As summer weather heats up, our bodies can quickly become dehydrated. Drinking plenty of fluids -- especially water -- is important.
The human body is about two-thirds water. Dehydration occurs when a person loses more water than he takes in -- by sweating, for example. Playing outdoors, working in the heat or just being in a warmer temperature increases the need for more water.
Water remains the best drink for keeping the body hydrated because it's easiest for people to absorb. Cool water absorbs more readily than warm, hot or ice water.
By the time a person feels thirsty, they have already started to become dehydrated. Thirst occurs when a person has already lost 0.8 percent to 2 percent of his or her body weight.
Water loss that develops slowly can turn on a sense of thirst in time to prevent serious dehydration. Water loss that develops quickly, such as with physical activity, may not be accompanied by a sense of thirst.
Fluid needs of children should be monitored very carefully, especially during warmer months. Children don't tolerate heat as well as adults because their bodies generate more heat relative to their size. They are not as quick to adjust to changes in temperatures. Plus, children have more skin surface relative to their body size which means they lose more water through evaporation from the skin. Kids tend to forget to drink when they are playing and need to be reminded. They usually don't instinctively drink enough fluid to replace what their body loses.
Muscle work of any kind causes the body to lose water through sweat. This is true even when swimming or playing in other cool environments. Water breaks should be taken every 15 minutes during activity. Preferably, children should drink at least half a cup of water during those breaks.
As people get older, they may not be able to rely on thirst to indicate a need for fluids because the ability to sense thirst declines over the years. Or, older adults may just forget to drink enough liquid. It is especially important for older adults to monitor their fluid intake to maintain adequate hydration. Failure to do so can increase risk of urinary tract infections, pneumonia, pressure ulcers, confusion and disorientation. Also, since body water decreases with age, older adults have a smaller margin of safety and are at higher risk for dehydration. Lack of fluids is one of the most frequent reasons people over 65 years of age go to the hospital.
How much fluid you should drink each day is a simple question with no easy answer. Studies have produced varying recommendations over the years. Your need for liquids depends on many factors, including your health, how active you are and where you live.
The Institute of Medicine has determined that an adequate intake for men is roughly 3 liters (about 100 ounces or 13 cups) of fluid a day. The adequate intake for women is 2.2 liters (about 73 ounces or 9 cups) of fluid a day. For many people, 80 percent of this amount is met by consuming water and beverages, while the other 20 percent comes from foods.
When you exercise or engage in any activity that makes you sweat, you need to drink extra liquid to compensate for fluid loss. An extra 1.5 to 2.5 cups of water should be enough for short bouts of exercise. But intense exercise lasting more than an hour requires more fluid intake. Although not a precise indicator, the Hydration Calculator found at www.weather.com/outlook/health/fitness/t... can be helpful when used as a guideline for determining water intake.
So, drink plenty of fluids and have a safe and enjoyable summer.