Liquid Assets

You may think you drink enough, but chances are you don't. Get the scoop on fluids: how much and how often

By Anne Stein

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Issue date: July/August 2001

Athletes can cramp up if they fail to take in fluids.  Lori Ademski-Peek

Working up a good sweat is a truly satisfying experience ... unless, you do nothing to restock the water or minerals (electrolytes) you lose in the process. Instead of going back for more, you'll be tired, cranky and sore.

Twenty years ago, you didn't need rocket science to stay hydrated, but today things have changed. That's why soccer superstar Mia Hamm and WNBA star Chamique Holdsclaw recently underwent sweat tests at the Gatorade Sports Science Institute near Chicago. Pedaling stationary bikes in an 82°, glass-enclosed room, Hamm wore patches on her head, chest, back, arm and thigh; Holdsclaw had a plastic bag around her arm and hand. The purpose: to determine how much sodium and other electrolytes they lost in sweat.

Both Hamm and Holdsclaw are in top shape, but Hamm found she lost relatively normal amounts while Holdsclaw released comparatively high levels. That, Holdsclaw says, could explain why she occasionally cramps up during games. Now she knows to be vigilant about replacing both fluids and salt when she works out. "I get so focused during a game that sometimes I don't always drink enough," she says.

So how can the rest of us check for high sodium loss without access to a research lab? Examine your skin or clothes after exercising: If you notice a white, salty residue, you need to replace both fluids and electrolytes.

Don't dehydrate

If the idea of carrying a water bottle around and swigging from it constantly turns you off, consider this out about hydration and you may change your mind. No matter what sport or activity you do or how well you do it, you'll enjoy it more if you drink enough. Skimp on fluids and you set yourself up for a variety of unpleasantries -- poor performance, cramps, dizziness, fatigue, headaches, and, in extreme cases, central nervous system damage.

If the weather is warm or humid, you're even more susceptible to dehydration, but you're never completely free of the risk. "There is no sport where fluid isn't important," says Monique Ryan, author of The Complete Guide to Sports Nutrition (VeloPress, 2000). "Even swimmers can get dehydrated."

Glisten carefully

Your body, like your car, stalls when it overheats, so it sweats to keep cool. When you perspire you lose fluid (from blood and cells) and electrolytes -- mainly sodium, which promotes fluid retention and helps prevent cramping. Calcium, chloride, magnesium and potassium are lost in smaller amounts. Everyone releases different levels of sodium, regardless of fitness level. Even if you're not dripping with sweat, you probably need to drink more. The majority of athletes consume about only half the fluid they need while working out, according to several studies. To determine how much water you lose (and therefore need to replace) in a given workout, weigh yourself before and after exercise. If you lose 1% of your body weight (roughly 20 ounces, or 1.25 pounds, for a 125-pound athlete), you're going to feel thirsty and tired. Lose 2% and you might suffer from a headache and chills. If you lose up to 3% or 4%, the signs of dehydration become scarier: chills, cramps, dizziness and nausea.

Another quick method to determine whether you're drinking enough is the urine test. Take a peek at your urine the next time you pee. If it's dark and scant, you probably need to drink more. A pale yellow glow? Your body is closer to being in fluid balance.

Swig sensibly

What's the best fluid to drink? Hint: it's not coffee or Coke. Plain water will probably do if your workout is an hour or less. If conditions are intense or the activity or game runs long, guzzle a sports drink, which will replenish fluids and electrolytes and help refuel depleted muscles.

A beverage rich in carbohydrates isn't necessarily better. "The higher the concentration of carbohydrates, the slower the drink leaves the stomach, so it isn't absorbed as quickly," says Julie Burns, a sports nutritionist in Western Springs, Ill. In general stick to drinks that have about 14 to 17 grams of carbs per eight ounces, says Burns. Stay away from drinks with caffeine (the aforementioned coffee and cola); they speed up water loss, impairing your body's ability to cool itself down.

No matter what you drink, though, staying hydrated should be a core component of your game (and life). "Athletes are always looking for the slightest edge," says Hamm. "There's been so much research in terms of training, but hydration is really a key part of performance."

For more Sports Illustrated Women, check out our latest issue -- on newsstands now. For your FREE preview issue of SI Women click here or call 800-950-5150.