Do I need sports drinks?
When you're sweating your way to a serious thirst, water isn't always enough. That's why old-time American ranchers used to drink batches of switchel -- a mixture of water, molasses, and vinegar -- during haying season. Workouts have changed since then, and, thankfully, so have the energy drinks. The water is still there, but the molasses and vinegar have been replaced with some form of sugar, minerals such as potassium and sodium, and the ever-mysterious "natural flavors." The end result is basically the same: a double shot of water and muscle food when you need it most.
There's no doubt that sports drinks can help you get through a long, hard workout. (If you're exercising for less than one hour straight, plain water works as well as anything else.) Despite all the talk in commercials about "electrolyte balance," the real value of these beverages lies in the carbohydrates: Sugars and other energy compounds help feed the muscles and delay fatigue. But according to a report in the journal Sports Medicine, added sodium and potassium won't do you much good unless you're sweating profusely for more than four hours (think triathlon).
One consideration for some people is the caloric content of these drinks. If you're trying to lose weight, a 70-calorie quaff means you have to cut back somewhere in your day's diet. If you do this by limiting yourself to one small serving of meat at dinner, great. But if you know you compensate by shunning the fruit bowl, think again about what your body needs most.
How should I use sports drinks?
Try taking a few gulps in the early stages of your workout. The goal is to prevent dehydration, not to cure it. Begin with 8 ounces 20 minutes before you start exercising, then drink four to six ounces (half the amount of liquid in a can of soda) every 15 to 20 minutes; that should be enough for most types of exercise.