While expending energy during exercise, our bodies need more water to continue to function. Heat is removed by sweating to avoid the dangers of having increased body temperature. During intense activity, the body can lose up to two liters of water as sweat. A marathon runner can lose around 13 lbs. of body weight during a race. Dehydration can result due to lack of water intake while exercising.
Dehydration has a significant effect on the body's performance.
The body's energy production needs water to function effectively. When there is not enough water in the muscles, blood volume is decreased so the heart must pump harder to supply the same amount of energy. Recommendations Drink 8-10 8oz. By the time you are thirsty, your body is already dehydrated.