High blood pressure (hypertension) is a killer--a silent killer. Directly or indirectly, high blood pressure accounts for nearly a million deaths a year. Uncontrolled, high blood pressure increases the odds that you'll have a heart attack, a stroke, or kidney failure.
Yet, high blood pressure is not like a toothache, a bruise, or constipation. Usually, people with high blood pressure experience no discomfort or outward signs of trouble.
Blood does not simply flow through the circulatory system on its own.
The heart pushes it, and the force with which it pushes is called blood pressure.
The classic analogy used to explain this phenomenon is that of a garden hose: When the nozzle is open, the walls of the hose are under very little pressure and water pours out easily, but when the opening in the nozzle is narrowed, the pressure of the water against the walls of the hose is higher. If the body’s blood vessels are narrowed, the heart must pump harder than normal against the resistance. This is called high blood pressure, or hypertension.
When the heart enlarges, the muscle thickens, the heart needs more oxygen to function, and it becomes less efficient. After many years, heart failure may result. The high pressure of the blood within a blood vessel is a factor in driving blood fat or cholesterol into the vessel wails, speeding up the process of atherosclerosis. This increases the possibility of a stroke or heart attack occurring as a result of clot formation.
A stroke is also as same, because increased blood pressure over many years causes a ballooning of a blood vessel (aneurysm), and this may, under certain circumstances, burst. This results to cerebral hemorrhage.
Over time, high pressure can also scar the body's arterioles (small arteries), reducing their ability to carry blood to specific areas of the body. An example of this is a progressive loss of kidney function as a result of damaged vessels.
Hypertension usually is present without any symptoms; hence it is sometimes called the silent killer.
In advanced stages the symptoms include
loss of renal (kidney) function,
in late stages, convulsions and swelling of the brain.
Many who have high blood pressure don't know it. Yet, nine out of ten people who know their blood pressures are unhealthfully high are doing nothing to try to control it.
Although the origin of hypertension in about 90 percent of patients is unknown (this is called primary hypertension), it is known that the level at which blood pressure settles is controlled by a complex interaction of hormones, chemical cell receptors, sodium intake (in some people), and the nervous system.
In the remaining 10 percent of patients, high blood pressure is a symptom of an underlying problem such as narrowing of the arteries supplying the kidneys, a kidney abnormality, tumor of the adrenal gland, or congenital defect of the aorta. This is called secondary hypertension.
Mild high blood pressure can sometimes be treated by restricting the amount of sodium (salt) in the diet and controlling weight. If these measures are not effective, there are several classes of medications that work to reduce the heart rate and thus the output of blood; cause the muscles in the blood vessel walls to relax; prevent the nerves from contracting the blood vessels; or interfere with the body’s production of angiotensin, a chemical that causes the arteries to constrict.
In the majority of cases—over 90 percent—no specific cause for the elevated blood pressure can be identified. In this case, the elevated blood pressure is referred to as primary or essential hypertension. Some researchers believe that this type of high blood pressure may be due to hormonal factors relating to the handling of salt by the kidneys and/or to the elaboration of certain substances that cause constriction of blood vessels. These are probably genetically determined, but certain environmental factors, such as a high-salt, low-potassium diet and chronic stress, may play some role.
In up to 10 percent of patients, high blood pressure may be a consequence of another disorder, or a side effect of medication. This type of hypertension is referred to as secondary hypertension. lt is important to remember that these cases are relatively uncommon. However, some of the more common causes of secondary hypertension include the following.
About 4 percent of all cases of high blood pressure can be traced to some type of kidney (renal) disorder. The kidneys work in several ways to help regulate blood pressure. For example, they are instrumental in regulating the body’s fluid volume and its balance of sodium (salt) and water. If the kidneys conserve too much sodium, the body’s fluid volume increases. In turn, this increased fluid volume puts an increased burden on the heart to maintain an adequate flow of blood to tissues and causes blood pressure to rise.
