Dehydration is a concern of every athlete. When the fluid blance of your body starts to fall below normal, your sports performance will suffer dramatically. For decades, athletes in training and competition have been warned to stay away from caffeine, or at least to limit its intake, because caffeine causes dehydration.
This turns out to be a myth. Especially in sports, study after study has proven that caffeine does not alter the fluid balance of the organs in the body, the electrolyte levels, the rate of perspiration, or the core temperature, and it does not increase the likelihood of or contribute to dehydraton. This is an old wives’ tale, pure and simple. It may have arisen because drinking a couple of cups of hot liquid naturally tends to occasion the need to urinate.
So, just remember: Caffeine does not alter overall hydration levels or fluid balance within organs in the body. Period.