We see those sport drink commercials flooding our attention with us believing that we need their product during our sporting activity. They want us to believe that if we drink their product, we will perform better or as good as the pros do because they drink the same product. But do we really? Are these better than water alone?
In a nutshell, the research suggests that if our activity lasts more than an hour, with vigorous activity (such as competitive endurance events, summer conditioning, or in hot environments), yes, a sports drink is better than drinking water alone. The carbohydrates and electrolytes in the sports drink do help replenish those that are lost during your activity.
However, that means for most weight training programs alone, they are not necessary. Your program should not last for more than an hour. Many programs have rest periods that last longer than you are actually active, so your carbohydrate stores are not exhausted enough that would require any need for a sports drink. However, there still are exceptions: the environmental conditions, exercise intensity, acclimatization, aerobic fitness level, hydration status, age and gender can all have an effect on you will perform during your workout.
For those that routinely train intensely for more than an hour, you will have to deal with dehydration. During endurance exercise, the research suggests 150 to 350 mL (6 to 12 oz) of fluid should be consumed every 15 to 20 minutes. There has not been any recommendations established for resistance training and fluid losses alone, however, this same recommendation can also apply. Your rate of fluid loss while exercising will depend on the same conditions listed above (i.e. environmental conditions, intensity of play, etc.).
In order to replenish lost glycogen during your training, bring a water bottle containing a solution of six to seven percent carbohydrate and electrolytes, such as Cytomax, Heed, G Push or Hammer Gel. Try to avoid Gatorade, Powerade or any of the common sport drinks seen on commercials because they contain a considerable amount of table sugar, which may lead to nausea, diarrhea and/or poor replacement of muscle glycogen.