Tring to do the right thing by drinking eight full glasses of water everyday may do little more than making a person run to the bathroom, a researcher said. Newspaper articles, health and beauty magazines all advise drinking at least eight full glasses of water a day, totalling 64 ounces for optimal health. And the approach called "8 x 8" by proponent. But doctor Heinz Valtin, a Dartmouth medical school in New Hampshire said "there is no scientific evidence to back up the advice which help create huge market for bottled water". "After ten month of careful searching, I have found no scrientific evidence that support 8 x 8", Valtin, a kidney specialist who is in textbooks on the subjects of human water balance, said in a telephone interview. Writing in the American Journal of Physiology, Walton said that people forget that the food they eat also contains some water. I did 46 years of research on that system--the osmoregulatory system. That system is so precise and so fast that I find impossible to believe. The evolution left us with a chronic water deficit, Valtin said. If a person gets low on fluid, the body compensates by bringing fluid back out of the kidneys and by slowing the lots of water through the skin, Valtin said. Thus takes in long before the dehydration starts, he added.