High Blood Pressure; Hypertension

What is High Blood Pressure?

When you have your blood pressure taken, your health care provider is measuring the pressure, or tension, that blood exerts on the walls of the blood vessels as it travels around the body. In a healthy person, this pressure is just enough for the blood to reach all the cells of the body, but not so much that it strains blood vessel walls.


Blood pressure is measured in millimeters of mercury (mm Hg).
· A typical normal blood pressure is 120/80 mm Hg, or "120 over 80."
· The first number represents the pressure when the heart contracts.
· The second number represents the pressure when the heart relaxes.
· Blood pressure greater than 140/90 mm Hg is considered high.

Generally, blood pressure will go up at certain times - for instance, if you smoke a cigarette, win the lottery, or witness a car crash - and will return to normal when the stressful or exciting event has passed.
But when blood pressure is high all the time, the continuous increased force on blood vessel walls can damage blood vessels and organs, including the heart, kidneys, eyes, and brain.

The medical term for high blood pressure is hypertension.


Need to Know:
Systolic and Diastolic Blood Pressure
Blood travels through blood vessels much like water through a garden hose. The blood in the vessels is under pressure just like the water in a hose when the tap is turned on.

With each heartbeat more blood is pumped into the vessels - like turning up the tap - so the pressure rises. This is the systolic blood pressure, the first number in the blood pressure measurement, which is normally around 120.
Between heartbeats, while the heart is resting, the pressure in the arteries is lower. This is the diastolic pressure, second number in the blood pressure measurement, which is normally around 80.

Indication of high blood pressure
You can increase the pressure in a hose either by turning up the tap or by putting a crimp in the hose (that is, by narrowing the hose). In this same way, the blood pressure in blood vessels will rise if fluid flows more forcefully or if the arteries are narrowed.
Pressure in a hose can be regulated either by controlling the rate at which fluid passes through it or by widening it. Likewise, the pressure in the blood vessels can be controlled, with medications that act on the heart or blood vessels and with certain lifestyle modifications.

Need to Know:
Although high blood pressure can be extremely dangerous, it usually causes no symptoms - so many people don't even realize they have it. High blood pressure can only be detected with accurate and repeated measurements of a person's blood pressure. That's one reason why it's so important to have regular medical checkups.

Even though high blood pressure can be treated safely and effectively, only about one-quarter of people who have high blood pressure take the necessary steps to keep their blood pressure within a normal range.
There are three types of hypertension:
Primary hypertension (essential hypertension). This is high blood pressure for which no cause can be found. Most people with high blood pressure (90 to 95 percent) have this type of hypertension. Doctors suspect that a combination of lifestyle, diet, heredity, age, gender, race/ethnicity, hormone levels, and other factors all contribute to high blood pressure.
Secondary hypertension (non-essential hypertension). This is high blood pressure for which a definite cause can be found. This type of high blood pressure accounts for only 5 to 10 percent of all cases of hypertension. Some of these causes are temporary or controllable - for instance, pregnancy or the use of certain medications - while others are chronic conditions like hormonal diseases, kidney disease, or head injuries.

Isolated systolic hypertension (ISH). Older people are sometimes susceptible to another form of high blood pressure, called isolated systolic hypertension. In people with this condition, blood pressure is higher than normal when the heart beats, but returns to normal in between beats of the heart. The large difference in pressure can place additional strain on artery walls.

Nice To Know:
Q. If I do not feel any symptoms, is there still a problem?

A. Most people with high blood pressure do not experience any symptoms. The presence of symptoms, such as headache or blurry vision, usually indicates severe or long-standing hypertension. However, over time, uncontrolled high blood pressure causes significant damage to important organs including the heart, kidneys, brain, and eyes. In a number of cases, this damage can lead to death. This is why high blood pressure is sometimes referred to as "the silent killer."

Facts about high blood pressure
High blood pressure is a condition in which the pressure, or tension, that blood exerts on the walls of blood vessels goes up and stays high, which can damage the blood vessels, the heart, and other organs.
It is estimated that more than 50 million Americans have high blood pressure.
High blood pressure is one of the most serious health problems in the United States; yet, because high blood pressure has no symptoms, millions of people do not even know they have it.

As many as one in four adults in the United States has high blood pressure.
High blood pressure affects people of all ages, racial and ethnic groups, and walks of life.

Doctors do not know what causes high blood pressure in 90 to 95 percent of people who have it.
High blood pressure is one of the most important risk factors for coronary heart disease.

High blood pressure is the most important risk factor for stroke, which is the third leading cause of death in the United States.
High blood pressure is a common cause of heart failure, the leading cause of death in the United States
High blood pressure is a common cause of kidney disease.

What Factors Affect Blood Pressure?
Blood pumped through blood vessels is always under pressure, much like water that is pumped through a garden hose. This pressure is highest in the arteries closest to the heart and gradually decreases as the blood travels around the body.
Blood keeps moving around the body because there are differences in pressure in the blood vessels. Blood flows from higher-pressure areas to lower-pressure areas until it eventually returns to the heart.

Hypertension is much strain on your heart

Blood pressure is controlled by three things:
1 - How fast the heart beats (heart rate). The pace at which the heart beats, or heart rate, is counted in heartbeats per minute. Generally, when heart rate increases, blood pressure rises. When heart rate decreases, blood pressure drops.
2 - A number of things affect heart rate, including the body's nervous system; chemical messengers called hormones, body temperature, medications, and diseases.
3 - How much blood the heart pumps with each beat (stroke volume). The amount of blood pumped out of a ventricle with each heartbeat is called stroke volume. When you're resting, stroke volume is about the same as the amount of blood that veins carry back to the heart. But under stressful conditions, the nervous system can increase stroke volume by making the heart pump harder.

Stroke volume can also be affected by certain hormones, drugs, and diseases, as well as increases or decreases in the amount of blood in the body, called blood volume.

Nice To Know:
You might also hear the term "cardiac output" used to describe the amount of blood that's pumped through the body. Cardiac output is simply the amount of blood pumped out of a ventricle in one minute:
Cardiac output = Heart rate x Stroke volume (amount of blood pumped with each beat)

As cardiac output increases, so does blood pressure. This is why heart rate and stroke volume are important ways for the body to control blood pressure.
How difficult it is for blood to travel around the body (peripheral resistance). The third major component that affects the blood pressure is the caliber or width of the arteries. Blood traveling in narrower vessels encounters more resistance than blood traveling through a wider vessel (its harder for water to pass through a narrow pipe than a wide pipe).
Depending on what a person is doing, the amount of blood the heart pumps varies enormously. Yet the blood pressure normally remains pretty stable. That's mainly because the body adjusts the resistance of the arteries, either widening or narrowing them as appropriate, to prevent the blood pressure from swinging wildly.

This ability to regulate the width of the blood vessels is called the peripheral resistance. Most of the resistance to blood flow in the circulation occurs in the small-diameter arteries called arterioles.
These arterioles are especially important in the immediate regulation of blood pressure. That's because they contain specialized smooth muscle in their walls that can relax or contract, allowing the blood vessel to get wider or narrower.

These changes are caused by:
· Nervous system stimulation (for example, stress, caffeine, or tobacco)
· Hormones
· Proteins
· Substances derived from the inner lining, or endothelium of blood vessels
· Substances released during the body's inflammatory response, called inflammatory chemicals
· Certain medications
· Various diseases

Nice To Know:
A group of hormones called the renin-angiotensin-aldosterone system (RAAS) is another critical player in blood pressure control. They regulate the amount of fluid in the blood, the width of the blood vessel, and the sodium and water balance by their action on the kidneys and blood vessels.
The kidneys play a vital role in long-term changes in blood pressure. The hormones act on the kidneys to control the amount of sodium and water they excrete. If too much sodium or water stays, the amount of fluid in the blood, called the blood volume, goes up. This increase in blood volume means that the heart has to pump harder to circulate more fluid, and blood pressure goes up.

Keeping The Blood Pressure Normal
Generally, a change in any factor that may cause the blood pressure to rise is balanced by a change in another factor. This is how the body keeps blood pressure in a normal range.

For example, when you begin to exercise, your heart rate increases, as does the amount of blood pumped out of the heart with each beat (the stroke volume). This would normally increase the blood pressure.
But the blood pressure remains normal because the blood vessels widen in order to increase the capacity for the extra blood being pumped while exercising. This helps offset the increase in blood pressure associated with the increase in heart rate and stroke volume associated with exercise.

On the other hand, if blood pressure suddenly drops, a series of changes restores normal blood pressure. These include short-term increases in heart rate, the strength of the heart's contractions, and peripheral resistance. Over a longer period, blood volume also increases due to the actions of hormones on the kidneys.

