Feeling thirsty? Summer heat accelerates dehydration

Summer is a good time to think about whether or not you're getting enough water.

People spending more time outdoors in 90-plus degree temperatures can easily become dehydrated.

Many people have heard they should get about eight glasses of water per day. But the eight-cup rule isn't exact: A glass could be a big glass or a small one and deliver much different amounts.

To be more precise, the Institute of Medicine says men should get about 125 ounces, or about 16 cups of water daily, and women should drink 91 ounces, or about 11 cups. Those recommendations include water from all foods and beverages—people get about 20 percent of their fluids from food.

People also need more water in hot climates, with increased physical activity and if they have a fever, diarrhea or vomiting.

Dehydration can happen quicker, though, in hot and humid weather, sometimes in half an hour.

People need to be careful about the time of day they exercise outdoors—the early morning or at twilight are more pleasant temperatures for exercise.

If you're outdoors in humid conditions, take longer breaks, and shorten the length and intensity of workouts.

Also, take a water break about every 20 minutes.

While some drinks can help you stay hydrated, others can be detrimental.

Alcohol is the most dehydrating beverage. Caffeinated drinks like coffee or sodas can hydrate, but they also cause you to urinate more, so you lose some fluid.

Water is always the best choice because it comes with zero calories.

Some people have a higher risk of dehydration, too. Kids need plenty of fluids because they can get dehydrated faster than adults. Older people and seniors might also need more fluids because of health conditions.

Pregnant women need to be more careful, too. They need more fluid than when they were not pregnant.

Drinking more water is a good way to stay hydrated, and some studies show it could help people lose weight.

People who drink more water tend to eat and drink fewer calories. For example, substitute a 20 ounce sugar sweetened beverage with water and you'll save 240 calories.

The water fills you up, even if for short periods of time, so you feel less hungry.

The summer is a good time to make a habit out of drinking plenty of pure, plain water. It's free and has no calories.