heart and blood vessel disorders
High Blood Pressure
Introduction
High blood pressure (hypertension) is persistently high pressure in the arteries. Often no cause for high blood pressure can be identified, but sometimes it occurs as a result of an underlying disorder of the kidneys or a hormonal disorder. Obesity, a sedentary lifestyle, stress, smoking, and excessive amounts of alcohol or sodium (salt) in the diet all can play a role in the development of high blood pressure in people who have an inherited tendency to develop it. In most people, high blood pressure causes no symptoms. Doctors make the diagnosis after measuring blood pressure on two or more occasions. People are advised to lose weight, stop smoking, and decrease the amounts of sodium and fats in their diet. Antihypertensive medications are given. To many people, the word hypertension suggests excessive tension, nervousness, or stress. In medical terms, hypertension refers to persistently high blood pressure, regardless of the cause. Because it usually does not cause symptoms for many years—until a vital organ is damaged—high blood pressure has been called the silent killer. Uncontrolled high blood pressure increases the risk of problems such as Overview of Stroke , Nearly half of adults in the United States have high blood pressure. Many people are not aware that they have high blood pressure. About 80% of adults with high blood pressure have had treatment recommended, but only about half of them actually receive treatment. High blood pressure occurs more often in non-Hispanic Black adults (58%) compared with 49% of non-Hispanic White adults and 45% of non-Hispanic Asian adults, or 39% of Hispanic adults. High blood pressure occurs more often in older adults—in about two thirds of people over the age of 65 years. People who have normal blood pressure at age 55 have a 90% risk of developing high blood pressure at some point in their life. High blood pressure is twice as common among people who have obesity as among those who do not. Changes due to aging may contribute to high blood pressure with no known cause (primary hypertension). As people age, large arteries gradually stiffen and small arteries may become partially blocked. Some experts think that this stiffening combined with the narrowing of small arteries may partly explain why blood pressure increases as people age. When blood pressure is checked, two values are recorded. The higher value reflects the highest pressure in the arteries, which is reached when the heart contracts (called systole). The lower value reflects the lowest pressure in the arteries, which is reached just before the heart begins to contract again (called diastole). Blood pressure is written as systolic pressure/diastolic pressure—for example, 120/80 mm Hg (millimeters of mercury). This reading is referred to as "120 over 80." 