Hypertension Program Overview

Everyone knows that high blood pressure is bad, but most people have only a hazy idea as to why, and what the term really means. In fact, all of us have high blood pressure some of the time, and we wouldn't be able to function if we didn't. High blood pressure is only of concern when it persists for long periods of time, and its adverse effects actually take many years to develop. It's very common: according to official government figures it affects 50 million people in the United States. The other name for it is hypertension, a word that often causes confusion. People who have high blood pressure are not particularly "hyper" or tense, in the usual sense of the word. The term simply refers to the increased tension or pressure in the arteries.

The arteries are the elastic tubes that carry blood from the heart to the tissues. They are configured like a tree: the central trunk, or aorta, leaves the heart and then branches repeatedly. The smallest branches, which are visible only under a microscope, are called arterioles. They have muscle cells in their walls so that they can constrict and dilate, and hence direct the flow of blood to where it is most needed. The arterioles branch into even finer vessels, called capillaries, which form a delicate mesh that supplies the tissues with oxygen and other nutrients. For the blood to be able to circulate properly, a certain level of pressure is needed to force it through the arterioles and capillaries.

It's important to realize that blood pressure is continually varying in order to meet the ever-changing needs of our bodies. Blood pressure is normally regulated very tightly by the brain. When we're asleep, and our bodies are at rest, we consume less oxygen than when we're awake and active, and so the brain lets the pressure fall to a lower level. At the other extreme, when we're exercising, our muscles need a greater supply of blood to keep them going, and the pressure goes up.

How is Hypertension Diagnosed?

You probably recognize the numbers 120/80 as a normal blood pressure. But why two numbers? The explanation is quite simple. Your heart beats about 70 times a minute, and with each beat blood is pumped into the arteries. As this happens, the pressure inside the arteries goes up, until the end of that heartbeat. The peak level of pressure is called the systolic pressure. Then the heart relaxes, and begins filling with blood for the next beat, and the pressure in the arteries starts to fall and reaches a minimum level just before the next heartbeat, which is the diastolic pressure. So the number 120 refers to the systolic pressure, and 80 to the diastolic pressure. Each heartbeat produces a slightly different pressure, but usually the two numbers go up and down together.

The blood pressure is expressed as millimeters of mercury, usually abbreviated as mm Hg (Hg is the shortened version of the Latin name for mercury). The reasons for using mm Hg are both historical and practical. The pressure gauge used by doctors to measure blood pressure is called a sphygmomanometer, which has a column of mercury, the height of which is recorded in millimeters, and is a measure of the pressure inside the cuff.

 

Which Doctors Treat Hypertension?

Although it is so common, hypertension has not traditionally been treated by specialists, but by a variety of physicians, including family practitioners, internists, cardiologists, and nephrologists. This works fine for many patients, but others benefit from more specialized care. Some patients have rare (but curable) causes of hypertension that often go undiagnosed for many years, and others just can’t seem to find the right mix of medicines to keep their blood pressure under control. A recent development has been the recognition of Hypertension specialists whose primary focus is on diagnosing and treating all forms of hypertension and its complications.

 

How is blood pressure measured?

The traditional method of measuring blood pressure is with a sphygmomanometer and a stethoscope. The way it works is as follows: the cuff that is wrapped around your upper arm contains a rubber bag, which can be pumped up with air by squeezing a rubber bulb. The bag is also connected via a tube to the column of mercury, which measures the air pressure in the bag. To take a reading of the blood pressure, the cuff is pumped up to a pressure of about 200 mm Hg. This is nearly always higher than the systolic pressure, so that it completely shuts off the circulation of blood in the arm. Then the valve on the rubber bulb is opened a little, and the air in the bag allowed to leak out, and gradually lower the pressure in the cuff. While this is happening the person taking the pressure listens with a stethoscope placed on the elbow crease just below the cuff. When the cuff pressure is greater than the systolic pressure, there's no flow of blood and nothing to hear. But as the pressure is reduced, it gets to a point at which the systolic pressure in the artery is higher than the cuff pressure, so the artery starts to open, and blood to flow. Each spurt of blood makes a whooshing sound, which can be heard with the stethoscope. As the cuff pressure is reduced further the sounds get louder and last longer, but as the cuff pressure approaches the diastolic pressure they start to fade away. The point at which they finally disappear is the diastolic pressure. It may seem puzzling why the sounds come and go in this way, but when the flow of blood in the artery is not interrupted by the occlusion produced by the cuff, it's quite smooth, and makes no noise. What we hear when the cuff pressure is between systolic and diastolic pressure is partly the sound of the artery opening and closing, and partly the sound of turbulent flow.

