Average adult human body contains 57 to 60 per cent of water. In infant, the percentage is a little higher, approximately 75 to 78 per cent. Our body uses water in all its cells, organs and tissues to maintain body temperature and other bodily functions. It is important to keep our body rehydrated as we tend to lose water while breathing, sweating and digestion. A person can survive without food for about a month but not more than a week without water. One per cent reduction of our body fluid makes us feel thirsty and if it reduces by 10 per cent, believe it or not, we will die