So, when fluid levels in the body are low, physical performance suffers. By the time you feel thirsty, you may have already lost essential fluids and electrolytes that can affect your performance. So, before you begin, drink 4 to 8 ounces of fluid. Drink at least 4 ounces of water for every 20 minutes of activity. For each pound you lose, replenish your body with two cups of fluid.
Water is the best fluid for most activities.
Unless you are a high performance athlete in intensive training, you probably don't need any of the more expensive sports drinks. F orget carbonated sodas. Fluids that are high in sugar are not absorbed as well and can cause stomach aches. If you wonder if you really are getting dehydrated, pinch yourself. Put your hand in front of you and pinch the skin on the back of your knuckles.