In practice, there are other ways of measuring blood pressure that provide more information than the traditional stethosocope method. These are 24 hour ambulatory monitoring and home or self monitoring.

 

Why is high blood pressure so bad?

Everyone has high blood pressure some of the time, and it only causes a problem when it stays high for long periods. Even then, there are many people who live normal lives with high blood pressure and never know it. Unfortunately, not all are so lucky. The reason that doctors are concerned about high blood pressure is that it increases the risk of a number of serious events, chiefly strokes and heart attacks. Even if these do occur, however, it may be only after ten or twenty years of the pressure being high.

The damage caused by high blood pressure is of three general sorts. The first is the one everyone thinks of - bursting a blood vessel. While this is dramatic and disastrous when it happens, it's actually the least of the three problems. It occurs most frequently in the blood vessels of the brain, where the smaller arteries may develop a weak spot, called an aneurysm. This is an area where the wall is thinner than normal and a bulge develops. When there is a sudden surge of pressure the aneurysm may burst, resulting in bleeding into the tissues of the brain, and hence a stroke.

The second adverse consequence of high blood pressure is that it accelerates the deposition of cholesterol plaque (atheroma) in the arteries. This problem, too, takes many years to develop, and it is very difficult to detect until it causes a major blockage. It affects mainly the larger arteries, but deposition is not uniform. It accumulates most where an artery divides into two smaller branches. The blood flow is normally smooth in the arteries, but where they divide it becomes turbulent, and this turbulence is thought to damage the delicate lining of the arteries. Wherever this damage occurs, cholesterol deposits are more likely to accumulate. The most important sites to be affected are the heart, where atheroma causes angina and heart attacks; the brain, where it causes strokes; the kidneys, where it causes renal failure (and can also make the blood pressure go even higher); and the legs, where it causes a condition known as intermittent claudication, which means pain during walking.

Third, high blood pressure puts a strain on the heart: Because it has to work harder than normal the muscle enlarges, just as any other muscle does when it is used excessively. In people with high blood pressure the volume of the heart doesn't change very much, but the thickness of the muscle increases. Thickening of the heart muscle is bad because the muscle outgrows its blood supply, rendering it more susceptible to the effects of atheroma narrowing the coronary arteries that supply the heart.

 

Are there different types of high blood pressure?

Yes. High blood pressure can be classified in two ways, one according to how severe it is (mainly a question of how high the blood pressure is) and the other according to what's causing it. About 95 percent of people with high blood pressure have what is known as essential hypertension, which is really a fancy way of saying that it just happens, and we don't know why. The other 5 percent of cases have secondary hypertension, where there is an identifiable and usually correctable cause. The commonest of these is renovascular hypertension, where there is narrowing of the artery to one or both kidneys. Other less common causes of secondary hypertension are small tumors of the adrenal glands that secrete blood pressure-raising chemicals (hormones) into the bloodstream.

The term essential hypertension is not a very specific one. It is thought that hypertension is the end result of a number of different factors that make the blood pressure go up, and it is probable that different mechanisms are important in different individuals. This may explain why a particular type of treatment may work very well in one person, but not at all in another.

Classification of hypertension by its severity is somewhat arbitrary because there's no precise level of pressure above which it suddenly becomes dangerous. For no particularly good reason, blood pressure has traditionally been classified according to the height of the diastolic pressure, although the systolic pressure is probably more important in determining the level of risk. Someone whose diastolic pressure runs between 90 and 95 mm Hg may be regarded as having borderline hypertension, and when it's between 95 and 110 mm Hg it's moderate, and at any higher levels it's severe. The most dangerous type is called malignant hypertension, which is regarded as an acute emergency requiring immediate treatment in a hospital. Whatever the underlying cause, when the blood pressure reaches a certain level for a sufficient length of time it sets off a vicious cycle of damage to the heart, brain, and kidneys, resulting in further elevation of the pressure. Not surprisingly, if untreated, malignant hypertension can be rapidly fatal. Because more people are treated nowadays than before, malignant hypertension is not common, and is mainly seen in people who have not had access to medical care.

White coat (or office) hypertension is a term used to describe people whose blood pressure is only high in a doctor's office.

Systolic hypertension is mainly seen in people over the age of 65 and is characterized by a high systolic, but normal diastolic, pressure (a reading of 170/80 mm Hg would be typical). It's caused by an age-related loss of elasticity of the major arteries.

Labile hypertension is a commonly used but inappropriate term for describing people whose pressure is unusually labile or variable. In fact, just about everyone has labile blood pressure.

