Again and again I see DanceSport athletes, in long, high-energy competitor practice sessions, come and go with merely a few sips of water the entire time. Sports nutritionists tell us that hydration is a key part of athletic performance.

Aside from daily intake of liquids needed to support normal everyday activity, it has been estimated that athletes lose between 300 and 2,400 milliliters (1.5 to 10 cups) of fluids (depending on intensity level) during every hour of physical exertion. This is mainly in the form of sweat, but also includes fluids lost through breathing. Every pound of weight lost during a training session is equivalent to 20 cups of liquid.

Kelly Anne Erdman, M.S., R.D., and 1992 Canadian Cycling Olympian (now a nutritionist in Calgary), recommends that athletes consume 10-15 milliliters of fluid for every kilo of your bodyweight for every hour of activity. As well, she says it’s important to listen to your body for signs of dehydration that will limit your performance.

Water is the ideal beverage for short training sessions, or even during competition where your exertion takes place only for 10 minutes at a time. But for long training sessions lasting 90 minutes or more, it’s not enough to drink water. One of the most important aspects of liquid intake is replacing sodium lost through sweat. Salt contains sodium, so people often mistake sodium for salt, but they are not the same thing. There is no sodium in plain water, but you can use energy drinks formulated especially for athletes to replace sodium and electrolytes lost through training. Plain water will actually reduce your body’s drive to drink more beverages which are vital to your workout! Beverages like Gatorade contain sodium and minerals like potassium to replace electrolytes.

Sodium helps draw water across the lining of your intestines and into your blood stream, providing essential hydration as you exert yourself in sports activities. If your blood sodium levels are low, your fluid absorption rates will decrease, prolonging the effects of dehydration and making it harder for your body to rehydrate. In other words, even if you drink plenty of water, plain water will not replace your sodium levels and you’ll find it harder to stay hydrated. Athlete blood tests are used in some sports to determine sodium levels before, during and after intense exercise.

Different athletes have different rates of sweat loss. Some sweat a great deal during a practice, while others don’t. More importantly, different people have different levels of “saltiness” to their sweat, reflecting sodium loss. The more you sweat, and especially if your perspiration is salty, the more important it is to replace your sodium levels during and after a practice session. Because it’s impractical for endurance athletes (for example, a marathon runner or cyclist pushing their body for hours at a time) to drink enough fluids to replace energy lost in lengthy workouts, they will often ingest salty foods before a race, or take sodium tablets, to supplement the sodium loss that will take place during the event. They will also make sure they take in salty foods at the end of the race to further replace sodium lost.

DanceSport athletes usually don’t need to worry about sodium loss too much, but in long training environments or competition situations where you need to perform multiple rounds over several hours, you will need to consider your sodium levels.