What is blood pressure?

Blood is carried from the heart to all parts of your body in vessels called arteries. Blood pressure is the force of the blood pushing against the walls of the arteries. Each time the heart beats (about 60-70 times a minute at rest), it pumps out blood into the arteries. Your blood pressure is at its highest when the heart beats, pumping the blood. This is called systolic pressure. When the heart is at rest, between beats, your blood pressure falls. This is the diastolic pressure.

How is it measured?

A simple machine called a sphygmomanometer is used to painlessly measure blood pressure. This equipment is now available in most pharmacies for at-home use. Your doctor, nurse, or pharmacist can help you check the monitor and teach you how to use it correctly. You also may ask for their help in choosing the right blood pressure monitor for you. Around age 55, systolic blood pressure (the top reading) begins to rise. Middle aged Americans have a 90% chance of developing high blood pressure, so blood pressure checks at least every two years are important as is weight control and following any diet and medication program prescribed by the physician to control the blood pressure.

What do the blood pressure readings mean?

Blood pressure is always given as two numbers, the systolic and diastolic pressures. Both are important. Usually they are written one above or before the other, such as 120/80 mmHg. The top number is the systolic and the bottom the diastolic. When the two measurements are written down, the systolic pressure is the first or top number, and the diastolic pressure is the second or bottom number (example, 120/80). If your blood pressure is 120/80, you say that it is "120 over 80."

For most of your waking hours, your blood pressure stays pretty much the same when you are sitting or standing still. Your blood pressure reading should be lower than 120/80. When the level stays high, at 140/90 or higher, you have high blood pressure. With high blood pressure, the heart works harder, your arteries take a beating, and your chances of a stroke, heart attack, and kidney problems are greater.

There are two levels of high blood pressure: Stage 1 and Stage 2

Categories for Blood Pressure Levels in Adults*

(In mmHg, millimeters of mercury)

If the top number is 140 or higher, you are more likely to develop cardiovascular and kidney diseases.

Who is at risk for high blood pressure?

Nearly 1 in 3 adults in the United States has high blood pressure. In the U.S., it occurs more often in African Americans. Compared to other groups, African Americans:

• Tend to get high blood pressure earlier in life
• Usually have more severe high blood pressures
• Have a higher death rate from stroke, heart disease, and kidney failure.

The risk for high blood pressure increases if you:

• Are overweight
• Are a man over the age of 45
• Are a woman over the age of 55
• Have a family history of high blood pressure

Other things that can raise blood pressure include:

• Eating too much salt
• Drinking too much alcohol
• Not eating enough potassium
• Not exercising
• Taking certain medicines
• Stress that is long-lasting

Why is high blood pressure a concern?

High blood pressure is called "the silent killer" because it usually has no symptoms. Some people may not find out they have it until they have trouble with their heart, brain, or kidneys. High blood pressure is the most important risk factor for stroke and is a major risk factor for heart and kidney disease and congestive heart failure.

When high blood pressure is not found and treated, it can cause:

• The heart to get larger, which may lead to heart failure.
• Small bulges (aneurysms) to form in blood vessels
• Common locations are the main artery from the heart (aorta), arteries in the brain, legs, and intestines, and the artery leading to the spleen.
• Blood vessels in the kidney to narrow, which may cause kidney failure.
• Arteries throughout the body to "harden" faster, especially those in the heart, brain, kidneys, and legs. This can cause a heart attack, stroke, kidney failure, or amputation of part of the leg.
• Blood vessels in the eyes to burst or bleed, which may cause vision changes and can result in blindness.

How is blood pressure monitored and treated?

Your health care provider will advise you how often to obtain a blood pressure check. Blood pressure readings are usually taken when you are sitting or lying down and relaxed. Below are things you can do before having your blood pressure taken:

. Do not drink coffee or smoke cigarettes 30 minutes before having your blood pressure taken.

• Wear short sleeves.
• Go to the bathroom before the reading. Having a full bladder can change your blood pressure reading.
• Sit for 5 minutes before the test.

Below are additional things to do when taking your blood pressure at home:

• Sit with your back supported and your feet flat on the floor.
• Rest your arm on a table at the level of your heart.
• Take two readings, at least 2 minutes apart, and average the results.

Usually, the goal is to keep your blood pressure below 140/90 (130/80 if you have diabetes or chronic kidney disease). Ask your doctor what your blood pressure goal should be.

Some people can prevent or control high blood pressure by changing to healthier habits, such as:

• Eating healthy foods that include fruits, vegetables, and low-fat dairy products
• Cutting down on salt and sodium in the diet
• Losing excess weight and staying at a healthy weight
• Staying physically active (for example, walking 30 minutes a day)
• Limiting alcohol intake.

Sometimes blood pressure stays too high even when a person makes these kinds of healthy changes. In that case, it is necessary to add medicine to help lower blood pressure. Medicines will control your blood pressure but they cannot cure it. You will need to take high blood pressure medicine for a long time.

Blood pressure medicines work in different ways to lower blood pressure. Often, two or more drugs work better than one. Some drugs lower blood pressure by removing extra fluid and salt from your body. Others affect blood pressure by slowing down the heartbeat, or by relaxing and widening blood vessels.

Below are the types of medicines used to treat high blood pressure:

• Diuretics are sometimes called "water pills." They work by helping your kidneys flush excess water and salt from your body. This reduces the amount of fluid in your blood, and your blood pressure goes down. There are different types of diuretics. They are often used along with other high blood pressure medicines and may be combined with another medicine in one pill.
• Beta blockers help your heart beat slower and with less force. Your heart pumps less blood through the blood vessels, and your blood pressure goes down.
• Angiotensin converting enzyme (ACE) inhibitors keep your body from making a hormone called angiotensin II, which normally causes blood vessels to narrow. ACE inhibitors prevents this narrowing so your blood pressure goes down.
• Angiotensin II Receptor Blockers (ARBS) are newer blood pressure drugs that protect your blood vessels from angiotensin II. As a result, the blood vessels relax and become wider, and your blood pressure goes down.
• Calcium channel blockers (CCBs) keep calcium from entering the muscle cells of your heart and blood vessels. This causes blood vessels to relax, and your blood pressure goes down.
• Alpha blockers reduce nerve impulses that tighten blood vessels, allowing blood to pass more easily and causing blood pressure to go down.
• Alpha-beta blockers reduce nerve impulses to blood vessels the same way alpha blockers do, but they also slow the heartbeat, as beta blockers do. As a result, blood pressure goes down.
• Nervous system inhibitors relax blood vessels by controlling nerve impulses from the brain. This causes blood vessels to become wider and blood pressure to go down.
• Vasodilators open blood vessels by directly relaxing the muscle in the vessel walls, causing blood pressure to go down.

Information about specific medicines can be found using our Drug Reference Center; see also the Drug Interaction Center

Older Adults and High Blood Pressure A common form of high blood pressure in older adults is isolated systolic hypertension (ISH). ISH is high blood pressure, but only the top (systolic) number is high (140 or higher). ISH can be as harmful as high blood pressure in which both numbers are high.

ISH is the most common form of high blood pressure for older Americans. About 2 out of 3 people over age 60 with high blood pressure have ISH. You may have ISH and feel fine. As with other types of high blood pressure, ISH often causes no symptoms. To find out if you have ISH--or any type of high blood pressure--get your blood pressure checked.

If not treated, ISH can cause damage to your arteries and to body organs. ISH is treated the same way as high blood pressure in which both systolic and diastolic pressures are high: by making changes in your health habits and with blood pressure medicines, if needed.

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