Pulse Pressure
There is another dynamic component of blood pressure called pulse pressure. Pulse pressure is the difference in pressure between when the ventricles of the heart contract and when they relax. It can be felt as a throbbing beat in an artery, called a pulse.

When the ventricles contract, blood is pumped out of the left ventricle into the main artery leading away from the heart to the body, called the aorta. This creates the highest pressure that occurs in the aorta, called the systolic blood pressure.

The increased pressure and increased blood volume cause the aorta to stretch. Because the blood pressure in the aorta is higher than the pressure in more distant vessels, blood moves forward toward the body's tissues.
When the ventricles relax, blood stops flowing into the aorta and the pressure drops to its lowest level. This is called the diastolic blood pressure.
But blood continues to move forward in the circulation even when the ventricles are relaxed. Because the walls of the aorta and other elastic arteries bounce back, they maintain pressure on the blood moving through them.

Need to Know:
Recent study results suggest that individuals with large pulse pressures are at the greater risk for complications of high blood pressure, such as stroke or heart attack.

Nice To Know:
Most drugs that decrease blood pressure cause blood vessels to widen, making it easier for blood to pass through them, or cause the heart to beat less forcefully. But there's growing interest in factors that determine the pulse pressure, such as the arteries' ability to stretch or to store the blood ejected with each heartbeat. Less flexible arteries have been linked to high blood pressure, while some treatments that lower blood pressure also improve the arteries ability to store blood.

Why Is It Important To Control High Blood Pressure?
High blood pressure is a dangerous condition, and it should be treated appropriately. Over a period of time, once damage to the heart or other organs has begun, it is often irreversible. Uncontrolled high blood pressure damages the heart and other organs, accelerates hardening of the arteries and build-up of cholesterol-laden plaques on arterial walls, and can be lethal.
· If your systolic blood pressure is generally greater than 160 mm Hg, your risk of suffering stroke is four times greater than normal.
· If your diastolic blood pressure is generally greater than 95 mm Hg, your risk of developing coronary artery disease more than doubles.
· If your overall blood pressure is generally greater than 160/95, your risk of developing congestive heart failure is four times greater than normal.

Need to Know:
High blood pressure joins smoking and high cholesterol as one of the most important risk factors for coronary artery disease. High blood pressure is the most important risk factor for stroke.

High Blood Pressure And Your Heart
In people with high blood pressure, the heart has to work harder to keep up the increased pressure in the blood vessels. This puts a strain on the heart in the long term. It can affect the heart in a number of ways, including:
· Coronary heart disease, in which the arteries that feed the heart become narrow and clogged with fat and cholesterol deposits. People with coronary heart disease may experience angina, the chest pain or discomfort in the chest that happens when the heart doesn't receive enough oxygen, or a heart attack, in which part of the heart is deprived of oxygen and becomes damaged.
· Left ventricular hypertrophy, in which the wall of the major pumping chamber of the heart thickens as a result of the increased work by the heart. This can damage the normal functioning of the heart. People with left ventricular hypertrophy are at increased risk for stroke, heart attack, sudden death, and heart failure.
· Congestive heart failure, which occurs when the weakened heart cannot pump enough blood to meet the body's needs. Fluid may build up in the ankles, legs, lungs, and other tissues.

High Blood Pressure And Stroke
High blood pressure is one of the most important risk factors for stroke. People with high blood pressure are up to ten times more likely than people with normal blood pressure to have a stroke.

Like the heart, the brain depends on a constant supply of oxygenated blood. A stroke occurs when the brain's supply of oxygen and other nutrients is cut off. This can happen when the arteries leading to the brain become blocked (ischemic stroke) or when the artery wall tears (hemorrhagic stroke).

This "brain attack" can cause permanent or temporary damage. If the stoppage and damage is temporary, it is called a transient ischemic attack (TIA).

Need to Know:
High blood pressure, especially high diastolic pressure, increases the risk of all kinds of stroke.

Other Damage Caused By High Blood Pressure
The dangers of high blood pressure are not limited to heart diseases and stroke. High blood pressure can damage other organs and cause other problems, including:

· Kidneys - Almost one-third of all cases of kidney failure are caused by high blood pressure.
· Bones - High blood pressure causes more calcium to be excreted in the urine, leading to a loss of bone mineral density called osteoporosis. Postmenopausal women are especially affected and may be at greater risk for fractures and other problems.
· Legs and feet - In people with high blood pressure, impaired blood flow to the legs and feet may cause a condition called peripheral vascular disease. People with peripheral vascular disease often experience leg pain, numbness, loss of leg hair, open sores on the legs, feet, and toes, and difficulty walking.
· Eyes - High blood pressure may cause damage to blood vessels in the eyes, leading to a disease of the retina.
· The brain - In older people, high blood pressure may cause a loss of mental function and contribute to decreased short-term memory and attention, Alzheimer's disease, and dementia, although the reasons why are not clear.
· Sexual drive - High blood pressure is associated with sexual dysfunction in both women and men. In one study, women with high blood pressure experienced vaginal dryness and difficulty achieving sexual satisfaction. About 17 percent of men with high blood pressure experience some form of sexual dysfunction. Some medications used to treat hypertension can also impair sexual function.

Nice To Know:
Are you at risk for developing high blood pressure?
Anyone can develop high blood pressure. But experts have identified some characteristics that increase the risk. Some of these so-called "risk factors" cannot be changed, but some can. While risk factors don't necessarily cause high blood pressure, they can contribute to it or make it worse.

Your risk is greater if one or more of the following statements apply to you:

Risk factors you cannot change:
. You have a close relative with high blood pressure, especially a brother or sister.
. You are a male younger than 50 years of age.
. You are a postmenopausal woman.
. You are black.

Risk factors you can change or control:
. You are overweight.
. You do not exercise regularly.
. Your diet is high in sodium.
. You are a smoker.
. Your cholesterol levels are high.
. Your diet doesn't include enough calcium or potassium.
. You have more than two or three alcoholic drinks a day.
. You are under constant stress.
. You have diabetes.

Need to Know:
It is important to recognize your own personal risk factors. While you cannot change some risk factors like your family history or your age, you certainly can change or control other important risk factors like your smoking habits, your weight and diet amongst others, that will effectively lower your risk of developing high blood pressure.

What Causes High Blood Pressure?
In 90 to 95 percent of people with high blood pressure, doctors do not know what causes it. High blood pressure with an unknown cause is called essential, or primary, hypertension.
Sometimes, an underlying disease or other condition is found to be the cause of the high blood pressure. This type, called secondary hypertension, only occurs in 5 to 10 percent of people with hypertension.

High Blood Pressure With No Known Cause (Essential Hypertension)
Essential hypertension is the term used when no cause can be found for the high blood pressure. Most people with high blood pressure have essential hypertension.

Researchers do know that essential hypertension tends to cluster in families, so heredity is thought to play a strong role. For example, siblings of people with high blood pressure are more likely to have high blood pressure than the general population. Essential hypertension is more common in some racial and ethnic groups, which also suggests a genetic basis.

Family members may also share environment and lifestyle habits associated with an increased risk of essential hypertension.

High Blood Pressure For Which There Is A Cause (Secondary Hypertension)
While most people with high blood pressure cannot attribute it to a specific cause, the other 5 to 10 percent of people with high blood pressure have an underlying condition that causes it.
In a few cases, high blood pressure can be attributed to a specific cause. This form of high blood pressure is called secondary hypertension, because it is secondary to something else.

In these people, treating the underlying cause can often control the high blood pressure.

Causes of secondary hypertension include:
Renal (kidney) disorders, such as:
1. Renal vascular disease - A disease involving the kidneys' blood vessels
2. Renal parenchymal disease - A variety of diseases involving kidney tissue

Endocrine disorders, such as:
1. Hyperaldosteronism - A clinical syndrome caused by excessive secretion of aldosterone, a hormone that influences body sodium and potassium levels

1. Cushing's syndrome - A group of symptoms caused by high levels of the steroid hormone cortisol.
2. Adrenal gland tumors
3. Hyperthyroidism - A condition encompassing several specific diseases of the thyroid gland in which secretion of thyroid hormone is unusually increased.
4. Hyperparathyroidism - A condition caused by excessive secretion of parathyroid hormone, due to disease of the parathyroid glands or chronic low serum calcium levels. This hormone plays a most important role in controlling calcium levels in the body.

