The amount of water a person needs to drink each day varies based on the person’s size and activity level. The Food and Nutrition Board of the Institute of Medicine recommends that the average female consume 2.7 liters of water daily and the average male 3.7 liters.
A person should drink extra water after exercising, during an illness and after prolonged exposure to hot weather. Pregnant women and women who are breast feeding require up to 3 cups more water each day.
The human body depends on water to carry nutrition to cells and to flush out toxins. Lack of water leads to dehydration, which causes fatigue and the eventual shutdown of bodily functions.