BLOOD PRESSURE that remains consistently elevated. Health experts estimate that 25 percent of American adults-about 75 million people have hypertension, though about half of them do not know it. Hypertension, also called high blood pressure, is a leading cause of STROKE and KIDNEY disease, and a key factor in many heart attacks.
Stroke kills nearly 150,000 Americans each year, making it the third leading cause of death in the United States, and disables about a million others. Yet as many as 80 percent of strokes are preventable through controlling blood pressure. Early diagnosis of hypertension to prevent stroke is a goal of the U.S. preventive health initiative HEALTHY PEOPLE 2010.
Loss of feeling or movement and blurred or dimmed vision, especially on only one side of the body, and difficulty forming or understanding words, are early warning signs of STROKE that require emergency medical evaluation.
Hypertension has numerous effects on the cardiovascular system, and over time alters the function of the HEART as well as the distribution of blood throughout the body. Hypertension in combination with ATHEROSCLEROSIS, the most common form of CARDIOVASCULAR DISEASE (CVD) in the United States, can be particularly damaging or lethal. In combination with DIABETES, hypertension significantly raises the risk for kidney failure and RETINOPATHY of diabetes, in which the tiny blood vessels in the RETINA rupture, causing blindness.
Hypertension has no symptoms, which is why regular blood pressure monitoring is so important. For many people, the first indication of hypertension is stroke or kidney disease, the two leading complications of hypertension. Hypertension may also trigger HEART ATTACK. Occasionally people who have severely elevated blood pressure experience headaches.
Healthy blood pressure is a systolic reading below 120 millimeters of mercury (mm Hg) and a diastolic reading below 80 mm Hg. Persistent readings above these levels for either systolic or diastolic pressure constitute hypertension. Generally the doctor takes several blood pressure readings at different times of the day over a span of time before diagnosing hypertension. A diagnosis of hypertension follows a minimum of three elevated readings. Many people are anxious or nervous when visiting the doctor, sometimes resulting in a phenomenon doctors call “white coat hypertension.” An assessment of vital signs, including blood pressure, usually takes place at the start of the health-care visit; when blood pressure is elevated, the doctor may take a measurement again at the end of the visit when the person’s anxiety level has dropped.
|Prehypertension||120-139 mm Hg||80-89 mm Hg|
|Stage 1 hypertension||140-159 mm Hg||90-99 mm Hg|
|Stage 2 hypertension||160 mm Hg and above||100 mm Hg and above|
Lifestyle modification is the first and the foundational treatment approach for hypertension. Intervention at the prehypertension level can bring blood pressure under control before it becomes a health problem. Overweight or OBESITY causes or exacerbates much hypertension, so often the doctor’s first recommendation is weight loss through increased physical activity and changes in eating habits that reduce overall caloric intake. Further dietary modifications often include reducing sodium consumption, as high amounts of dietary sodium cause the body to maintain fluid. This increases blood volume and, correspondingly, blood pressure. Doctors also recommend reducing dietary fat, especially saturated fat, and cholesterol to reduce the risk for HYPERLIPIDEMIA and atherosclerosis. Atherosclerosis narrows and stiffens the arteries, increasing the resistance blood encounters, and is a significant factor in hypertension.
The mainstay of treatment for hypertension is medication. There are numerous classifications and kinds of drugs that can lower blood pressure through different actions and mechanisms. Often the doctor will combine medications in a multifaceted approach. Many of the medications used to treat hypertension also treat other cardiovascular conditions. Cardiologists often prescribe beta blockers and calcium channel blockers, for example, to treat ARRHYTHMIA, CARDIOMYOPATHY, and HEART FAILURE. Because cardiovascular disease is often a constellation of conditions, this is an effective approach for preventing further cardiovascular disease from developing.
The decision to begin medication for hypertension depends on the blood pressure elevation and other cardiovascular disease or risk factors. Doctors may choose to initiate antihypertensive medication therapy for stage 1 hypertension in people who have multiple cardiovascular risks, yet try three to six months of lifestyle modification for people who have few or no other known cardiovascular risks. Medication needs may change if other health conditions develop or cardiovascular status changes. On the positive side, lifestyle modifications in combination with medication therapy often can reduce or eliminate the need for medication in people who have stage 1 hypertension and occasionally in people who have stage 2 hypertension.
|KINDS OF MEDICATIONS TO TREAT HYPERTENSION|
|angiotensin II receptor blockers (ARBs)||angiotensin-converting enzyme (ACE) inhibitors|
|beta blockers||calcium channel blockers|
The leading risk factors for hypertension are age, cigarette smoking, dietary habits, and physical inactivity. Health conditions such as obesity, diabetes, and atherosclerosis further increase the risk for hypertension. Health experts recommend all adults over age 40 undergo annual blood pressure screening, with more frequent screening for people who have increased risk. Daily physical exercise such as walking helps control weight as well as maintain cardiovascular efficiency, reducing risk across the spectrum of cardiovascular disease.
See also CARDIOVASCULAR DISEASE PREVENTION; DIET AND CARDIOVASCULAR HEALTH; LIFESTYLE AND CARDIOVASCULAR HEALTH; PHYSICAL EXERCISE AND CARDIOVASCULAR HEALTH; SMOKING CESSATION.
Resource: Facts On File Encyclopedia Of Health And Medicine
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