Neurological conditions, such as:
1. Increased pressure inside the space within the skull occupied by the brain
2. Lead poisoning - A sudden or ongoing intoxication with lead or its salts, which may cause stomach upset, constipation, abdominal pain, and/or neurological problems
3. Quadriplegia - The paralysis or loss of voluntary movement of all four limbs

Drugs and chemicals, including:
1. Oral contraceptives (birth control pills)
2. Corticosteroids
3. Appetite suppressants
4. Antidepressants
5. Nonsteroidal anti-inflammatory agents (such as Advil or Motrin)
6. Nasal decongestants
7. Cocaine

Miscellaneous causes, including:
1. Pregnancy - Hypertension can develop during pregnancy. If the high blood pressure is sudden and severe, the condition is called pre-eclampsia and can endanger both mother and child.
2. Coarctation of the aorta - Constriction or narrowing of the aorta, the large artery arising from the base of the left ventricle
3. Excessive licorice consumption - Licorice contains substances known to raise blood pressure, although the exact amount a person would have to consume to have an effect on blood pressure is not fully researched.

Need to Know:
Isolated systolic hypertension
Isolated systolic hypertension refers to a situation in which only the systolic blood pressure (the first number of the blood pressure measurement) is high, 140 mm Hg or greater, and the diastolic blood pressure (the second number) is normal or at the high end of normal (below 90 mm Hg).

Causes of isolated systolic hypertension include:
. Advancing age
. Abnormalities of heart valves
. Anemia - A condition in which the number of red blood cells in the blood is decreased.
. Thyrotoxicosis - A condition in which the body produces too much thyroid hormone.
. Paget's disease - A chronic disorder in which areas of skeleton are replaced by soft and enlarged bone.

Potential Causes Of High Blood Pressure
Researchers are studying conditions that may cause hypertension. The list of potential causes includes:

Genetic abnormalities of the renin-angiotensin-aldosterone system - Researchers are studying genes that control a group of hormones called the renin-angiotensin-aldosterone system (RAAS).

The RAAS is a critical player in blood pressure control. It regulates blood volume, blood vessel contraction, sodium and water balance, and the development of cells in the heart.

Abnormalities of this system, which can be genetic, may lead to hypertension by causing an increase in:
. Blood volume (by causing the kidneys to retain too much water and sodium), and/or
. Peripheral resistance (by causing blood vessels to narrow)
. Genetic abnormalities of the "fight or flight" system, called the sympathetic nervous system - . Excessive activity of the sympathetic nervous system can increase blood pressure by increasing heart rate, the force of the heart's contractions, and/or resistance to blood flow.
. Insulin resistance - Insulin is a hormone secreted by the pancreas that acts as the "key" that allows sugar and other nutrients to move from the blood into cells. Insulin resistance refers to a state in which cells are resistant to the effects of insulin. Insulin resistance in skeletal muscle cells causes them to take up less sugar from the blood, leading to high blood sugar levels and eventually, type 2 diabetes, which is linked to high blood pressure.
. Sodium retention in the urine - Usually, the kidneys respond to high blood pressure by excreting sodium in the urine. If this normal mechanism of regulating blood pressure is lost, persistent hypertension can result.
. Resetting of baroreceptors - Large blood vessels contain pressure detectors called baroreceptors, which signal the brain when blood pressure gets too high or too low. These baroreceptors may be "reset" so that higher blood pressures are required before the body recognizes increased blood pressure and acts to lower it.
. Arterial stiffening - Stiffening of the large arteries has been associated with all forms of hypertension. As a blood vessel loses its ability to stretch and to hold fluid, blood pressure increases.
. Blood vessel thickening - Stress, hormones, and genetic defects that cause smooth muscle cells in the walls of smaller arteries to constrict or grow are also being studied. These factors can cause smooth muscle cells in the arteries to increase in size and number, leading to thicker vessel walls and narrowing vessels.
. Deficiencies in vasodilators - A variety of substances in the body cause vessels to dilate, making it easier for blood to flow and reducing blood pressure. Deficiencies in some of these substances have been linked to hypertension.

Nice To Know:
Recent scientific research suggests that a problem of the inner lining of blood vessel walls, called the endothelium, may contribute to hypertension. Substances released from the endothelium can cause blood vessels to dilate or constrict. Some substances also promote or inhibit growth of the smooth muscle cells in the blood vessel wall.

Normally, the actions of these substances are held in balance. But in some people, the constriction chemicals may overpower the relaxation chemicals. Arteries narrow, and blood pressure goes up because it is more difficult for blood to circulate.

How is Blood Pressure Measured?
Blood pressure is measured in millimeters of mercury (mm Hg). A typical normal blood pressure is 120/80 mm Hg, or "120 over 80." The first number represents the pressure when the heart contracts and is called the systolic blood pressure. The second number represents the pressure when the heart relaxes and is called the diastolic blood pressure.

Blood pressure measurement is a painless and simple test. Blood pressure is one of the key identifiers of general health that will almost always be measured at the doctor's office. Reliable machines are available for you to measure your own blood pressure at home.

How To Information:
To help make sure your blood pressure measurement is accurate, avoid smoking and eating or drinking anything that contains caffeine for 30 minutes before the test. Rest for five minutes before the measurement is taken. Your health care provider will usually ask you to sit in a chair, with your bare arm comfortably supported at the level of your heart.

Blood Pressure Measurement In The Doctor's Office
Most people are familiar with having their blood pressure measured during routine visits to the doctor's office or other health care facility. But did you ever wonder exactly what your health care provider is doing? Here are the steps your health care provider should follow when taking your blood pressure measurement:

. Your health care provider will probably use a blood pressure cuff and stethoscope to measure your blood pressure. The blood pressure cuff, also called a sphygmomanometer, consists of a cuff with an inflatable bladder, a rubber hand bulb with a valve used to inflate and deflate the cuff, and a pressure gauge.
. First, the cuff is wrapped snugly around your upper arm. The cuff is then rapidly inflated until the pulse in the upper arm is no longer felt. At this point blood flow in the underlying blood vessel is cut off by pressure in the cuff. The health care provider will continue to inflate the cuff a bit beyond this point.
. Next, a stethoscope is placed over the brachial artery at the elbow and the cuff is slowly deflated, while the health care provider listens for sounds produced by turbulent blood flow in the artery.
. The health care provider listens through the stethoscope until he or she hears the heartbeats. . At this point, cuff pressure matches pressure in the artery, and blood flow resumes. This is the systolic blood pressure (SBP).
. The health care provider continues to slowly deflate the cuff until the sounds stop. This is the diastolic blood pressure (DBP).
. Experts recommend that two or more readings (separated by two minutes) be taken to determine an average blood pressure for the visit. If the first two readings differ by more than 5 mm Hg, additional readings should be obtained and averaged. Your doctor should tell you if your blood pressure should be measured again and/or if you should consider treatment for high blood pressure.

Measuring Your Own Blood Pressure
Stress, caffeine, smoking, pain, and other factors can cause blood pressure to rise temporarily. For some people, just the act of having their blood pressure taken in a doctor's office, clinic, or hospital can cause a rise in blood pressure. At other times, their blood pressure is normal. These people have what is called white coat hypertension.

Because so many different things can cause a temporary rise in blood pressure, your doctor may ask you to measure your own blood pressure at home. Various home monitors are available that simplify the process of measuring your own blood pressure.

Home monitors are reasonably accurate. However, some types of monitors (for example, finger monitors) have been associated with inaccurate blood pressure readings. Be sure to check your home monitor periodically for accuracy. When you visit your doctor, bring your home monitor and ask the person who takes your blood pressure measurement to compare the reading they obtain with a mercury sphygmomanometer to the reading on your home device

Keeping Track Of Blood Pressure On The Go
On-the-go, or ambulatory, blood pressure monitoring may be useful for some people. These include people who suffer from white coat hypertension, those who are not responding to blood pressure medication, or those with other complicating factors.
A variety of reliable, easy-to-use, and accurate ambulatory monitors are available commercially. These monitors can be worn over the shoulder or around the waist and typically record readings every 15 to 30 minutes, 24 hours per day.

Nice To Know:
Blood pressure values obtained with ambulatory monitors are 5 to 10 percent lower than those obtained by other means.

Is Your Blood Pressure Too High?
Most people with high blood pressure do not experience any symptoms, which is why regular blood pressure checks are so important.

High blood pressure can only be diagnosed with repeated blood pressure measurements. The best way to tell if you have high blood pressure is to have your blood pressure measured by a health professional.

Sometimes individuals with severe or chronic high blood pressure experience headache, dizziness, fatigue, or blurry vision. These are danger signs, and medical help should be sought immediately. People with lesser degrees of blood pressure elevation may experience sleep disturbances, emotional upset, or a dry mouth.

Although blood pressure varies from person to person, there are accepted guidelines for what is considered optimal, normal, and high. Since high blood pressure is associated with cardiovascular and other diseases and even death, it is critically important to identify and treat it early. You can use the following chart to help determine whether your blood pressure is too high.

This classification, which comes from the sixth Joint National Committee's report on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI), is referred to as the JNC VI Blood Pressure Classification System.
Blood Pressure Classification System.

