A: If you wait until you are thirsty to drink, you have waited too long. During intense exercise the body's thirst mechanism lags behind actual need. It is important to make a conscious effort to drink water before you ever get thirsty.

Your actual requirement will vary depending on the temperature and humidity, the intensity of your workout or event, and how well you acclimated you are. The most reliable indicator of how much water you need is your weight. In hot and humid weather, athletes can sweat off six pounds per hour. Each pound of weight lost as sweat is equal to two cups of water. You can not lose that much fat in a short period of time. Therefore, it is important to weigh yourself nude, or in minimal clothing before and after exercising. For each pound lost, drink two cups of fluid before exercising again. If you routinely lose more than two percent of your body weight, drink more water immediately before and during your workouts or events. All athletes should drink water before, during and after workouts and events.

Q: Is it true that athletes should drink lots of water and juice when they are flying? Why?

A: Yes, this is very important. The air in the plane's passenger compartment is very dry so your body can lose a lot of fluid from evaporation during the flight. For this reason, you should drink plenty of water and juice before, during and after air travel.

The longer the flight, the more water you should drink. This is especially important during overseas flights. Avoid alcohol and caffeine-containing beverages, such as coffee and soda, because they increase your water loss.

Q: What about using sports drinks for fluid replacement?

A: For workouts or events lasting less than two hours, water is excellent for fluid replacement. Athletes sometimes choose sports drinks because they like the taste and feel it makes them drink more fluid. If an event lasts longer than two hours, an athlete may benefit from carbohydrate and electrolytes provided by fluid-replacements type drinks. The drinks should be between 4-8 percent carbohydrate (15-18 grams per 8 ounces of fluid). Drinks with higher carbohydrate can delay the absorption of water, possibly causing cramps, nausea and diarrhea. Be sure to experiment with these drinks during practice instead of trying them for the first time in competition.

Q: Do athletes have to worry about getting enough sodium, potassium and other electrolytes that are lost in sweat?

A: Replacement of these electrolytes is important because they are involved in fluid balance, nerve conduction and muscle contraction. However, you need not worry about replacement until after exercise is over. The one exception is during ultra-endurance events such as 50 mile runs, 100 bicycle rides and triathlons.

Sweat contains small amounts of the electrolytes and is actually less concentrated with electrolytes than your other body fluids. When you sweat, your body loses a lot more water than electrolytes. During exercise, water replacement is the main concern. After exercise, electrolyte replacement is easily achieved by a normal diet. Getting enough sodium is not a problem for most athletes. At most, it only takes a few extra shakes from the salt shaker. Potassium replacement is equally important. Bananas and citrus fruit, as well as juices such as orange and grapefruit are excellent sources of potassium, as are potatoes, tomatoes, meat and milk.