Reevaluating daily water intake needs


I've heard different things about how much water to drink. Some people say to drink water before you work out, while others say make certain not to drink too much. What's the latest?

For most of us, knowing how much to drink is fairly straightforward: Do what feels right. But for marathoners and ultra-athletes, or even novices trying their hand at longer events, hydration can be as serious as life and death. So let's break it down by the type of athletics.

Recreational athletes

The rule-of-thumb is to drink at least six to eight, 8-ounce glasses of water daily. Nutrition experts say that if you start to feel thirsty, you have probably already become 1 percent to 2 percent dehydrated. So start trying to replace fluids.

Cedric X. Bryant, chief exercise physiologist at the American Council on Exercise, says to use common sense. He advises you to drink until you aren't thirsty before a workout, but make sure you aren't bloated. His top choice: water.

Kids are a different story. Studies show children are more likely to drink when given flavored sports drinks. So Bryant advises parents to give children the drinks. Even though they contain sugar, they are better for youngsters than becoming dehydrated, he says.

During football and lacrosse seasons, I keep a case of sport drinks in the minivan, in case one of my children - or someone else's - forgets a water bottle.

Competitive athletes

Serious athletes are a different matter.

In recent years, several organizations, including the International Marathon Medical Directors Association, have changed their guidelines on fluid consumption, in part because of a spate of deaths from hyponatremia, or excessive fluid consumption.

The group suggests marathoners consume between 13 and 27 ounces of fluid per hour, according to Runner's World magazine, but not more than 27 ounces.

In the February 15 edition (run, marathon runner Amby Burfoot, who won the Boston Marathon in 1968, sets forth the magazine's new fluid-consumption guidelines.

"The old formula - everyone needs eight glasses of water a day - is out," Burfoot writes. "It has been replaced by formulas based primarily on gender and body weight."

Women, listen up. Burfoot reports that women die most frequently from hyponatremia, in part because their bodies need about 30 percent less water than men. Excess fluid throws off a body's sodium balance, which can cause death in extreme cases.

For men, multiply body weight by .35 to find the number of fluid ounces needed daily, the magazine says. A 180-pound man, for example, needs 63 ounces of liquid daily to stay properly hydrated. Use IMMDA guidelines to adjust fluid intake during marathons or long runs.

For women, multiply weight by .31. A 120-pound woman needs about 37 ounces of fluid daily for proper hydration. Again, adjust intake for marathons and long runs using the IMMDA guidelines.

Doctors and fitness gurus long have studied problems with dehydration. They are beginning to warn that over-hydration can be just as dangerous.

Next week, I'll answer questions about lower back pain.

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