YOUR BLOOD PRESSURE
If your systolic blood pressure readings are consistently greater than 140 mm Hg and/or your diastolic blood pressure readings are consistently greater than 90 mm Hg, your blood pressure is considered high.

When the systolic blood pressure and diastolic blood pressure fall into different categories, the higher category should apply. For example, a blood pressure of 165/94 mm Hg should be classified as stage 2 hypertension.
Although "optimal blood pressure" is defined as a blood pressure of less than 120/80 mm Hg, unusually low readings should also be evaluated.

Need to Know:
A single blood pressure reading may suggest high blood pressure, but your doctor should obtain a series of blood pressure readings. A variety of factors cause daily fluctuations in blood pressure, including:
. Time of day
. Hormone levels
. Drugs
. Pain or stress
. Certain diseases
. Cigarette smoking
. Drinking caffeine-containing products (such as coffee, tea, or cola)

Based on your initial readings, your doctor will let you know whether you should return for further blood pressure checks and/or treatment.

In short, a diagnosis of hypertension is not based on a single blood pressure reading. High blood pressure can only be diagnosed on the basis of multiple blood pressure readings.
After the initial screening, your doctor should take two or more readings during each of two or more office visits.

Any person 18 years or older who is not acutely ill (for example, with a flu or cold) or taking medication to control hypertension can be diagnosed with high blood pressure for a sustained systolic pressure of 140 mm Hg or greater or a diastolic pressure of 90 mm Hg or greater.

Need to Know:
If your blood pressure is in the normal range, you should have it rechecked in two years. Those with high-normal blood pressure should have it rechecked in one year.
But if your blood pressure reading is above normal, you need to return for one or more blood pressure visits within the next one to two months. Anyone with a systolic blood pressure of 180 mm Hg or more, or a diastolic blood pressure of 110 mm Hg or more, should receive care immediately, or within one week at most.

What Happens if Your Blood Pressure is High?
If your blood pressure readings suggest that you have high blood pressure, your doctor will conduct a thorough evaluation of your health status. In order to determine the best course of treatment for you, your doctor will look for answers to the following questions:

1- Is there an identifiable cause of the hypertension?
2- Are other risk factors for heart disease present?
3- Is there evidence of damage to other organs? If so, what is its extent?
4- Is there another condition that may influence the outcome or treatment?

Need to Know:
Although in most people no cause is found for the high blood pressure, the doctor must first rule out a possible cause. That's because identification and correction of a condition that may be causing the high blood pressure often leads to normal readings.

To evaluate your health status, your doctor will use these tools:

1- Personal Health History
A personal health history is one of the most important tools doctors use to determine the most appropriate treatment for you. Your doctor will ask a series of questions including:

Does anyone in your family have a history of:
. High blood pressure
. Coronary heart disease
. Diabetes
. Stroke
. High cholesterol levels
. Kidney disease
. Do you have any personal habits that could affect your blood pressure, such as smoking, illicit drug use, or a sedentary lifestyle?

1- What dietary factors could be affecting your blood pressure? These include sodium (e.g., table salt), saturated fats, alcohol, and caffeine (e.g., coffee, colas).
2- What prescription, over-the-counter medications (such as decongestants?

3- Have you ever been treated for high blood pressure before? What were the results and, and were there any adverse effects?

4 - Do you have a history of heart disease?
5- What recent changes in weight, physical activity, leisure-time activities, or other psychosocial and environmental factors (such as family situation or occupation) might be influencing your blood pressure?

Physical Examination

The physical examination can also help your doctor to determine the right treatment for you, and can help to rule out specific causes of hypertension that can be corrected. In addition to obtaining additional blood pressure readings, the doctor will look for possible involvement of other organs.

During the physical examination, the doctor will look for:
. Health indicators including blood pressure, heart rate, respiratory rate, body temperature, height, weight, and girth. Blood pressure readings may be obtained in both arms and in different positions (such as while lying down and standing).
. Evidence of damage to blood vessels in the eyes
. Abnormal sounds in blood vessels in neck that may occur with coronary artery disease, called carotid bruits
. Distended neck veins, which are sometimes seen with heart failure
. An enlarged thyroid gland, which may suggest an underlying thyroid condition
. Abnormalities in heart rate, rhythm, or size
. Abnormal heart sounds
. Abnormal crackling or wheezing sounds in the lungs, which may suggest heart failure
. Masses in the abdomen, called bruits
. Abnormal pulsations of the aorta
. Abnormal kidney size, which may suggest kidney disease
. Decreased or absent pulses in the extremities, which may indicate peripheral vascular disease
. Swelling in the lower leg due to accumulation of watery fluid in tissues, which may indicate heart failure or other conditions
. Changes in mental function, sensation, motor control, or reflexes

Routine Tests Your Doctor May Request
Your doctor will use information obtained from your personal health history and physical examination to determine which laboratory tests and imaging studies you should undergo. The following tests are routine:

Urinalysis, or analysis of the urine
Complete blood cell count, which determines the number of each major type of blood cell; involves drawing blood
A 12-lead electrocardiogram (ECG or EKG) that provides a record of the heart's electrical activity

Blood chemistry tests including:
. Potassium level
. Sodium level
. Creatinine level, which is a way to measure kidney function
. Fasting glucose level (level of blood sugar in fasting state)
. Total cholesterol level and triglyceride level
. High-density lipoprotein (HDL) cholesterol level analysis. This is sometimes called "good cholesterol."
. Low-density lipoprotein (LDL) cholesterol level analysis. This is sometimes called "bad cholesterol".

Other Tests Your Doctor May Request
Hypertension due to a known cause is not very common. But if information from your personal health history and physical examination suggest that there may be an underlying cause for your high blood pressure, your doctor may order additional tests. Other tests also may used to determine or confirm the presence of other risk factors for heart disease and damage to other organs.

Other tests your doctor may want you to have include:
. Creatinine clearance, a urine test to screen for kidney disease
. Fasting triglyceride level and low-density lipoprotein (LDL) cholesterol level
. Blood calcium level to screen for hyperparathyroidism
. Blood uric acid level to screen for gout
. Glycosylated hemoglobin to screen for diabetes mellitus
. Thyroid-stimulating hormone to screen for thyroid disease
. Chest x-ray to screen for signs of coarctation of the aorta
. Echocardiography to screen for evidence of heart failure
. Ultrasonography of arteries or measurement of ankle/arm index to screen for peripheral vascular disease

How is High Blood Pressure Treated?
Although high blood pressure can nearly always be brought down to safe levels, your doctor cannot do it alone. You need to become a partner in your own care.

What Are The Guidelines For Treating High Blood Pressure?
Treatment for high blood pressure consists of lifestyle modifications and drug therapy.
To help doctors identify appropriate treatment for high blood pressure, a group of experts has developed a system that establishes guidelines for treatment. These guidelines are based on the level of blood pressure, associated cardiovascular risk factors, and the presence or absence of damage to other organs and heart disease, referred to as target organ damage and clinical cardiovascular disease.

In this system, high blood pressure is classified by stages, depending on:
1- How high your blood pressure readings are, as well as your risk factors that may make you more likely to have high blood pressure
2- Whether there is any existing heart disease
3- Whether there is any damage to other organs

This classification, which comes from the sixth Joint National Committee's report on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI), is referred to as the JNC VI Risk Stratification System.

People in risk group A have either a normal blood pressure but in the upper normal limit, or high blood pressure (either stage 1, 2, or 3) without other risk factors, organ damage, or clinical cardiovascular disease.

Those with stage 1 hypertension can first undergo lifestyle modification with frequent blood pressure monitoring. If their target blood pressure is not achieved within one year, drug treatment should then be added.

Those with stage 2 or 3 hypertension are treated with medication
Most people with hypertension fall into risk group B. They may have a number of risk factors other than diabetes, but do not show evidence of organ damage or clinical cardiovascular disease. Depending on the blood pressure stage and number of risk factors, initial drug treatment may be needed. These individuals should also undergo lifestyle modification.

People in risk group C are most in need of prompt drug therapy. These include those with high or high-normal blood pressure who have clinical evidence of target organ damage or clinical cardiovascular disease and/or diabetes, with or without other risk factors. Lifestyle modification is also important in these

What You Can Do to Control Your Blood Pressure
Lifestyle changes play an important role in managing high blood pressure. Although permanent changes in lifestyle and diet are sometimes difficult to achieve, they may eliminate the need for drug treatment or allow reductions in the dosages of medications.

A recent study showed that well-motivated individuals with Stage 1 and 2 hypertension were able to adopt changes in diet and lifestyle that led to significant weight loss, reduced sodium and alcohol intake, and increased physical activity. These people significantly reduced their blood pressures.

