Water and Staying Hydrated

by Carmen Roberts, M.S., R.D., L.D.N. Health Professional, Medical Reviewer

With the summer heat comes an increased need for fluids. We've all heard about the importance of drinking at least eight glasses of water each day.

But why?

How water helps our bodies

Water is crucial to many of our body's functions. Our body loses water each time we exhale, sweat, and use the bathroom. Without enough water, our bodies become dehydrated. We need to replace this lost fluid each day with an adequate amount of water to maintain these bodily functions.

The Institute of Medicine recommends a total water intake of 16 cups each day for men and 11 cups a day for women. While some of this fluid comes from the foods we eat, most needs to come from drinking water. A general guideline is to drink half of your body weight in fluid ounces. So if you weigh 160 pounds, you need a minimum of 80 ounces (or 10 eight-ounce glasses) of water each day. Not surprisingly, the average person does not meet their daily fluid needs.

A good rule of thumb to determine if you are getting enough water is the color of your urine. If it is clear or straw-colored, you probably are getting enough water. If your urine is dark, it is a sign that you probably are dehydrated. Don't wait until you are thirsty to drink water this is typically a sign that you already are dehydrated. To ensure that you are getting enough water throughout the day, carry a water bottle around with you wherever you go (in the car, at your desk at work, etc.). Sipping on water throughout the day is the easiest way to get enough fluid. Don't consume all of your water at once you will likely feel too full to drink all that you need.

What about hydration drinks?

Water is sufficient for most people to replace fluid lost during exercise. But for people who are exercising 60 minutes or more, a hydration drink (which contains sodium and potassium, electrolytes that are lost through sweat) may be appropriate.

Some athletes use juice and even milk to replace the energy that is lost during a workout and to replete the energy stores in their muscles. But be mindful that many of these drinks are packed with added sugars.

Proper hydration is critical for athletic performance, particularly when you are exercising in the heat or for long periods of time. When your body is dehydrated, you may experience muscle cramps and fatigue. Without adequate water, your body can't sweat to cool itself down. This can ultimately lead to heat stroke. When you are exercising outside in the summer, you will need even more water to stay hydrated. For each pound of fluid lost after exercise, you need two to three cups of water to replace that lost fluid.

Water and weight lossResearch has shown that drinking water before meals can make you feel fuller more quickly, thereby reducing the amount of calories consumed. And when your body is well-hydrated, your muscles and organs work more efficiently. This can actually boost your metabolism, assisting with weight loss. Making sure you are getting enough water each day is one of the easiest steps you can take to start losing weight.

Other considerations

There are other situations that require increased fluid needs. During pregnancy extra fluid is needed to help maintain the mother's increased blood volume. Once the baby is born, sufficient water intake is necessary for breast milk production. Your physician may also advise you to increase your fluid intake if you have a bladder infection or kidney stones or if you've experienced an illness that has caused a prolonged fever, vomiting or diarrhea.

Carmen Roberts, M.S., R.D., L.D.N.
Meet Our Writer
Carmen Roberts, M.S., R.D., L.D.N.

Carmen is a Registered Dietitian. In addition to writing for HealthCentral, she has spent her career working at Johns Hopkins and is also an adjunct faculty instructor for Excelsior College. Carmen has over 20 years of experience in nutritional counseling, education, writing, and program management and is a certified specialist in adult weight management. She enjoys educating her students and clients about how nutrition affects the body and its role in overall health and wellness.