercise lasting more than an hour (for example, running a marathon) requires more fluid intake. How much additional fluid you need depends on how much you sweat during exercise, and the duration and type of exercise. During long bouts of intense exercise, it's best to use a sports drink that contains sodium, as this will help replace sodium lost in sweat and reduce the chances of developing hyponatremia, which can be life-threatening. Also, continue to replace fluids after you're finished exercising.
- Environment. Hot or humid weather can make you sweat and requires additional intake of fluid. Heated indoor air also can cause your skin to lose moisture during wintertime. Further, altitudes greater than 8,200 feet (2,500 meters) may trigger increased urination and more rapid breathing, which use up more of your fluid reserves.
- Illnesses or health conditions. When you have fever, vomiting or diarrhea, your body loses additional fluids. In these cases, you should drink more water. In some cases, your doctor may recommend oral rehydration solutions, such as Gatorade, Powerade or CeraLyte. Also, you may need increased fluid intake if you develop certain conditions, including bladder infections or urinary tract stones. On the other hand, some conditions such as heart failure and some types of kidney, liver and adrenal diseases may impair excretion of water and even require that you limit your fluid intake.
- Pregnancy or breast-feeding. Women who are expecting or breast-feeding need additional fluids to stay hydrated. Large amounts of fluid are used especially when nursing. The Institute of Medicine recommends that pregnant women drink 2.3 liters (about 10 cups) of fluids daily and women who breast-feed consume 3.1 liters (about 13 cups) of fluids a day.
Beyond
the tap: Other sources of water
Although it's a great idea to keep
water within reach at all times, you don't need to rely only on what you drink
to meet your fluid needs. What you eat also provides a significant portion of your
fluid needs. On average, food provides about 20 percent of total water intake.
For example, many fruits and vegetables, such as watermelon and tomatoes, are
90 percent or more water by weight.
In addition, beverages such as milk and
juice are composed mostly of water. Even beer, wine and caffeinated beverages —
such as coffee, tea or soda — can contribute, but these should not be a major
portion of your daily total fluid intake. Water is still your best bet because
it's calorie-free, inexpensive and readily available.
Staying
safely hydrated
Generally if you drink enough fluid so
that you rarely feel thirsty and produce 1.5 liters (6.3 cups) or more of
colorless or light yellow urine a day, your fluid intake is probably adequate.
If you're concerned about your fluid intake or have health issues, check with
your doctor or a registered dietitian. He or she can help you determine the
amount of water that's right for you.
To ward off dehydration and make sure
your body has the fluids it needs, make water your beverage of choice. It's
also a good idea to:
- Drink a glass of water or other calorie-free or low-calorie beverage with each meal and between each meal.
- Drink water before, during and after exercise.
Although uncommon, it is possible to
drink too much water. When your kidneys are unable to excrete the excess water,
the electrolyte (mineral) content of the blood is diluted, resulting in low
sodium levels in the blood, a condition called hyponatremia. Endurance
athletes, such as marathon runners, who drink large amounts of water, are at
higher risk of hyponatremia. In general, though, drinking too much water is
rare in healthy adults who eat an average American diet.
