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by Jim Miller MD

January 12, 2009

While all tennis players, runners, soccer players know the importance of hydration; swimmers frequently overlook this critical key to performance. Swimmers do not see the fluid loss, so most do not think about it. Here are some questions to consider that will impact how you approach hydration during a typical pool workout.

• How hydrated are you at the beginning of the training session?
• How many caffeinated drinks did you consume during the day, knowing that caffeine serves as a diuretic and depletes you of total body water? As an aside, did you realize that decaf has caffeine in it also?
• How many hours of training have you had today?
• If you are not training routinely, how acclimated are you to training or are you jumping back into the lane that last saw you weeks (months) ago?
• How warm is the water in which you are training?
• Are you having problems with cramping as the practice goes on and on and on?
• Does it seem like regardless of where you are in your season, your last set is the weakest?
• Are you taking any medication that would affect hydration? An easy example for masters would be the commonly prescribed diuretics, but many supplements and herbals may also have diuretic effects, which need to be considered.
• Do you have a medical problem that would affect your hydration status? Here a great example is diabetes as well as many of the metabolic diseases, which affect the ability of kidneys to respond to hydration requirements.

All of these questions may point to dehydration as a key factor that will affect the success of your training and performance.

So, how much should you drink during a typical practice? Typically, an athlete may loose between 1-3 pounds of water per 1-hour training session, unless you have to compensate for one of the questions already posed. If any of these questions suggest that you are already in trouble, you may be lower than even 2-4 pounds already!

One to two large water bottles will help to keep your muscles maximize their performance. Start the first sips during warm-up and do not wait until you are thirsty. That is too late. You know that you have been successful if you need to urinate following practice and that urine is clear in color.

Finally, use only your own water bottle that you bring for your own use. Wash it out every day at home. Leave it open and let it dry out between sessions.

Remember, it is all in the water!

Jim Miller, MD
Family Practice and Sports Medicine
National Team Physician, USA Swimming