Three Easy Ways to Check for Dehydration

By Jill Castle, MS, RDN

Staying hydrated is a constant effort for many swimmers, requiring a hydration plan around exercise and vigilance for signs of dehydration. In young athletes, a 1% dehydration can impair athletic performance (a one-pound weight loss in a 100# athlete).

A plan for drinking enough fluids throughout the day is the best defense against dehydration. For a recap on how much to drink and when, see this article.

What if you could monitor and correct your own hydration? Ultimately, that is the goal for a self-sufficient athlete—to know your body well enough to make adjustments when things are off.

Here are three easy ways to check your hydration status:

Thirst: “If you feel thirsty, you’re already dehydrated.” While the mechanism of thirst is complicated, it can be associated with the level of dehydration. Using a scale of one to nine, with one being not thirsty at all to a nine being very, very thirsty, researchers have found that young athletes falling between a three and five likely had a 1 to 2 % dehydration.

However, thirst may not always work for young athletes as a signal to drink. More recent research has shown that young athletes may not recognize thirst, or they may deny it, being distracted by other events. For this reason, it is important for parents and coaches to remind young swimmers to drink fluids.

Urine Color: Urine color charts have been developed to help young athletes know when they are dehydrated. Ideally, swimmers want their urine color to be a pale yellow (like fresh-squeezed lemonade or lemon juice), indicating adequate hydration. A strong yellow, orangey-yellow, or brownish green color (read: Mellow Yellow or Mountain Dew) means the athlete is dehydrated and drinking needs to begin pronto!

Researchers have used urine color charts in locker rooms to educate about hydration, and have found them to be effective reminders to drink fluids.

Weight: A pre- and post-exercise body weight is another method for identifying dehydration after exercise (no, the weight lost is not fat—it is water). For every pound lost, 500 milliliters (1/2 liter or 16 ounces) of fluid should be consumed to replenish your hydration state. For example, if you weigh 110 pounds before practice, and 108 pounds after practice, you have lost 2 pounds of water weight, and need to drink 32 ounces of fluid.

However, if you are following your drinking plan and drinking throughout exercise, you’re water weight loss will be less, and so will the amount needed to replenish your hydration status after practice. The goal is to maintain a stable weight after swimming, or to lose very little. This can be accomplished by drinking enough during exercise.

These three simple methods for checking hydration status can help the young swimmer stay hydrated and promote optimal performance in the pool, whether training or competing.