Your typical sports drink is a blend of carbohydrates and electrolytes. Most -- if not all -- of the carbs in sports drinks come from sugar, and the electrolytes are generally a mix of salt and potassium designed to replenish what you lose in sweat during an intense workout. Sports drinks also have added flavors and artificial colors to make them more appealing to consumers, which is how you end up with varieties like Cool Blue and Glacier Freeze.
The formulas for sports drinks can vary quite a bit from bottle to bottle. For a regular sports drink, like Gatorade or Powerade, you're usually getting around 14 to 17 grams of carbs and between 110 and 165 milligrams of sodium in an 8-ounce (226 gram) serving [source: Fitzgerald]. An 8 ounce serving of Gatorade has 50 calories, and you're usually getting 16-32 ounces in a bottle, depending on what size you buy [source: Good Morning America]. That means that polishing off a large bottle of Gatorade on the treadmill can add as much as 200 calories to your daily total, which could be more than you burn in that 30-minute session!
So, that sports drink can negate your entire workout. In fact, if you're exercising for less than 45 minutes, chances are you don't need a sports drink at all, because you're not burning enough calories or losing enough electrolytes to require that kind of hard-core replacement strategy [source: Blake]. Just drinking water should do the trick unless it's insanely hot and you're sweating buckets.
Consumers sometimes confuse sports drinks with energy drinks, since both products are marketed as a source of drinkable energy. The difference between the two is all about the ingredients. While sports drinks are designed to replace the nutrients you lose through sweat in a workout, energy drinks rely on stimulants like caffeine and taurine to give you an artificial energy boost. Those stimulants can actually make energy drinks dangerous during a workout, because they elevate your heart rate [source: Mayo].
Some sports drinks even have uses beyond the gym or the field. If you're traveling to a Third-World country where diarrhea-related diseases are a problem, sports drinks can be your best friend. Just like with heavy workouts, diarrhea makes you lose fluids, salt, potassium and carbohydrates, and sports drinks can help replace those lost nutrients [source: PennState Hershey].