Lifestyle changes carry other benefits, as well. They can keep high blood pressure from developing in the first place, reduce other cardiovascular risk factors, and improve your overall health.
Experts recommend the following lifestyle modifications for the prevention and management of hypertension:

Losing Weight Safely

Being overweight goes hand in hand with high blood pressure. Excess abdominal fat is also associated with high cholesterol levels, diabetes, and heart disease.

Fortunately, most people with high blood pressure can significantly reduce their blood pressure by losing as little as 10 pounds. Weight loss also reduces the risk of heart disease and enhances the effects of some medications used to treat high blood pressure.

Any overweight individual who has high blood pressure should take steps to reduce body weight. These measures include dietary changes and exercise. A nutritionist can also help you develop a healthful weight loss diet.

How To Information:
Here are some guidelines for losing weight and keeping it off:
1- Lose weight slowly. Plan to lose no more than two to four pounds a month.
2- Cut down on fatty foods. Eat a balanced diet that includes lots of fruits and vegetables.
3- Get more exercise. Exercise will help you to burn calories, and it will also help you to lose fat, not muscle.
4- Becoming Physically Active
5- Besides reducing the risk of high blood pressure and other cardiovascular disease, physical activity can enhance weight loss and general health. The best type of exercise for preventing and reducing high blood pressure is regular aerobic physical activity, which includes things like walking, cycling, swimming, jogging, aerobic dance classes, rowing, dancing, and skating - in short, anything that raises your heart rate for an extended period of time. Whatever activity you choose, make sure to start slowly and build up gradually.
6- People with high blood pressure can effectively lower their blood pressure with moderate physical activity (such as 30 to 45 minutes of brisk walking most days).

7- People with normal blood pressure can also benefit from exercise. Compared with people who are fit and physically active, sedentary people with normal blood pressure have a 20% to 50% greater chance of developing high blood pressure.

Need To Know:
Most individuals can safely increase their physical activity without an extensive medical evaluation. But those with cardiovascular disease or other serious medical problems may need a thorough evaluation and referral to a medically supervised exercise program. Talk to your doctor about what is recommended for you before starting to exercise.

Nice To Know:
Q. If I exercise vigorously, like jogging, won't that be dangerous because my heart rate will speed up?

A. It is true that your heart rate will speed up when you exercise, causing your blood pressure to rise temporarily. But normally your body compensates by causing blood vessels to relax. With regular exercise, your heart will pump blood more efficiently. However, you should always check with your doctor before exercising. Some individuals (such as those with heart disease) may need to take special precautions, including a thorough medical evaluation, before beginning an exercise program. The hearts of some individuals are also more susceptible to increased stress associated with exercising.

How To Information:
To make sure that you are not placing too much strain on your heart, you should monitor your heart rate by checking your heart rate. To determine your heart rate, use your index and third finger to find the pulse at your wrist or neck, count for six seconds, and add a zero. Since heart rates that are generally safe for people who are exercising vary with different factors (including age and state of health), you should ask your doctor what is a safe range for you.

How To Information:
. Walking is one of the simplest, cheapest, and easiest ways to increase your physical activity level. For most people, walking is a good starting point,
. Start by buying a comfortable, well-fitted pair of walking shoes.
. Take short walks whenever you can fit them in. That might mean walking to the post office at lunch, or taking the dog for a walk in the evening.

Later, aim for longer exercise sessions:
. Start by walking for at least 15 to 20 minutes several times a week.
. Gradually build up to at least 30 minutes, five times a week.

Need To Know:
Exercise is one of the best ways to enhance your overall health and decrease blood pressure. However, exercise also puts additional strain on your heart.

Here are some safety rules to follow when exercising:
1- Do not get out of breath. If you find it hard to hold a conversation while you are exercising, slow down.
2- If you have any symptoms such as chest pain or extreme shortness of breath, stop immediately and contact your doctor.
3- If you want to try more vigorous activity, check with your doctor first. He or she may first want you to take a stress test.
4- Do not engage in muscle-building types of exercise (e.g., weight lifting) without checking with your doctor first. These types of exercise may raise your blood pressure.

Limiting Salt In Your Diet
The role that sodium plays in hypertension is somewhat controversial. Sodium, found in table salt and processed foods, appears to affect blood pressure in some people while having little effect on others.

Some people can reduce their blood pressure simply by reducing the salt in their diet. These people are considered "salt sensitive," meaning that their blood pressure goes up when they eat more salt and goes down when they eat less salt.

limit your salt and increase your Potassium

People who are most likely to be salt sensitive include:
1- Older people
2- Black people
3- People with diabetes
4- People with high blood pressure can benefit from a moderately reduced sodium intake in several other ways, as well.

Cutting back on the salt in your diet may also:

1- Reduce the need for medications to treat high blood pressure
2 - Reduce potassium loss with diuretic treatment (blood pressure treatment that reduces blood volume)
3- Protect you from osteoporosis and kidney stones
4- Possibly reverse a condition known as left ventricular hypertrophy, the thickening of the muscle in the wall of the left ventricle that can occur with uncontrolled hypertension

Need To Know:
Hypertension experts recommend that dietary sodium intake be restricted to no more than 2400 milligrams, or one teaspoon, of sodium a day. This is about two-thirds of the amount of sodium that Americans normally consume per day, the bulk of which (75%) comes from processed foods.

How To Information:
You can reduce the sodium in your diet with a few simple steps:
1- Cut down on salt used at the table.
2- Taste food before adding salt.
3- Remove the salt shaker from the table.
4- Cut down on salt used when cooking.
5- Reduce the amount of salt added to half the amount suggested.
6- Replace salt with alternative flavorings like pepper, garlic, lemon juice, herbs, and spices.
7- Eat sensibly at restaurants.
8- If you eat at fast-food restaurants, ask for a nutritional analysis of the foods, so you can check the sodium content of different items.
9- In Chinese restaurants, ask for food without monosodium glutamate (MSG).
10- Check labels on food purchased at the grocery store.
11- Use labels to compare the amount of sodium in canned, frozen, and packaged foods.
12- Look for foods or seasonings that are labeled "low sodium" or "sodium free."
13- Whenever possible, start with fresh food that you can season yourself.
14- Getting Enough Potassium And Calcium In Your Diet
15- Potassium and calcium may also help to reduce your risk of developing high blood pressure, or lower your blood pressure if it is already high.

Potassium. Studies suggest that high potassium intake may protect against the development of high blood pressure and help people with high blood pressure control their blood pressure. On the other hand, blood pressure may increase if you don't get enough potassium in your diet.

The best sources of potassium are fresh fruits and vegetables, especially bananas, prunes, grapefruits, tomatoes, and potatoes. If you eat enough of these foods, it will be easy to get the recommended 3500 milligrams of potassium daily. A banana, for example, contains about 500 milligrams potassium, while a medium-sized potato contains more than 700 milligrams potassium.

Potassium is even more important if your doctor prescribes certain types of medications, called diuretics, which cause the body to lose potassium. If potassium levels become too low, heart rhythms may be disturbed.

Need To Know:
Because some medications (such as potassium-sparing diuretics) and medical conditions (such as kidney disease) are associated with increased potassium levels, you should check with your doctor before using any potassium-containing salt substitutes or potassium supplements.

Potassium levels that are too high are extremely dangerous and can be lethal.

Calcium. Not getting enough calcium in your diet may also increase your risk for high blood pressure. Although increasing your calcium intake may also help to lower blood pressure, this effect is small, so calcium supplements are not generally recommended to lower blood pressure.

Getting enough calcium in your diet is important for other reasons. High blood pressure increases the risk of osteoporosis by causing calcium loss through the urine. Calcium regulates smooth muscle tone in blood vessels, is important for general health, and may help prevent some gastrointestinal cancers.

Limiting Alcohol Intake
Alcohol abuse causes about 10 percent of high blood pressure cases. People who drink three or more alcoholic drinks a day risk hypertension, while binge-drinkers have even higher blood pressures. Alcohol abuse also increases the risk for stroke, liver disease, and other serious conditions. It can also reduce the effectiveness of medications used to treat high blood pressure.

Yet limited alcohol intake does not raise blood pressure and has even been shown to lower risk of cardiovascular disease. Experts recommend that alcohol intake be limited to no more than 1 oz of ethanol per day. This could include two 12-oz beers, two 5-oz glasses of wine, or one 2-oz shot of 100-proof whiskey.

Women and lighter-weight individuals should restrict their alcohol intake to half this amount. This is because women absorb more ethanol than men, and lighter individuals are more susceptible to the effects of alcohol than heavier people.

Need to Know:
If you have any concerns about your alcohol intake, you should consult your doctor. Sudden stopping of heavy drinking can cause problems (including high blood pressure).

