Medical

High Blood Pressure

Many people have high blood pressure for years without knowing it. Uncontrolled high blood pressure can lead to stroke, heart attack, heart failure or kidney failure. The only way to tell if you have high blood pressure is to have your blood pressure checked. According to recent estimates, one in four U.S. adults has high blood pressure, but because there are no symptoms, nearly one-third of these people don't know they have it. This is why high blood pressure is often called the "silent killer."

What Is High Blood Pressure?

Blood pressure is the force in the arteries when the heart beats (systolic pressure) and when the heart is at rest (diastolic pressure). It's measured in millimeters of mercury (mm Hg). High blood pressure (or hypertension) is defined in an adult as a blood pressure greater than or equal to 140 mm Hg systolic pressure or greater than or equal to 90 mm Hg diastolic pressure.

High blood pressure directly increases the risk of coronary heart disease (which leads to heart attack) and stroke, especially along with other risk factors.

High blood pressure can occur in children or adults, but it's more common among people over age 35. It's particularly prevalent in African Americans, middle-aged and elderly people, obese people, heavy drinkers and women who are taking birth control pills. It may run in families, but many people with a strong family history of high blood pressure never have it. People with diabetes mellitus, gout or kidney disease are more likely to have high blood pressure, too.

American Heart Association recommended blood pressure levels

*Your doctor should evaluate unusually low readings.

How does high blood pressure develop?

Your heart pumps blood through the body's arteries. The large arteries that leave your heart taper into smaller arteries called arterioles. The arterioles then taper into smaller vessels called capillaries, which supply oxygen and nutrients to all the organs of your body. The blood then returns to your heart through the veins.

Certain nerve impulses cause your arteries to dilate (become larger) or contract (become smaller). If these vessels are wide open, blood can flow through easily. If they're narrow, it's harder for the blood to flow through them, and the pressure inside them increases. Then high blood pressure may occur. When this happens, your heart becomes strained and blood vessels may become damaged. Changes in the vessels that supply blood to your kidneys and brain may cause these organs to be affected.

Your heart, brain and kidneys can handle increased pressure for a long time. That's why you can live for years without any symptoms or ill effects. But that doesn't mean it's not hurting you. High blood pressure is a key risk factor for a stroke, heart attack and kidney failure.

What does high blood pressure do to your body?

High blood pressure adds to the workload of your heart and arteries. Your heart must pump harder, and the arteries carry blood that's moving under greater pressure. If high blood pressure continues for a long time, your heart and arteries may not work as well as they should. Other body organs may also be affected. There is increased risk of stroke, congestive heart failure, kidney failure and heart attack. When high blood pressure exists with obesity, smoking, high blood cholesterol levels or diabetes, the risk of heart attack or stroke increases several times.

What about low blood pressure?

Within certain limits, the lower your blood pressure reading is, the better. In most people, blood pressure isn't too low until it produces symptoms, such as lightheadedness or fainting. In certain disease states, it's possible for blood pressure to be too low. Examples include:

• Certain nerve or endocrine disorders
• Prolonged bed rest
• Decreases in blood volume due to severe bleeding (hemorrhage) or dehydration

Blood pressure less than 120/80 mm Hg is generally considered ideal. Levels higher than this increase your risk for cardiovascular disease. If you have unusually low blood pressure, you need to have it evaluated.

Am I at Risk?

If you're an adult and your blood pressure is 140/90 mm Hg or above, you have hypertension and are at risk for heart disease, stroke and other medical problems. See a doctor and learn how to manage your blood pressure and how often to have it checked. High blood pressure has no symptoms, so if you haven't had it checked in a while, make an appointment now. One in four adult Americans has high blood pressure, and nearly one-third of them don't know they have it.

Factors that contribute to high blood pressure

Medical science doesn't understand why most cases of high blood pressure occur, so it's hard to say how to prevent it. However, we do know of several factors that may contribute to high blood pressure and put you at increased risk for heart attack and stroke.

Controllable risk factors

• Obesity — People with a body mass index (BMI) of 30.0 or higher are more likely to develop high blood pressure.
• Eating too much salt — A high sodium intake increases blood pressure in some people.
• Drinking too much alcohol — Heavy and regular use of alcohol can increase blood pressure dramatically.
• Lack of physical activity — An inactive lifestyle makes it easier to become overweight and increases the chance of high blood pressure.
• Stress — This is often mentioned as a risk factor, but stress levels are hard to measure, and responses to stress vary from person to person.

Uncontrollable risk factors

• Race — African Americans develop high blood pressure more often than whites, and it tends to occur earlier and be more severe.
• Heredity — If your parents or other close blood relatives have high blood pressure, you're more likely to develop it.
• Age — In general, the older you get, the greater your chance of developing high blood pressure. It occurs most often in people over age 35. Men seem to develop it most often between age 35 and 55. Women are more likely to develop it after menopause.

What Can I Do?

High blood pressure is a lifelong disease. It can be controlled but not cured. Once you begin to manage it and start a treatment program, maintaining a lower blood pressure is easier. By controlling your high blood pressure, you'll lower your risk of diseases like stroke, heart attack, heart failure and kidney disease. You can do it!

The first thing to do is to have your blood pressure checked. If you have high blood pressure, you can do a lot to reduce it. Work with your doctor to determine the best treatment for you.

• It may include a lower-fat diet, a low-salt diet, and changes in your living habits such as losing weight and getting more exercise.
• Quitting smoking is also important to reduce your overall risk for heart attack and stroke.
• Your doctor may recommend reducing how much alcohol you drink.
• Many medicines also can help reduce and control high blood pressure. Your doctor will decide whether you need medicine in addition to dietary and lifestyle changes.

Most of this information was found on the American Heart Association website.

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