26
sahtak - June 2010
H
ow 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, includ-
ing 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
Water is your body's principal chemical com-
ponent 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 condi-
tion 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 replen-
ish its water supply by consuming beverages and
foods that contain water.
So how much water does the average, healthy
adult living in a temperate climate need? In gen-
eral, doctors recommend 8 or 9 cups. Here are
the most common ways of calculating that
amount:
• Replacement approach.The average urine out-
put for adults is about 1.5 liters (6.3 cups) a day.
You lose close to an additional liter (about 4
cups) of water a day through breathing, sweating
and bowel movements. Food usually accounts for
20 percent of your total fluid intake, so if you
consume 2 liters of water or other beverages a
day (a little more than 8 cups) along with your
normal diet, you will typically replace your lost
fluids.
• Eight 8-ounce glasses of water a day.An-
other approach to water intake is the "8 x 8
rule" — drink eight 8-ounce glasses of
water a day (about 1.9 liters).The
rule could also be stated, "Drink
eight 8-ounce glasses of fluid a day,"
as all fluids count toward the
daily total.Although the
approach really isn't
supported by scientific
evidence, many people
use this easy-to-remember
rule as a guideline for how much
water and other fluids to drink.
• Dietary recommendations.The Institute of Med-
icine advises that men consume roughly 3 liters
(about 13 cups) of total beverages a day and
women consume 2.2 liters (about 9 cups) of total
beverages a day.
Even apart from the above approaches, if you
drink enough fluid so that you rarely feel thirsty
and produce 1.5 liters (6.3 cups) or more of col-
orless or slightly yellow urine a day, your fluid in-
take is probably adequate. If you're concerned
about your fluid intake, check with your doctor
or a registered dietitian. He or she can help you
determine the amount of water that's best for
you.
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 activ-
ity 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 ad-
ditional fluid you need de-
pends on how much you sweat
during exercise, and the duration and
Water is essential to good
health, yet needs vary by
individual. These guide-
lines can help ensure you
drink enough fluids.
Water: How
much should
you drink
every day?