Quitting The Tobacco Habit
Avoiding tobacco in any form - including cigarettes, pipes, chewing tobacco, and cigars - can help to improve anyone's health. Those who quit smoking usually experience beneficial cardiovascular effects over the course of one year.

Each time you smoke a cigarette, your blood pressure rises for a short time. This sudden increase in blood pressure appears to be temporary, much like the short-term increase in blood pressure associated with the intake of caffeine-containing products such as coffee, tea, and colas.

However, smokers in one study had blood pressures up to 10 points higher than nonsmokers. Cigarette smoking increases the risk for other cardiovascular disease and cancer, and may also interfere with the effects of medications used to treat high blood pressure.

Your doctor can help you stop smoking, should you decide to quit. There are a number of available products (e.g., nicotine patch, gum, medication) designed to help you quit smoking.

Managing Stress
Although stress can increase blood pressure, it is not considered a major cause of high blood pressure. A number of studies have not proven that relaxation therapies or biofeedback to significantly reduce blood pressure. But these techniques do have other benefits. They can help to reduce anxiety and give you a sense of well-being. They also can help you make other important lifestyle changes, such as changes in dietary and alcohol intake, or quitting smoking.

Here are some techniques that can help you manage stress:
. Think ahead about times you may be under increased stress. Plan ways to avoid the situation, if possible.
. If you feel tense, take a walk or go for a swim. Exercise is a wonderful natural tranquilizer.
. Get a massage. A massage is a wonderful opportunity to relax mind, body, and spirit.
. Breathe. When you are under stress, concentrate on drawing air deeply into your lungs and let your abdomen expand - not just your chest.
. Explore yoga, meditation, or other techniques for stress reduction.
. Practice complete relaxation for a short time every day. Sit comfortably and relax your muscles in turn - first your legs, then your arms, then your shoulders, then your body, neck, and face.
. Imagine a soothing scene, like an empty beach on a calm, warm day. Empty everything else from your mind.
. If you feel unable to cope, ask your doctor to recommend a mental health professional who can assist you in dealing with stress.

What Medications Are Used To Treat High Blood Pressure?
Although changes in lifestyle and diet are essential steps to take in controlling high blood pressure, many people also need to use medications to keep their blood pressure in control.

Drug treatment has been shown to protect against stroke, heart failure, coronary events such as a heart attack, progression of kidney failure, and progression to severe hypertension.

Medications that lower blood pressure are often referred to as antihypertensive drugs, antihypertensive agents, or just antihypertensives. Generally these drugs are classified by how they work.

Many medications are available for effective blood pressure control. Currently, more than 100 drug preparations are available, and the list is growing. They include:

Need to Know:
Drugs that help lower high blood pressure have various side effects. If you experience severe side effects from any drug, contact your doctor immediately. Your doctor will probably be able to find another agent to control your blood pressure.

Diuretics ("Water Pills")
Diuretics, commonly called "water pills," cause the body to excrete water and salt. Diuretics are often the first-choice drug in the treatment of essential hypertension, and have been shown to reduce the occurrence of stroke by 40 percent and hypertension-related heart attacks by 16 percent.

Diuretics are often prescribed for blacks and elderly individuals, who are considered salt-sensitive. They are the preferred treatment for people with heart failure or isolated systolic hypertension. Diuretics can be used alone or in combination with other medications.

How diuretics work
Thiazide diureticsare most commonly used to treat mild hypertension. Over a short period of time, thiazide diuretics reduce blood volume by causing the kidney to excrete more sodium.

Water follows the sodium. This, in turn, means that the heart pumps less blood each minute (cardiac output), which lowers blood pressure.
Over a longer period of time, thiazide diuretics cause the smooth muscle in arterial walls to relax. The blood vessels dilate, making it easier for blood to pass through them, which lowers blood pressure.

Potassium-sparing diuretics are used in people with mild-to-moderate high blood pressure. These agents work by blocking the actions of the chemical messenger aldosterone on the kidney, which leads to the excretion of sodium but the retention of potassium.

Loop diuretics are sometime used in people with impaired kidney function. Loop diuretics cause more urine to be excreted than thiazide diuretics, but are less effective at lowering blood pressure and can cause severe electrolyte imbalances.

Nice To Know:
In general, diuretics are most effective in people with mild-to-moderate high blood pressure but normal kidney function.

What are the adverse effects of diuretics?
Although diuretics effectively reduce cardiovascular disease and death, they do have some drawbacks, including:
. Decreased (e.g., thiazides) or elevated (e.g., potassium-sparing) levels of potassium
. Elevated levels of blood sugar
. Elevated cholesterol levels of cholesterol
. Elevated levels of lipids
. Elevated levels of uric acid
. Occasional sexual dysfunction

Fortunately, when prescribed at low doses with careful electrolyte monitoring, these undesirable effects can usually be minimized.

Beta-Adrenergic Blocking Agents (Beta-Blockers)
Beta-adrenergic blocking agents, or beta-blockers, are frequently used to start treatment of hypertension. Beta-blockers lessen the heart's workload by decreasing the strength and frequency of heartbeats, slowing certain metabolic processes, and reducing blood pressure.

How do beta-blockers work?
These drugs work by blocking beta-receptors. Receptors are specialized sites at the nerve endings that are sensitive to certain chemical messengers in the body. These chemical messengers attach to the receptor sites and cause certain reactions.

Normally, the chemical messengers norepinephrine and epinephrine, commonly known as adrenaline, bind to these beta-receptors. These act to increase heart rate and make the heart pump harder, and also affect the lungs, kidneys, and blood vessels.

Beta-blockers are medications that reduce blood pressure by binding to the same site where these chemical messengers normally bind, much like someone taking your designated parking space. If the chemical messengers are unable to bind to the receptor site, they cannot exert their blood pressure-increasing effects, and so the blood pressure drops.

Beta-blockers:
. Slow the heart rate
. Reduce the strength of the heart's contractions, directly causing blood pressure to drop
. Can also indirectly lower blood pressure by slowing the kidney's production of a protein called renin. Renin normally causes the release of a powerful blood vessel constrictor called angiotensin II, which makes it harder for blood to flow through the arteries (thus raising blood pressure) and also causes secretion of hormones that cause water retention (which increases the amount of fluid in the blood).

What are the adverse effects of beta-blockers?
Beta-blockers are effective and useful drugs in the treatment of high blood pressure. However, they might not be right for everybody. Two of the hormones that beta-blockers interfere with - norepinephrine and adrenaline - also bind to beta-receptors in other regions of the body. In the lungs, these hormones cause smooth muscle in the walls of lung airways to relax, opening the airway and making it easier to breathe.

Beta-blockers interfere with this airway relaxation, instead causing the airways to narrow. This phenomenon, known as bronchoconstriction, can be particularly problematic for people with asthma or chronic obstructive pulmonary disease.

If you suffer from asthma or COPD, your doctor may prescribe a cardioselective beta-blocker. Cardioselective beta-blockers decrease blood pressure by confining their actions to the heart and kidneys, and do not block beta-receptors in lung airways.

There are also several combined alpha- and beta-blocker agents available to treat high blood pressure. These agents block alpha-receptors, which influence blood vessel constriction, as well as both types of beta-receptors.

Nice To Know:
In addition to treating high blood pressure, beta-blockers are used to treat other cardiac conditions, including angina associated with coronary heart disease and abnormalities of the heart rhythm.

Although beta-blockers are useful for controlling blood pressure in many people, they tend to be less effective than thiazide diuretics in older people and blacks. In addition, some people experience:
. Fatigue
. Depression
. Impotence
. High blood sugar level, or hyperglycemia
. Undesirable changes in blood fats
. Increased airway resistance (non-cardioselective beta-blockers)

If you are taking beta-blockers, your doctor should monitor you closely for signs of:
. Low blood pressure
. An abnormally low heart rate
. Worsening heart failure
. Increases in heart rate or blood pressure with sudden discontinuation of treatment

Need to Know:
Beta-blockers can have serious side effects. But careful monitoring and patient selection can reduce these risks. In fact, studies have shown that beta-blockers effectively reduce cardiovascular disease and death.

Like diuretics, beta-blockers are considered an appropriate initial drug choice for people with uncomplicated high blood pressure. They are also particularly useful in people who have previously suffered a heart attack.

Calcium Channel Blockers
Calcium channel blockers help lower blood pressure by relaxing blood vessels and reducing blood flow. They are effective in people with essential hypertension and have few side effects, but should not be used in people with heart failure or disturbances in the electrical conduction system of the heart.

How calcium channel blockers work
Calcium channel blockers cause blood vessels to relax, which makes it easier for blood to flow and lessens blood pressure. Some calcium channel blockers also slow the heart rate and reduce the strength of the heart's pumping action, causing blood pressure to fall.

