Years ago (when we seniors were in high school) the philosophy was just the opposite of what it is today: the coaches used to tell players NOT to drink during a sport, “because it would cause cramps”; and in hot weather, they constantly fed them salt pills.
Today, it is generally accepted that tennis players should try to fully hydrate themselves before playing a tough match on a hot day; and that they should drink some on every change-over to try to keep up with the fluid loss.
Years ago, I had a disagreement with my doctor, who insisted urine color had no correlation to your hydration level. Well, he was totally wrong because “normal urine” can range in color from pale yellow to a deep amber; and is directly related to how concentrated the urine is … thus a great measure of the water level in your body.
If you know you are going to be playing in overly hot circumstances, you should start the hydration process the night before; and then reinforce it with a good drink before the match starts. Then, do not wait till you “feel thirsty,” but drink some on every change over. By the time you feel thirsty while exercising, it is too late to catch up on becoming dehydrated. And if you ever STOP SWEATING, stop playing! That is a warning that you are about to suffer severe dehydration.
But be careful of over doing a good thing of drinking. There is also something called Water Intoxication and Hyponatremia, that is caused by drinking too much, which depletes your body of the critical electrolytes of sodium and potassium.
More on drink choices to come.