 

What causes Hypertension?

As described in the previous section, in most people with hypertension there is no single curable cause such as a blocked renal artery, and they are labeled as having essential hypertension. This means hypertension that just happens, although there are a number of factors that we know can contribute to it. The important point is that there is no single factor that causes it, but a combination of several different ones that may play different roles in different people. There is a genetic or hereditary component: if your parents both had hypertension there is an increased chance that you will develop it as well. That component may account for about half of the factors that lead to hypertension. However, it is probable that no single gene is responsible and that more likely a cluster of genes that have different individual effects when acting in concert result in hypertension. There is also a big environmental component. Hypertension is, or was, relatively uncommon in the traditional tribal societies that lived in Southern Africa and elsewhere, but when the villagers moved to the big cities and adopted a more westernized lifestyle their blood pressure tended to increase. Whether this phenomenon is because of stress or changes in diet has not been resolved, but almost certainly both are involved. The typical American lifestyle, with a diet that is high in salt and fat and low in fruits and vegetables, combined with physical inactivity, certainly contributes to high blood pressure. Even more important is obesity, which may account for at least 50 percent of cases of hypertension. The good news here is that a lot can be done to treat and prevent hypertension by attending to diet and exercise.

 

What are the symptoms of hypertension?

Usually, there are no specific symptoms that indicate that someone has high blood pressure. But some population surveys have shown that a wide variety of common symptoms, such as sleep disturbance, emotional upsets, and dry mouth, are slightly commoner in people with higher pressures. The differences are small, however. Going red in the face, or feeling flushed, is not indicative of high blood pressure.

If you asked a hundred people what is the commonest symptom of high blood pressure, the chances are that the majority would say headache. In fact, not only do most people with high blood pressure not have headaches any more than the rest of us, but when they do, it's usually not from the blood pressure. Merely having a high level of blood pressure inside your head does not normally produce any symptoms; if you lift a heavy weight, your pressure may go up by 30 or 40 mm Hg, but you don't get a headache.

What can cause headache is muscle tension. Any muscle that is tensed for long enough starts to hurt, and chronic tension in the scalp or neck muscles is a very common cause of headache. A study conducted many years ago shed some very interesting light on the relationship between headache and high blood pressure. Out of 104 people who had high blood pressure but were unaware of it, only three volunteered that they had headaches, although another 14 admitted it when asked. But of 96 people who had been told that they had high blood pressure, 71 said they had headaches. The simplest explanation for this finding is that being told that you have high blood pressure makes you start to worry, and that this strain in turn causes the headaches.

There is a much smaller number of patients, mostly with very high pressures, in whom headaches are directly related to the height of the blood pressure. In such individuals treating the blood pressure will relieve the symptoms.

 

Treatments

Hypertension is the medical term for high blood pressure. It is not an indication of anxiety, tension or of having a high strung personality.

Your heart pumps blood into the arteries and throughout the body. The blood brings needed oxygen and nutrients to all the body's organs. Blood pressure is the force of the blood pushing against the inner walls of your arteries.

Your blood pressure is at its maximum strength when the heart beats. This is when the heart contracts and pumps blood. Your blood pressure drops when your heart is at rest between beats.

When you have your blood pressure taken, you will get two numbers. The first number represents the maximum strength of the pressure. This is called, "Systolic pressure." The second, represents the minimum pressure. This is called "Diastolic pressure".

Blood pressure is measured in millimeters of mercury (mm Hg). A typical measurement would be 128 mm Hg/72 mm Hg. This represents 128 systolic pressure and 72 diastolic pressure. Your doctor would say, "128 over 72."

High blood pressure forces your heart to work harder than normal to push the blood into your arteries. The harder it is for blood to flow, the higher the numbers will be.

Hypertension can damage your heart and blood vessels and lead to a heart attack. It can also raise your risk of stroke, blindness and kidney failure.

 

Hypertension Program Frequently Asked Questions

What is the relationship between sodium and high blood pressure?

 

Heavy sodium intake increases blood pressure in some people. Your doctor may recommend a sodium (salt) restricted diet to help lower your blood pressure.

That means you will have to avoid salty foods, reduce or eliminate salt in cooking and refrain from adding salt at the table.

The American Heart Association recommends that healthy adults reduce their sodium intake to no more than 2400 milligrams per day. This is about 1-1/4 teaspoons of salt.

Substitute herbs and spices for the salt in your cooking. Experiment with different combinations.

Choose fresh or frozen foods over canned products. If you eat canned products, rinse the salt from the foods. Use fewer "instant" products.

