High Blood Pressure

Overview

High blood pressure is a condition that increases your risk of heart disease, stroke, heart failure, kidney disease, and other health problems. Blood pressure is the force your blood applies to the walls of your arteries as it circulates throughout your body. High blood pressure occurs when this force is raised above normal levels. High blood pressure is also called hypertension.

While it’s normal for blood pressure to change—rise and fall—throughout the day, sustained high blood pressure puts you at greater risk for serious health conditions.

The Centers for Disease Control and Prevention (CDC) estimates that about one in three (or about 31 percent) of adults in the United States has high blood pressure. The CDC also estimates that 25 percent of U.S. adults have prehypertension, or higher than normal blood pressure, a condition that puts you at greater risk for high blood pressure.

Complications

High blood pressure can result in hardening of the arteries, which decreases the flow of blood and oxygen to the heart. When the heart isn’t receiving enough blood or oxygen, you’re at risk for chest pain (angina), heart failure, or heart attack. High blood pressure is also a risk factor for kidney disease, aneurysms, and bursting or bleeding of blood vessels in the eyes, which can lead to vision changes or blindness.

Understanding Blood Pressure: What the Numbers Mean

When you have your blood pressure measured, the reading will include two numbers: the first is called systolic, and the second is call diastolic. Systolic pressure is the pressure in your blood vessels when your heart beats; diastolic pressure is the pressure in your blood vessels when your heart rests between beats. The units used to measure blood pressure are millimeters of mercury, or mmHg. An example of a blood pressure reading is “120 over 80,” which can be written as “120/80 mmHg.”

Levels of blood pressure are as follows:

Normal: systolic less than 120 mmHg and diastolic less than 80 mmHg
Prehypertension: systolic 120-139 mmHg and diastolic 80-89 mmHg
High: systolic 140 mmHg or higher and diastolic 90 mmHg or higher

Causes

Blood pressure tends to rise with age (but, as you’ll learn later in Prevention, there are steps you can take to prevent a rise or control levels). As well, certain medical problems may contribute to high blood pressure; these include chronic kidney disease, thyroid disease, and sleep apnea. High blood pressure is also common among people with diabetes. As well, some medicines can raise blood pressure; these include asthma medicines, cold medicines, and for some women, birth control pills or hormone therapy. It’s also possible that a woman’s blood pressure may rise during pregnancy.

Symptoms

People with high blood pressure rarely have symptoms. It can only be detected when a healthcare professional measures your blood pressure.

Testing and Diagnosis

A blood pressure test, which is performed by your doctor or nurse, is used to diagnose high blood pressure. Your doctor or nurse will check your blood pressure on several occasions to make sure that the reading is correct.

A diagnosis of high blood pressure is made with a blood pressure level of 140/90 mmHg or higher over time. For people with diabetes or kidney disease, 130/80 mmHg indicates high blood pressure.

A blood pressure test is simple and painless. Your doctor or nurse will use a gauge, a stethoscope or electronic sensor, and a blood pressure cuff, which is placed around your arm. Before the test, do the following to avoid a short-term raise in blood pressure and ensure an accurate reading: don’t drink coffee or smoke, go to the bathroom before the test, and sit still for five minutes before the test.

Risks

Several conditions, behaviors, and personal characteristics may raise your risk of developing high blood pressure. These include:

Prehypertension—People with prehypertension don’t have blood pressure levels that are considered high, but their levels are higher than normal.
Diabetes—High blood pressure is common in people with diabetes—about 60 percent have high blood pressure.
Diet—A diet that’s too high in sodium (salt) can raise your blood pressure. Processed foods and restaurant foods tend to be particularly high in sodium. As well, your blood pressure can increase as a result of not eating enough potassium, which is found in fruits and vegetables.
Weight—If you’re overweight or obese, you’re at greater risk for high blood pressure.
Lack of physical activity—Inactivity can lead to weight gain, which—as noted above—is associated with high blood pressure.
Alcohol—Drinking too much alcohol can raise your blood pressure.
Tobacco use—Smoking is a risk factor for high blood pressure.
Age—Your blood pressure may rise as you age.
Race or ethnicity—Compared with Whites, African Americans are more likely to develop high blood pressure.
Family history—If high blood pressure runs in your family, you may be at greater risk. This risk increases if you have a family history and you smoke, eat a poor diet, are overweight, or inactive.

