High Blood Pressure



According to recent estimates, nearly one in three 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. In fact, 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. This is why high blood pressure is often called the "silent killer." The only way to tell if you have high blood pressure is to have your blood pressure checked.

Get the facts on high blood pressure and how to live a heart-healthier life. Find out how you can reduce your risks for heart attack and stroke with proper monitoring by a healthcare provider and simple lifestyle changes, even if you have high blood pressure.

About High Blood Pressure





When the heart beats, it pumps blood to the arteries and creates pressure in them. This pressure (blood pressure) results from two forces. The first force is created as blood pumps into the arteries and through the circulatory system. The second is created as the arteries resist the blood flow.

If you're healthy, your arteries are muscular and elastic. They stretch when your heart pumps blood through them. How much they stretch depends on how much force the blood exerts.

Your heart beats about 60 to 80 times a minute under normal conditions. Your blood pressure rises with each heartbeat and falls when your heart relaxes between beats. Your blood pressure can change from minute to minute, with changes in posture, exercise or sleeping, but it should normally be less than 120/80 mm Hg for an adult. Blood pressure that stays between 120-139/80-89 is considered prehypertension and above this level (140/90 mm Hg or higher) is considered high (hypertension). Your doctor may take several readings over time before deciding whether your blood pressure is high.

What do blood pressure numbers indicate?

The higher (systolic) number represents the pressure while the heart is beating.
The lower (diastolic) number represents the pressure when the heart is resting between beats.
The systolic pressure is always stated first and the diastolic pressure second. For example: 117/76 (117 over 76); systolic = 117, diastolic = 76
What Causes High Blood Pressure?


Kidney abnormality
A structural abnormality of the aorta (large blood vessel leaving the heart) existing since birth
Narrowing of certain arteries
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:

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, have it evaluated.