Most people believe that drinking eight glasses of water a day is all it takes to keep their cardiovascular system running smoothly. You have probably been told that if your urine is pale yellow and you drink water whenever you feel thirsty, your blood vessels have everything they need. Unfortunately, this advice overlooks the actual physiology of your arteries. Your cardiovascular system does not run on simple tap water or distilled water. It runs on a complex, highly regulated fluid matrix known as blood plasma. How that fluid interacts with the inner lining of your blood vessels determines whether your arteries stay supple and flexible, or whether they turn stiff, inflamed, and prone to plaquing.