“Do not underestimate the importance of drinking water,” urges Dr. Bautch. “When playing tennis, you lose a lot more fluids than you realize because a lot of your perspiration simply evaporates.” According to Dr. Bautch, “water is your best choice for hydration. Whatever you do, don’t drink sodas, because they actually take more water from your body to push them out of your system than they put into your body.”

To determine the optimal amount of water to drink in a given day, take your bodyweight and cut it in half. That figure represents the number of ounces of water you should drink. For example, if you weigh 100 pounds, you should try to drink 50 ounces of water per day.