According to the Centers for Disease Control and Prevention, every cell, organ and tissue in the human body contains water, which makes drinking it essential to maintaining health on a daily basis. Drinking several glasses of water per day helps the body to replace water that is lost from elimination and sweating.
According to Web MD, it is not necessary to drink eight glasses of water a day. That well-known recommendation was not based on science. However, for the average person water equals life. Therefore, it is wise to drink water anytime a person feels dehydrated. Since the body is 60% water, it is vital to replace fluids that are lost due to normal activity. Replacing fluids is even more important for people that perform strenuous physical activities. For instance, athletes drink a lot of water and sports drinks to replenish what is lost through perspiration, which keeps their bodies performing at peak level.
As the Centers for Disease Control and Prevention explains, in addition to hydration, water serves other important purposes such as helping the body to stay at a comfortable temperature. Water supports cells, tissues and joints while assisting the body to run like a well-oiled machine. Water is also needed to form tears and saliva.
About.com points out that eating fresh fruits and vegetables is another way to get water into the body to meet daily minimum requirements for adequate hydration.