Water is one of the most important nutrients in your sports diet. Some athletes assume that they only need to drink adequate water for practice or a race. In reality, your goal should be to be well hydrated at all times to maintain your energy level. Water serves several functions in the body: Water in blood transports glucose, oxygen, and fats to working muscles and carries away metabolic by-products such as carbon dioxide and lactic acid. Water in urine eliminates metabolic waste products. The darker the urine, the more concentrated the wastes. Water in sweat dissipates heat through the skin. During exercise water absorbs heat from your muscles, dissipates it through sweat and regulates body temperature. One pound of sweat loss represents about 275 calories of dissipated heat. Water in saliva and gastric secretions helps digest food. Water throughout the body lubricates joints and cushions organs and tissues.
For non-practice or non-race: Rather than count glasses of fluid, drink liquids with each meal and monitor your urine output. If you make trips to the bathroom every 2 - 4 hours, you are probably drinking enough.
For practice and race days: Start drinking fluids early to prevent dehydration. Ideally, you should drink 8 -10 ounces or as much as you can tolerate for every 15 - 20 minutes of strenuous exercise. Always drink before you are thirsty. By the time your brain signals thirst, you may have lost 7% of your body weight, which is equivalent to 1.5 pounds (3 cups or 24 ounces) of sweat for a 105 pound person. A 3% loss (4.5 pounds) can significantly hurt your performance and make the difference between winning and losing.
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