Treatment

Treatment for high blood pressure involves both medicines and lifestyle changes. Once you’ve been diagnosed with high blood pressure and begin treatment, you’ll likely have to continue treatment for the rest of your life. Staying on treatment will help you avoid the health risks associated with high blood pressure and maintain a full, active life. The goal of treatment is generally to get blood pressure below 140/90 mmHg and maintain that level. For people with diabetes or kidney disease, target blood pressure is 130/80 mmHg.

Medicines

Several types of medicines are used to lower high blood pressure. They each work in different ways and are often combined. Medicines used to lower blood pressure include:

Diuretics: These medicines help you flush excess water and salt from your body, which lowers the amount of fluid in your blood.
Beta blockers: These medicines help decrease the speed and force of your heartbeat. As a result, less blood is pumped through your blood vessels and blood pressure goes down.
ACE inhibitors: These medicines keep your body from making the hormone angiotensin II, which causes blood vessels to narrow.
Angiotensin II Receptor Blockers: These medicines protect your blood vessels from the effects of angiotensin II, thereby allowing blood vessels to relax and widen.
Alpha blockers: These medicines allow blood to flow more freely through your blood vessels by reducing nerve impulses to tighten them.
Alpha-beta blockers: These medicines work as both alpha and beta blockers, which are described above.
Nervous system inhibitors: These medicines increase nerve impulses from the brain to relax and widen blood vessels.
Vasodilators: These medicines relax the muscles in the blood vessel walls.

Lifestyle Changes

The lifestyle changes that can help you control high blood pressure can also help you prevent the condition. They include maintaining a healthy diet and a healthy weight, getting enough physical activity, not smoking, and managing stress. For more details about these healthy habits, see Prevention below.

Prevention

Fortunately, there are lifestyle choices you can make to keep your blood pressure at normal levels and thereby reduce your risk of health conditions associated with high blood pressure like heart disease and stroke. If you have high blood pressure, making these choices may help you lower it. Here are some of the things you can do:

Eat a healthy diet. This involves eating a lot of fruits and vegetables and foods that are low in saturated fat and cholesterol. Avoid sodium by limiting processed foods, eating fewer meals in restaurants, and refraining from adding salt to your food. The general recommended daily sodium intake is less than 2,300 mg for adults and less than 1,500 mg for people over 40, African Americans, and people with high blood pressure.
Maintain a healthy weight. Talk to your doctor about what a healthy weight is for you.
Be physically active. According to the Surgeon General, you should aim for at least 30 minutes of moderate exercise most days of the week.
Don’t smoke.
Limit alcohol use. A general recommendation is no more than one drink per day for women and two drinks per day for men.
Get your blood pressure checked. Remember that high blood pressure often has no symptoms. It’s therefore important to see a healthcare provider for regular blood pressure checks so that you can detect any changes.
Prevent and manage diabetes. Given the prevalence of high blood pressure (about 60 percent) among people with diabetes, reducing your risk of diabetes or managing the condition if you do have it can also reduce your risk of high blood pressure. Measures to both prevent and manage diabetes include eating a healthy diet, maintaining a healthy weight, and staying physically active.
Manage and learn to cope with stress. Find ways to relax and relieve stress, such as physical activity, yoga, or meditation.

Resources

The American Heart Association

The American Society of Hypertension

The National Heart Lung and Blood Institute

The Centers for Disease Control and Prevention

SOURCES

High Blood Pressure. The Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/bloodpressure/. (Accessed October 2010).

High Blood Pressure. The National Heart Lung and Blood Institute website. Available at: http://www.nhlbi.nih.gov/health/dci/Diseases/Hbp/HBP_All.html. (Accessed October 2010).