Your brain is your biggest liquid asset, it is composed of more then 85 percent water. Little wonder than that if you are dehydrated. You thinking ability drops dramatically. as does the performance of your whole body. Deborah Boardly, assistant professor of health promotion and human performance at the university of Ohio in Toledos says, ''I truly believe that dehydration may be the number one nutrition problem for athletes --and possibly, people in general. Now here's the question. Why we should drink eight glass of water each day? Simple is that. To keep our brain and body in peak condition. Water is second only to oxygen in survival. A body can live for minutes without oxygen, for a few days without water. and several weeks without food. The human body is 75% water. blood is 90% water, muscles are 75% water, and bone is 25% water. Water is one of the main structures of the body. Drain you body of water and you'll be left with a few pounds of chemi