What Is High Blood Pressure?

High blood pressure directly increases the risk of coronary heart disease (which leads to heart attack) and stroke, especially when it's present 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 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.

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What Causes High Blood Pressure?

These problems can usually be corrected. For example, doctors can repair a narrowed artery that supplies blood to a kidney. Most of these problems can be ruled out by a careful history, a physical examination and a few tests. Special tests are sometimes needed, but you don't usually have to stay in the hospital.

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 major risk factor for stroke, heart attack, heart failure 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 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:

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, have it evaluated.

Why Should I Care?

High blood pressure is the No. 1 modifiable risk factor for  stroke . It also contributes to heart attacks, heart failure, kidney failure and atherosclerosis (fatty buildups in arteries). In some cases, it can cause blindness. The relationship of blood pressure levels to the risk of cardiovascular disease is continuous, consistent and independent of other risk factors. That means the higher your blood pressure, the greater your risk of heart attack, heart failure, stroke and kidney disease.

For example*:

A 50 year-old man of normal body mass with blood pressure of 146/86 (high) has:

than if he had normal blood pressure (less than 120/80).

A 40-year-old woman of normal body mass with blood pressure 146/86 (high) has:

than if she had normal blood pressure (less than 120/80).

According to studies conducted between 1999 and 2004, about 40 percent of Americans over 18 with high blood pressure were not currently under treatment and almost 65 percent did not have their blood pressure under control. The estimated direct and indirect cost of high blood pressure in the United States for 2008 is $69.4 billion.  Read our most recent statistics for more.

Arteries  and arterioles (small arteries) also suffer the effects of higher blood pressure. As you grow  older, your arteries will harden and become less elastic. This occurs gradually in all people, even if they don't have high blood pressure. But having high blood pressure tends to speed up this process.

Arterial damage is bad because hardened or narrowed arteries may not be able to supply the amount of blood the body’s organs need. And if the body's organs don't get enough blood (and the oxygen and nutrients it delivers), they can't work properly. Another risk is that a  blood clot  may lodge in an artery narrowed by fatty deposits, depriving part of the body of its normal blood supply.

The good news is, blood pressure is easily controllable through lifestyle changes — eating heart-healthy diet, limiting alcohol, avoiding tobacco smoke, controlling your weight and getting regular physical activity — and medication, if your doctor recommends. Learn more about how to control your blood pressure. If you have high blood pressure, follow your doctor's advice. Most high blood pressure can't be cured, but it usually can be controlled. And its effects can be prevented or reduced — if it's treated and controlled early, and kept under control.

Pledge to control your risk of heart attack, stroke and other diseases by controlling your blood pressure.

*Source:  Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7)

What Can I Do?

High blood pressure is a lifelong disease. It can usually 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 reducing the fat (particularly saturated fat) in your diet, eating less salt and changing your lifestyle by losing weight and getting regular physical activity.
• 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.

Pledge to control your risk of heart attack, stroke and other diseases by controlling your blood pressure.

Be sure to look at our patient education sheets on high blood pressure. These can be printed out and taken to your physician. There are spaces for you to ask questions and for your physician to write special instructions.

What Is High Blood Pressure?
What Is High Blood Pressure Medicine?
How Can I Reduce High Blood Pressure?

Spanish Patient Education Sheets
¿Qué es la presión alta?
¿Cómo puedo bajar la presión alta?