Calcium ions are needed for muscles to contract. Calcium channel blockers inhibit the entry of calcium ions into the heart muscle and smooth muscle of blood vessels walls, reducing the force of heart muscle contraction and causing blood vessels to dilate.

There are four main types of calcium channel blockers:
1. Dihydropyridines (such as felodipine-type)
2. Phenylalkylamines (such as verapamil-type)
3. Benzothiazepines (such as diltiazem-type)
4. Tetralol (T-channel blocker)

Calcium channel blockers have different chemical structures, which means that the different types of calcium channel blockers affect the cardiovascular system differently. For example, all calcium channel blockers dilate arteries, but some dilate arteries in certain parts of the body to a greater degree than others.

Some types of calcium channel blockers slow heart rate more than others do. These differences reflect the different types of calcium channels, located in membranes of cells, that these agents block.

Long-acting dihydropyridine calcium channel blockers are particularly useful in the treatment of isolated systolic hypertension.

Adverse effects of calcium channel blockers
Calcium channel blockers can have some serious adverse effects on the cardiovascular system, including:
. Hypotension (low blood pressure)
. Disturbances in the heart rhythm
. Heart failure

Calcium channel blockers are not appropriate drug therapy for people with these heart conditions. Your physician should also obtain a record of the electrical activity of your heart (electrocardiogram or EKG) before prescribing a calcium channel blocker. The EKG is used to screen for certain heart disturbances.

These risks can be minimized with careful monitoring, patient selection, and use of long-acting medications.

Nice To Know:
Some controversy surrounded the use of one type of immediate-release (short-acting) calcium channel blocker after a study showed that the drug increased the number of deaths in people with heart disease. But this applied only to immediate-release drug formulations.

Longer-acting (sustained-release) preparations are current, popular means of treating high blood pressure as well as chest pain.

Other side effects of calcium channel blockers include:
. Flushing of the face
. Headache
. Dizziness
. Mild edema (swelling due to watery fluid outside of blood vessels)
. Constipation

The relatively low incidence of other side effects is an appealing feature. Your doctor can help you to decide whether calcium channel blockers represent a good treatment choice for you.

Angiotensin Converting-Enzyme (ACE) Inhibitors
Angiotensin-converting enzyme (ACE) inhibitors have been used successfully in people with all types of high blood pressure. ACE inhibitors have gained popularity in recent years. In addition to being used in the treatment of mild-to-moderate high blood pressure, they are also used in the treatment of heart failure, heart attack, and kidney disease due to diabetes.
ACE inhibitors can provide safe and effective blood pressure control for many people.

Your doctor may prescribe ACE inhibitors if you have:
. Heart failure
. A history of heart attack
. Type 1 diabetes with protein in the urine

Nice To Know:
ACE inhibitors are effective when administered alone. But they are often used in combination with a thiazide diuretic or beta-blocker

How ACE inhibitors work
ACE inhibitors interfere with the renin-angiotensin aldosterone system (RAAS). The RAAS regulates blood volume, blood vessel contraction, sodium and water balance, and the development of cells in the heart.

Angiotensin-converting enzyme (ACE) is a protein that converts the inactive hormone angiotensin into the active hormone angiotensin II. Angiotensin II increases blood pressure because it:
1- Causes blood vessels to narrow
2- Stimulates the release of a hormone called aldosterone, which causes the kidneys to retain sodium
3- Stimulates the release of a hormone called antidiuretic hormone, which causes the kidneys to retain water
4- Increases blood volume and cardiac output increase the kidneys retain more sodium and water

ACE inhibitors block the conversion of the inactive angiotensin I to active angiotensin II. With less angiotensin II circulating in the body, blood pressure drops because:
. Blood vessels relax
. Blood volume and cardiac output lessen because the kidneys retain less sodium and water

ACE also slows the breakdown of a substance produced by the inner lining of blood vessels, called bradykinin. Bradykinin causes blood vessels to dilate, and causes the release of two other substances that also make blood vessels dilate: nitric oxide and prostacyclin.

Because ACE inhibitors slow the breakdown of bradykinin, they could raise the relative levels of all three of these blood-vessel-relaxing substances.

Large studies have shown that ACE inhibitors:
1- Effectively lower blood pressure in individuals with high blood pressure
2- Improve the function of the inner lining of blood vessels, or endothelium
3- Reduce the frequency of future heart attacks in people with heart disease
4- Reduce death in individuals with a history of left ventricular dysfunction, heart failure, or heart attack
5- Slow the progressive loss of kidney function in individuals with diabetic nephropathy
6- Reduce the risk of stroke and heart disease in people with high blood pressure and diabetes.

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Adverse effects of ACE inhibitors
Like any drug, ACE inhibitors can also have side effects. The most common side effect of these drugs is a dry cough, but it is not permanent. This cough, as well as occasional spasms of lung airways and an allergic skin reaction called angioedema, has been attributed partly to the activation of bradykinin that happens when ACE is blocked.

Other reported side effects of ACE inhibitors include:
. Headache
. Dizziness
. Fatigue
. High potassium levels
. Rarely, a reduction in the number of white blood cells
. 10 percent of people treated with one type of ACE inhibitor, captopril, experienced a skin rash that was not permanent

Although ACE inhibitors can help individuals with some types of kidney disease, they should not be used in those with bilateral renalartery stenosis (narrowing of the arteries that supply blood to both kidneys).

Need To Know:

Angiotensin II Receptor blockers

People who develop a nagging cough with ACE inhibitors may be better off using a different, but related, medication. Angiotensin II receptor blockers are a relatively new class of high blood pressure medication.

Like ACE inhibitors, angiotensin II receptor blockers interfere with the vasoconstricting hormone angiotensin II. However, these drugs only work at specific sites and do not affect bradykinin, which is thought to contribute to the "ACE inhibitor cough."

Results from clinical trials suggest that angiotensin II blockers are about as effective as ACE inhibitors. Side effects of angiotensin II blockers include elevated potassium levels and rarely, an allergic skin disease called angioedema. Angiotensin II blockers are generally considered safe and appropriate for the treatment of high blood pressure, and, possibly, heart failure.

Vasodilators
Vasodilators widen arteries and veins, making it easier for the blood to pass through them. Your doctor may prescribe a vasodilator in combination with a diuretic or a beta-blocker. These drugs generally should not be used in people who have angina or who have had a heart attack.

How vasodilators work
Two of the most commonly prescribed vasodilators are prazosin hydrochloride and terazosin. Both of these medications work by dilating both arteries and veins. Prazosin is often used along with a diuretic or beta-blocker, but can also be used alone. Terazosin needs to be taken less frequently than prazosin, since its effects last for a longer time.

Prazosin works by binding to receptors than control blood vessel constriction, called alpha 1 receptors. The chemicals that would normally cause blood vessels to constrict can no longer bind to these sites, and both arteries and veins dilate.

Adverse effects of vasodilators
Vasodilators can have some side effects including:
. Headache
. Drowsiness
. Palpitations (the sensation of the heart beating rapidly, slowly, irregularly, or forcefully).
. Dizziness and/or occasional fainting upon standing, due to change in blood pressure

Examples Of Antihypertensive Agents*
*Representative examples from each class but not all-inclusive listing. (G) = available in generic form.

Antihypertensive Class
How they work

Examples: trade name (drug) Diuretics , Thiazides

Short-term effects: Cause the body to excrete water and salt. Less fluid remains in the blood, and cardiac output goes down.

Long-term effects: relaxation of smooth muscle in vessel walls, causing a decrease in PR.

K+-sparing diuretics
Increased renal (kidney) sodium excretion and potassium retention

Thiazides and related
. Hydrodiuril® (hydrochlorothiazide)(G)
. Potassium-sparing:
. Aldactone® (spironolactone)(G)

Loop diuretic
. Lasix® (furosemide)(G)

Beta-adrenergic receptor antagonists
(beta-blockers)

Direct actions: Reduces heart rate and the force of heart's contractions, leading to reduced cardiac output

Indirect actions: Reduced TR and blood volume by inhibiting renin secretion, which, in turn, lowers available levels of angiotensin II

1. Lopressor® (metoprolol tartrate); G
2. Inderal® (propranolol HCL)(G)
3. Tenormin® (atenolol)(G)
4. Combined alpha-beta-blockers:
5. Coreg® (carvedilol)
6. Normodyne® (labetolol HCL)(G)

Calcium channel antagonists
(calcium channel blockers)

Causes blood vessels to relax, making it easier for blood to flow; some calcium blockers slow heart rate and reduce the force of the heart's contractions

1. Procardia SL® (nifedipine)
2. Norvasc® (amlodipine besylate)
3. Cardizem SR® (diltiazem HCL)

Angiotensin-converting enzyme (ACE) inhibitors
Prevents conversion of angiotensin I to the vasoconstrictor angiotensin II. Lower levels of angiotensin II mean that blood vessels don't constrict as much, and blood flows more easily. Also thought to decrease cardiac output by decreasing levels of hormones (aldosterone and antidiuretic hormone).

