We all know that water is a very precious resource. We also know that our bodies need water otherwise we would die.Every cell in the human body depends on water for survival.In fact , all things -plants as well as animals-are made up of water. The human body, for instance , is made up of 65 percent water.
The human body contains a total of about five liters of blood . Of this, about three liters is water. Every day ., adult human being drinks about two liters of water . The body gets another liter through food. Vegetables, eggs and even meats contain water. No matter how thirsty one feels or how much water one drinks, the amount of water in the blood remains the same.
You may think that in such a situation, no human being should ever feel thirsty. But this is exactly what happens when the human body undergoes any kind of exercise . For example, when you run, walk ,play, work or even breathe , you will lose water. Since the amount of water in the body must remain constant, the amount that you lose through exercise must be replaced.This loss of water gets registered in the brain and it sends signals to your mouth and throat. This is when you begin thirsty.