You must stay hydrated, but I'm not sure if drinking water is good advice. You have to not forget your electrolytes. Something like Gatorade works, though.

In moderation. Some people consume more calories than they burn by chugging sports drinks during a workout.

And most people aren't exercising any anywhere near the level that they need something more than water to stay hydrated.

Mind you, it's amusing when you see unhealthy people drinking them thinking that they're better than any other sugary drink.

Vita coco is awesome for this!