When dining out, ask the waiter to have your meal prepared without any added salt.

Get in the habit of reading food labels. You can look for the different sodium compounds that are added to foods. Watch for the words "soda" "sodium" and the symbol "Na" on labels. These indicate that the product contains sodium compounds.

Make it a practice to read carefully the labels on all over-the-counter drugs as well.. Look at the ingredient list and warning statement to see if sodium is in the product.

 

Can hypertension be treated?

The good news is that high blood pressure is eminently treatable. The objective of treatment is not simply to lower the blood pressure, but to prevent its consequences, such as strokes and heart attacks. The benefits of treatment were first convincingly demonstrated in a landmark Veterans Administration study conducted by Dr Edward Fries, the first results of which were published in 1967. This study included 143 men with severe hypertension who had diastolic pressures between 115 and 129 mm Hg. Half of the men were treated with medication to lower the blood pressure, while the others received inert placebo pills. After only one and a half years, the results were quite clear: in the untreated group, four men had died, and 23 had developed complications such as strokes and heart attacks, while in the treated group none had died, and only two developed complications. This type of study is called a randomized clinical trial. Since this study was published, numerous larger trials have been conducted involving tens of thousands of patients, which have demonstrated conclusively that drug treatment can cut the number of strokes by about half, and of heart attacks by a somewhat smaller amount. These studies have included younger people in whom both systolic and diastolic are elevated and older people in whom only systolic pressure is high. Both groups have shown similar benefit.

Can hypertension be treated without drugs?

People often think that the treatment of hypertension invariably involves having to take medications for the rest of one’s life, but this is not necessarily the case. There is much that can be done with diet and exercise to lower the blood pressure. The traditional recommendation about diet was to restrict the intake of salt (to about 6 grams a day, or just over half the average American’s typical intake), and while this method is still effective, it does not work in everyone. Some people (about one third of the hypertensive population) are "salt sensitive," which means that their blood pressure will respond to changing salt intake, while the rest are "salt resistant," in whom cutting out salt will have little effect on the blood pressure. Unfortunately, there is no simple test to decide who is salt sensitive and who is not.

A major advance in the treatment of hypertension has been the DASH (Dietary Approaches to Stop Hypertension) diet, which has been shown to lower blood pressure as much as medications.

For people who are overweight, the most effective method for lowering blood pressure is to lose weight.

 

What medicines can I take to lower my blood pressure?

 

If you have mild hypertension, your doctor will probably recommend lifestyle changes (exercise, weight loss, sodium reduction), before he prescribes anti-hypertension medication.

If your doctor does want you to take anti-hypertension medicine, there are a number of different types to choose from. Among the most widely used are: diuretics, beta-blockers and calcium channel blockers. Diuretics (sometimes called, "water pills") rid the body of excess fluids and sodium. Beta-blockers lower the heart rate. Calcium channel blockers reduce the heart rate and relax the blood vessels.

Sometimes your doctor will prescribe a vasodilator drug. This medication can relax the arterial wall muscles and widen the arteries. Or he may prescribe an "A.C.E." inhibitor which reduces arterial constriction.

Most medications have potential side effects. Some typical side effects are dizziness, headaches, fatigue, rash, coughing, or blurred vision. Your doctor may experiment with different types of medications to determine the one that works best and has no side effects (or the fewest) for you.

Because most people who have hypertension are not aware of it on a daily basis, they often stop taking their medication or believe it's all right to skip a pill or two. Some people don't know about the dangers of untreated hypertension and believe that they can delay treatment until they are much older.

Antihypertension medication treats your high blood pressure; it doesn't cure it.. If the medication has brought your pressure down to a normal level, you can keep the pressure down by continuing to take your pills. As soon as you stop taking the medicine, your pressure will go up again.

It is important to follow your doctor's instructions explicitly and continue taking your medications.

When you get your blood pressure under control, you can look forward to a longer, healthier life.

Are there factors that contribute to hypertension?

Although you may not know the exact cause of your hypertension, there are several factors that may contribute to it. Some of these factors are beyond your control, but some can be controlled by changing certain aspects of your lifestyle.

The factors you can't control are: heredity, race (African Americans are more likely to have hypertension than people of other ethnic and racial backgrounds), age, and gender, (generally males are more likely to have hypertension),

The factors you can affect are: obesity, lack of physical activity and exercise, sodium (salt) consumption, smoking, stress management, and alcohol consumption.

Some women develop hypertension during pregnancy. If there is a history of hypertension in your family (especially pregnancy-induced), notify your obstetrician early in the pregnancy.

