What Is Blood Pressure?

Blood is carried through the body by a network of blood vessels known as arteries and veins. Arteries carry oxygen-rich blood from the heart to the body. Veins carry blood back from the body to the heart. As blood passes through the body, it carries oxygen to the organs and removes waste.

Blood pressure is the force of blood against the walls of the blood vessels. A blood pressure reading has two numbers separated by a slash—the systolic pressure and diastolic pressure:

• The systolic pressure (the top or first number) is the force of blood in the arteries when your heart contracts.

• The diastolic blood pressure (the bottom or second number) is the force of blood in the arteries when your heart relaxes.

How High Is Too High? The chart below shows different blood pressure readings and how they are classified for adults age 18 years and older. Find your systolic and diastolic pressure readings to see whether your blood pressure is normal. Category Systolic (mm Hg) Diastolic (mm Hg) Optimal Less than 120 Less than 80 Normal Less than 130 Less than 85 High normal 130-139 85-89 Hypertension More than 140 More than 90 Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Sixth Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI). Bethesda, Maryland: National Heart, Lung, and Blood Institute, 1997

Every woman should have her blood pressure checked yearly—the test is simple and painless. To measure your blood pressure, an inflatable cuff that is pumped with air is wrapped around your upper arm. Your pressure reading is taken while the cuff is squeezing your arm.

How High Blood Pressure Affects Your Body

High blood pressure can have a number of causes and often runs in families. People with high blood pressure often have no symptoms and feel fine. Long before high blood pressure causes symptoms, however, it can damage vital organs in your body. If it is not treated, high blood pressure can lead to very serious health problems.

The Blood Vessels

Long-term high blood pressure can damage blood vessels. The buildup of plaque also can lead to a narrowing of blood vessels. Plaque is a fatty substance that forms in the arteries when too much cholesterol is present. Over the years, plaque causes the arteries to narrow and harden. This is called atherosclerosis. The combination of atherosclerosis and high blood pressure sets the stage for stroke and heart attack.

The Heart

As blood pressure rises, the heart has to work harder to deliver oxygen to the tissues. Over time, the heart enlarges and may have trouble doing its work. This can lead to heart failure.

The Brain

High blood pressure can cause a blood vessel to the brain to burst and lead to stroke. Brain cells in that part of the brain may die. A stroke that continues for a few minutes can cause permanent brain damage or death. Depending on the part of the brain affected, signals from the brain to the body can be disrupted and can affect speech, movement, and other bodily functions.

The Kidneys

The kidneys filter the blood to remove waste from your body. The blood vessels in the kidneys can be easily damaged by high blood pressure. When the kidneys are not working normally, their ability to control salt and water balance in the body is disrupted. This can lead to kidney failure.

The Eyes

High blood pressure can also narrow the blood vessels in the eyes. This can cause your vision to become worse and may even lead to blindness.

Risks for High Blood Pressure

Lifestyle habits can increase your risk for high blood pressure. Women who are overweight, are not physically active, smoke cigarettes, or drink large amounts of alcohol are more at risk. Diet and stress also play a role.

There are factors, however, that increase the risk for high blood pressure that are not related to lifestyle habits and cannot be changed:

• Age—Blood pressure goes up with age, and high blood pressure occurs most often among women over 40.

• Race—High blood pressure is more common in African Americans than in any other racial group.

• Family history—High blood pressure tends to run in families.

• Medical conditions—Certain diseases, such as diabetes and kidney disease, can be linked to high blood pressure.

Managing High Blood Pressure

You can lessen your risk of high blood pressure and its long-term effects by adopting a healthy lifestyle. The following methods may help lower your blood pressure:

• Lose weight—If you are overweight, losing weight is the single most effective way to reduce your blood pressure. Even as little as a 5-pound weight loss can make a difference.

• Exercise regularly—Daily exercise lowers your blood pressure. You can benefit from doing moderate aerobic exercise, such as brisk walking, swimming, or bicycling, for at least 30 minutes a day.

• Quit smoking—Cigarette smoking is a major risk for high blood pressure and heart disease. When you quit smoking, the benefits begin right away.

• Limit alcohol drinking—Heavy alcohol drinking (more than two drinks a day) is linked to an increase in blood pressure.

• Cut back on salt—Heavy salt (sodium) consumption can increase blood pressure in some people. Some people with high blood pressure are "salt sensitive"—their blood pressure rises when on a high-salt diet and falls when on a low-salt diet.

• Change your diet—If your high blood pressure is linked to atherosclerosis, a low cholesterol diet may be helpful.

• Relieve stress—Stress that is not managed or relieved can affect your health. Relaxation techniques, exercise, or getting professional counseling can help you cope with stress.

Medical Treatment

Your doctor may prescribe medications to lower your high blood pressure. He or she will discuss with you which ones are best for your condition.

Medications to treat high blood pressure can have side effects. If you think you are having any side effects, talk to your doctor—it's possible that you can try different therapy. Do not stop taking your medication—this could cause your blood pressure to rise to a very high level. It is important to continue taking your medication even when you are feeling healthy.

Finally...

As we age, our blood pressure tends to rise. It is important to have your blood pressure checked regularly. If your blood pressure is high, see your doctor to develop a plan of managing it that is right for you. If your doctor prescribes medications, stick with them. Keeping your blood pressure at normal levels can help you avoid other serious health conditions.

Glossary

Atherosclerosis: Narrowing and clogging of the arteries by a buildup of plaque deposited in vessel walls; also called "hardening of the arteries."