Depending on how long you workout and exactly what kind of exercise you're doing, your body needs different things from you. Hydration is important across the board, but when it comes to drinking fluids there's a big difference between water and sports drinks. Do you need the calories and electrolytes? What about protein? Is plain water better in some situations?

Experts say that if you're exercising for an hour or less at one time all you really need is water. Only when your body is subjected to long endurance-type activities for more than an hour is it in need of a calorie boost and electrolyte replacement. If you're drinking calories during or after a shorter workout you're really just canceling out all the energy you just burned!