Water is one of our most basic needs. Fifty to sixty per cent of our weight is water. A loss of 20 per cent of the total body water can lead to death. This is why the body needs to replenish its liquid supply.
Thirst is a sensation caused by the body's need for water. The organs and tissues in the body need certain amount of water and salts to function properly.
Too much or too little water or salt can damage or destroy cells. Therefore, we need to regulate and control our water intake.
Thirst is often described as a feeling in the throat. Lack of sufficient saliva can produce this kind of thirst, even when the internal environment of the body does not need more water.
Similarly, the thirst sensation created by the internal environment's needs will disappear briefly if water is drunk to wet the throat. But unless the water reaches the internal environment, thirst will recur after a short time.
• The human brain is more watery than blood — it is four-fifths water.
Credit: My book of questions and answers.