Some women develop hypertension while on oral contraceptives. The likelihood of this increases in women who have other risk factors (e.g. family history, being overweight, or mild kidney disease).

 

What causes hypertension?

Many conditions can cause hypertension. Hypertension may be caused by a narrowing in the arteries. Perhaps there is a greater than normal volume of blood. All these conditions lead to an increased force of blood against the artery walls. When the exact cause of hypertension is unknown, it is called "essential" hypertension.

There are a few diseases, however, of which hypertension is a symptom. Some of these are: kidney disease, tumor of the adrenal gland or congenital defect of the aorta.. When hypertension is a consequence of an underlying disease, it is called "secondary hypertension". Usually when the underlying disease is addressed, the blood pressure returns to normal.

Are there medications that raise blood pressure?

In addition to oral contraceptives, there are other medications that can raise blood pressure and/or lower the effectiveness of your anti-hypertension medication.

If you have hypertension, The American Heart Association recommends that you tell your doctor all the prescribed and over-the-counter medicines you are taking. These include: nasal decongestants and other cold remedies and diet pills.

 

What else can I do to lower my blood pressure?

Regular exercise and physical activity can lower your blood pressure. Not only will exercise reduce your hypertension, but it will help you lose weight.

Give up cigarette smoking. If you do not already have high blood pressure, you will not get it from smoking. If you do have high blood pressure, smoking speeds up the development of a dangerous form of it (malignant hypertension), and increases your risk of developing cardiovascular disease.

Stress raises some people's blood pressure. Learn positive, healthful ways to cope with the stress in your life. Some approaches that have worked for others include: exercise, relaxation techniques, meditation, and psychological counseling.

What is the relationship between hypertension and heart disease?

 

Hypertension is a important risk factor for heart disease. Other risk factors include: age (45 or older for males, 55 or older for women), premature menopause without estrogen replacement therapy, family history, smoking, high levels of cholesterol in the blood, a sedentary lifestyle, obesity, and diabetes.

Untreated hypertension may force the heart to work progressively harder to pump sufficient blood to the body's organs. When this continues for an extended period of time, the heart may enlarge. A significantly enlarged heart does not function well and may not meet the body's demands.

High blood pressure also affects your arteries. Over time, they may become scarred and less elastic. This condition accelerates hardening of the arteries (atherosclerosis) and puts you at a higher risk for heart attack or stroke.

 

How is blood pressure measured?

Your doctor can measure your blood pressure by using an instrument called a sphygmomanometer (blood pressure cuff). She will wrap the cuff around your upper arm. Then she will squeeze a rubber ball to inflate the cuff. As the cuff inflates, it compresses a large artery in your arm. This temporarily stops the flow of blood. Then very slowly, your doctor will let out the air until, using her stethoscope, she hears your heart beat. While she is doing this, she is looking at a gauge.

As soon as the doctor hears your heart beat, she notes the number on the gauge. That is your systolic number. She will continue to let out air until she doesn't hear any more sounds. The doctor will note the number on the gauge. That is your diastolic number.

Sometimes your doctor will measure your blood pressure more than once. She may take it while you are in different positions: sitting up, standing, or lying down. Sometimes she will take it; ask you to rest for a few minutes; and then take it again.

There is a range of normal blood pressures, but normal is usually around 120 mm Hg /70 mm Hg. High blood pressure is 160 mm Hg/90 mm Hg or greater.

Your blood pressure varies throughout the day. It falls somewhat when you are sleeping; and rises when you are awake. Generally, it stays around the same numbers.

What are the symptoms of hypertension?

Most people who have hypertension, have no symptoms. You can go for years of having hypertension without knowing it. That's why untreated hypertension is sometimes called "the silent killer."

If you have headaches, dizziness, fatigue, palpitations, and chest discomfort, it doesn't mean that you have hypertension. Many people have these symptoms for other reasons. It is always wise to report symptoms to your doctor.

 

What if I am overweight?

Overweight people have a greater risk of developing high-normal to mildly high blood pressure than others. Ask your doctor to recommend a good weight loss program. Most likely he will recommend a low salt, low-fat, high fiber diet. A word of caution: sometimes low-fat or reduced fat products contain large amounts of sodium (salt) to compensate for the loss of flavor associated with fat. Make sure to read labels carefully.

In addition to advising you to switch to a lower calorie, low fat, low sodium diet, your doctor may advise you to decrease your consumption of alcoholic beverages. There are two reasons for this. First, alcoholic drinks usually are high in calories Seond, alcohol consumption can raise your blood pressure even if there is no weight gain.


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