Beat The Heat -- Stay Hydrated!

Julie Redfern, L.D., R.D.N., and Michelle McAndrews
Brigham and Women's Hospital
Previously published on Intelihealth.com, May 20, 2005
Reviewed October 2009
Click here for a printable format.

• Water Versus Alternative Beverages
• How Much Fluid Is Enough?
• Tips for Keeping Hydrated

Hot weather will be here soon. Along with trying to stay cool, you need to be sure you drink enough
fluids. People often blame the heat when they start to get headaches, light-headedness and
fatigue. These are often the first signs of dehydration, even if you are not thirsty.

The warm weather encourages people to be outside - working, exercising or just enjoying the sun.
All of these activities speed up the loss of body water, with dehydration close behind. Even minimal
dehydration (2% to 3%) can negatively impact your physical and mental performance.

Don't wait for the dry mouth, flushed skin, headaches, lightheadedness or fatigue. You should prevent
dehydration by drinking fluids throughout the day.

A good way to know if you are not drinking enough is to stay aware of the volume and color of your urine.
If you notice a decrease in volume or the color is darker, it's a good bet you're dehydrated.

Many factors can make you dehydrate more quickly than expected. Medications and supplements that
promote increase in urination (diuretics) hasten dehydration. Huge amounts of water move out of the
body through the skin with sweating, and from the lungs during exercise or illness with fever. Women
who are pregnant and lactating require more fluids.

If replenishing lost body fluids is essential to preventing dehydration, does it matter what type of
fluid we consume?

Water Versus Alternative Beverages

Fluids are considered to be any food or beverage that's liquid at room temperature, such as water, ice,
soup, beverages, ice cream, sherbets, popsicles and gelatin. Water is the best fluid for hydration; it
has no calories, sugar, salt, carbonation, coloring or preservatives. No other drink can even come
close to that claim! And water is cheap, despite the huge commercial bonanza that bottled water
has become.

Water is an essential nutrient for life. Our bodies are made up of more than 70% water. Water is
necessary for so many of our basic functions, such as regulating body temperature, removing
wastes, moisturizing our skin, lubricating our joints, and carrying oxygen to our cells.

Water is indeed everywhere. Water is a component of most foods we eat, especially fruits and
vegetables. For example, 1 cup of fruit contains 1/2 cup fluid. However, many people don't drink
water as their main choice of beverage. In addition to bottled water, there's a wide variety of other
beverages marketed to us every day, such as:

Hundred-percent fruit juice contains some vitamins, minerals, and a lot of sugar. In fact, a
16-ounce glass of fruit juice contains about 220 calories and 25 grams of sugar. Fructose, or
fruit sugar, reduces the rate at which we absorb fluid and can actually make you thirstier,
leading to over consumption of calories from juice.

Sports drinks often contain fructose or sucrose syrups, flavorings, salt, citric acid, sodium,
potassium and colorings. The electrolytes, sodium and potassium, are helpful for endurance-
type exercise or activity, but not necessary for everyday exercise. Sports drinks don't hydrate you
any better than water, but, the calories are less than in juices or soda. There are roughly 30
grams of sugar and 100 calories in 16 ounces of sports drink.

Fitness waters are waters sprinkled with an assortment of nutrients, sometimes herbs,
flavorings and sweeteners. These enhanced waters don't usually contain enough vitamins or
minerals to make an impact on your health, and they can be costly. Additionally, there is no
current credible scientific evidence that added herbs affect energy levels or improve health.
These beverages can still count toward your fluid goals, but contain 10 to 100 or more
calories for 16 ounces.

Carbonated beverages such as regular or diet sodas can be high in sugar or artificial sweeteners, and
caffeine. Colas are also high in phosphates that bind with calcium and weaken bones. Regular soda
can contain up to 200 or more calories for 16 ounces.

Coffee, tea and lattes are also very popular. They often contain added sugars and fats along with the
caffeine, and can add up to as many as 450 calories for 16 ounces. Current studies show that
caffeinated beverages may not be dehydrating, as once thought. Limited amounts can count toward
your overall hydration goal. However, since most caffeinated products provide very few nutrients, it is
typically advised to keep intake low.

Flavored waters are beverages with a touch of flavoring with the bonus of zero calories. These
beverages are great for people who prefer flavor in their beverage but wish not to have added calories.

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How Much Fluid Is Enough?

Everyone's hydration needs vary, so the standard prescription of eight, 8-ounce glasses per day of fluid
may not be enough for you. Rather than count cups of fluid, it's more important to be in sync with your
sensation of thirst and to be aware of the early signs of dehydration! During exercise and illness, your
fluid needs are likely to increase dramatically.

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Tips for Keeping Hydrated

• Have a glass of water when you first get up.
• Keep a glass of water next to the bed.
• Enjoy an herbal tea in the afternoon or evening.
• Carry water with you if away from home for long periods.
• Drink before you get thirsty.
• Limit sugary, caffeinated beverages.
• Choose drinks with 10 or fewer calories.
• Know the signs of dehydration.
• The best choice for fluid is WATER!