High blood pressure is a blood pressure reading of 140/90 mmHg or higher. Both numbers are important. Nearly one in three American adults has high blood pressure. Once high blood pressure develops, it usually lasts a lifetime. The good news is that it can be treated and controlled. High blood pressure is called "the silent killer" because it usually has no symptoms. Some people may not find out they have it until they have trouble with their heart, brain, or kidneys. When high blood pressure is not found and treated, it can cause: * The heart to get larger, which may lead to heart failure. * Small bulges (aneurysms) to form in blood vessels. Common locations are the main artery from the heart (aorta), arteries in the brain, legs, and intestines, and the artery leading to the spleen. * Blood vessels in the kidney to narrow, which may cause kidney failure. * Arteries throughout the body to "harden" faster, especially those in the heart, brain, kidneys, and legs. This can cause a heart attack, stroke, kidney failure, or amputation of part of the leg. * Blood vessels in the eyes to burst or bleed, which may cause vision changes and can result in blindness.