1. Capoten® (captopril)(G)
2. Vasotec® (enalapril)
3. Accupril® (quinapril HCL)
4. Monopril® (fosinopril sodium)
5. Prinivil®, Zestril® (lisinopril) lisinopril

Angiotensin II receptor blockers
Prevents the vasoconstrictor angiotensin II from binding to certain receptors. Blood vessels don't constrict as much, and blood flows more easily.
1. Cozaar® (losartan potassium)
2. Diovan® (valsartan)
3. Avapro® (irbesartan)

Alpha-adrenergic receptor antagonists
(vasodilators)

Prevents messenger chemicals from binding to certain receptors (alpha type 1), which causes blood vessels to dilate and allows blood to flow more easily.

1. Hytrin® (terazosin HCL)
2. Minipress® (prazosin HCL)(G)

What Medications Are Right For You?
You will have to work with your doctor to figure out exactly what medication or medications are right for you, and what dosages control your blood pressure best.

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What Your Doctor Will Consider When Choosing Your Medication
Not every medication is right for everyone. When choosing the best medication for you to start taking, your doctor will consider:

. Your age
. Your race or ethnic background
. The severity of your high blood pressure
. If you have any other chronic diseases such as diabetes or heart failure
. If you are taking any other medications and remedies, including prescribed or over-the-counter drugs and herbal remedies

For example, diuretics and beta-blockers are often the first drugs used to treat high blood pressure. But a person with both high blood pressure and type 1 diabetes might fare better on an ACE inhibitor.

Some groups of people respond better to one type of drugs than to another. For example, older people and black people do not respond to beta-blockers as well as they do to diuretics.

Need To Know:
Other medications or remedies, including over-the-counter drugs and herbal remedies, may react with some types of blood pressure medication. In order to select the right medication for you, your doctor must know about any other medications or remedies you are taking.

How To Information:
What you should consider when choosing your medication
You should also have some input into choosing the right medication. Some things you might want to consider include:

. How often will you have to take the medication? Some drugs control blood pressure over a longer period, which means that you have to take your medication less often. These drugs may also provide smoother blood pressure control.
. How much does the medication cost? Older drugs are more likely to be available in less expensive, generic forms.
. How will the medication impact your day-to-day life? Can you live with the drug's side effects? Sometimes side effects can be decreased (or stopped) by reducing the drug dosage. In other cases, you doctor may recommend treatment with another agent.

What If The Medication Doesn't Lower Your Blood Pressure?
After selecting the medication to begin your treatment for high blood pressure, your doctor will advise you to start taking the lowest dosage possible. This is intended to avoid side effects as well as a fall in blood pressure that happens too rapidly. If your blood pressure remains uncontrolled after one or two months of therapy, your doctor will adjust the dose upwards.
If the full dose of the drug does not effectively control your blood pressure, your doctor will:

· Add another type of drug
· Switch to another type of drug

Adding a second type of drug can be useful if you are not having problems with the first drug. But if you are experiencing troublesome side effects, or if the first drug isn't lowering your blood pressure, your doctor is likely to recommend that you switch to another type of drug.

If your blood pressure is still not controlled after these changes, additional medications can be added. There are a variety of mixed-class medications that can reduce the number of pills you need to take each day.

If your blood pressure is still not adequately controlled, your doctor may refer you to a cardiologist with specific expertise in treating high blood pressure.

Nice To Know:

Q. If I take medication for my high blood pressure, and the pressure falls to normal, why do I have to keep taking the medication?

A. In some cases, high blood pressure is caused by another condition. This type of hypertension is referred to as secondary hypertension. Treating the underlying condition can sometimes cure secondary hypertension.
But 90 to 95 percent of people with high blood pressure have essential hypertension, for which there is no single identifiable cause. So if you stop taking your medication after your blood pressure falls to normal levels, it's likely that your blood pressure will increase again. As smooth, persistent control of blood pressure is a goal of treating hypertension, discontinuing your medication would be undesirable.

Also, some medications (for example, beta-blockers) can cause sudden increases in heart rate and blood pressure if you suddenly stop taking them. Therefore, you should never discontinue taking your medication on your own. This should be a decision made in consultation with your doctor.

How To Information:

How to get the most out of your medications
No matter what type of drug your doctor selects for you, there are some general rules to follow in order to get the most benefit from your medication:

. Keep taking the medication every day, even if your blood pressure begins to come down or if you feel fine.
. Make sure you know how and when you should take the medication (for example, with or without food).
. Do not adjust the amount of medication you take each day, either upwards or downwards. . Your doctor is the only person who should adjust your dosage of blood pressure medication.
. Keep track of any side effects that you experience and report them to your doctor.

. Find out what side effects are serious enough to warrant immediate medical attention.
. Make a note on your calendar to refill the prescription before it runs out.
. Make sure you have enough pills to take you when you travel.

Need To Know:
Remember that high blood pressure usually causes no symptoms, but it stays with you, inflicting damage on key organs if left uncontrolled.

Living With High Blood Pressure
It is estimated that more than 50 million Americans have high blood pressure, and most of them are unaware that they have it. Almost 75 percent of people with high blood pressure do not control their blood pressure to below the "danger zone" of 140/90 mm Hg.

But if your doctor tells you your blood pressure is high, remember that you can control it and live a normal life. In many people, high blood pressure can be eliminated with simple changes in lifestyle and diet. These changes can improve your blood pressure and enhance your overall health.

Once recognized, high blood pressure can be effectively controlled with appropriate measures. In partnership with your doctor, you can control your blood pressure. There are specific things each of you should do to help you to achieve your target blood pressure:

What you should do:
. Have your blood pressure checked regularly.
. Ask any questions you have about your blood pressure and treatment (try making a list before you next see your doctor).
. Keep all appointments and have your pressure measured as often as the doctor suggests.
. Follow your doctor's advice about changes in diet and lifestyle that can help to control your blood pressure.
. Be sure to tell your doctor about all medications (prescriptions, over-the-counter drugs, herbal remedies) you are currently taking. This information is important as it may influence the type and dose of medication your doctor prescribes.
. If the doctor prescribes medications, take them every day, on time, even if you feel fine.

. Never adjust or discontinue your medication without consulting a doctor, even if your blood pressure seems to be getting lower.
. Ask you doctor about potential side effects and which, if any, may require prompt immediate medical attention.
. Make a note of any side effects associated with your medications and report them to your doctor.
. Keep in touch with your doctor

What your doctor should do:
· Tell you the systolic and diastolic blood pressure readings and explain what they mean.
· Answer your questions and explain what is going on in simple, understandable terms.
· Tell you how often you should have your blood pressure rechecked.
· Tell you about lifestyle and dietary changes that you should try, and refer you to a nutritionist or other expert if you'd like more help.
· Ask you questions about your medical history and use of medications (prescribed and over-the-counter) or herbal remedies to determine what type of medication, if necessary, is right for you.
· Explain how any medications work and describe any side effects that may occur.
. Tell you about any conditions for which you should receive prompt medical attention, including side effects, adverse reactions of your blood pressure medications with other medications, and complications related to your blood pressure.
· Monitor you for side effects, and lower the dosage of your medication or switch you to a different type of medication if necessary.

Putting It All Together
. High blood pressure, or hypertension, refers to increased pressure or tension that the circulating blood exerts on the walls of the blood vessels
. Although blood inside the veins is under some pressure, the term hypertension is usually used to mean increased pressure in arteries.
. Blood pressure is determined by the heart rate, blood volume, how vigorously heart pumps, and resistance in blood vessels.
. Increases in heart rate, blood volume, how vigorously the heart pumps, or resistance in blood vessels may increase blood pressure.

. Hypertension occurs when the body fails to make appropriate adjustments for these changes.
. In the great majority of cases, a single specific cause of high blood pressure cannot be identified.

. High blood pressure with no known cause is called essential hypertension.
. High blood pressure rarely causes symptoms. It can only be detected with repeated blood pressure measurements obtained by a trained health care professional.
. Treatment of hypertension is based on the how high the blood pressure is, the presence or absence of other cardiovascular disease risk factors, and the presence or absence of damage to organs caused by the high blood pressure
. There are many simple lifestyle and dietary changes that can be made to help reduce blood pressure and reduce the need for medication.
. If necessary, there are a large number of safe and effective medications that can be prescribed to reduce and control high blood pressure.
. Even if your doctor prescribes medication for high blood pressure, you should also make lifestyle and dietary changes to control your blood pressure.
. Properly treated, high blood pressure should not interfere with daily living.
. Failure to control high blood pressure can lead to serious health problems, even death.