This title has become my questions too..so I find the answer at MSN health article. It describe that :
The average bottled sports drink has about 150 to 200 calories. New lighter versions, “sports waters,” provide as few as 30 calories per bottle. Sports drinks provide calories in the form of carbohydrates (and sometimes, small amounts of protein.)
You may need a sports drink if you need more energy, but not all exercise situations dictate that you will. Whether a sports drink can help your workout—or if it’s just a slurp of unnecessary calories—all depends on your exercise goals, your energy status leading up to the workout, and the type, length and intensity of your workout.
The average bottled sports drink has about 150 to 200 calories. New lighter versions, “sports waters,” provide as few as 30 calories per bottle. Sports drinks provide calories in the form of carbohydrates (and sometimes, small amounts of protein.)
You may need a sports drink if you need more energy, but not all exercise situations dictate that you will. Whether a sports drink can help your workout—or if it’s just a slurp of unnecessary calories—all depends on your exercise goals, your energy status leading up to the workout, and the type, length and intensity of your workout.