The kidneys also produce renin, an enzyme that plays a key role in regulating blood pressure. About 2 to 3 percent of all cases of high blood pressure are the result of recurrent kidney infection or a bout of nephritis . But almost any chronic kidney disorder can result in elevated blood pressure. An example is damage to the kidney’s blood vessels caused by diabetes. As a rule, doctors will probably suggest specific tests of kidney function in cases of high blood pressure that do not respond to conventional antihypertensive (blood-pressure-lowering) therapy, especially if a urinalysis shows protein in the urine—an indication of impaired kidney function. It should be noted, however, that long-standing, poorly controlled hypertension by itself can cause kidney damage. In fact, about 25 percent of patients who require kidney dialysis have renal failure that is due to hypertension. This is especially true in the African-American population.
The renal arteries, which carry blood to the two kidneys, branch off from the abdominal aorta. A narrowing in one or both of the renal arteries results in reduced blood flow to the kidneys. This prompts the kidneys to attempt to raise blood pressure in order to improve their own blood supply. To do this, the kidneys increase their secretion of renin, an enzyme that, through a series of biochemical changes in the kidneys and lungs, gives rise to a substance called angiotensin II This is a powerful vasoconstrictor, a medical term used to describe substances that cause blood vessels to narrow, or constrict. This constriction results in increased blood pressure. This substance also increases the secretion of a hormone, aldosterone, which leads to a retention of salt and water—further increasing blood pressure.Renovascular hypertension is rare (accounting for 1 to 2 percent of all cases of hypertension), but it is relatively more common in elderly persons who may have widespread hardening of the arteries. It tends to occur more frequently in smokers. It sometimes occurs in children, as a result of infection or an inflammatory condition. In fact, renovascular hypertension is one of the more common causes of high blood pressure in young children, and should be suspected in any youngster under the age of 10 to 12 with elevated blood pressure. Less commonly, renovascular hypertension may be due to an inflammatory disorder that affects the muscles that encircle the arteries and control their diameter. This type of renovascular hypertension occurs more frequently
in young women, although it is occasionally seen in men. It also tends to develop more frequently in smokers than in nonsmokers.
MAJOR CARDIOVASCULAR DISORDERS
Renovascular hypertension can be diagnosed by studies in which a contrast dye is injected into a vein or artery to visualize the kidneys’ blood vessels on Xray film. Widening or opening up the narrowed renal artery will often cure this type of high blood pressure. The widening may be accomplished by angioplasty, a procedure in which a catheter with a balloon tip is inserted into the renal artery. The balloon is inflated at the site of narrowing to stretch the artery and increase blood flow. In some cases, surgery may be necessary to put in a bypass graft or bridge around the narrowed segment of the artery. The cure rate is high in carefully selected cases.
The two adrenal glands, which rest atop each kidney, secrete a number of hormones, including aldosterone. This hormone is instrumental in maintaining the body’s fluid and electrolyte or mineral balance by regulating potassium secretion and prompting the
kidneys to conserve sodium. In rare instances (fewer than 0.5 percent of all cases of hypertension), an adrenal tumor develops and production of aldosterone is increased. The elevated aldosterone results in the body's excreting too much potassium and conserving too much sodium. The extra sodium increases the body’s fluid volume, leading to high blood pressure. These tumors are benign except in extremely rare instances.This type of hypertension is rare, but should be suspected if a person develops high blood pressure and experiences other symptoms, such as muscle weakness, thirst, and excessive urination. Younger women are more susceptible to this disease than other people. But one should also keep in mind that excessive thirst and urination may be symptoms of other illnesses, such as diabetes. A diagnosis can be established by blood and urine studies and a computed tomography (CT) scan of the adrenal glands. CT scan is an examinati on that uses a computer to create a cross-sectional view of internal organs from multiple X-rays. Removal of the adrenal tumor usually cures the high blood pressure. If, however, excessive aldosterone secretion is due to overactive adrenal glands instead of a specific tumor, medication can be prescribed to block the hormone’s action.
This is another very rare type of secondary hypertension that is related to a different type of a tumor of the adrenal gland called a pheochromocytoma. This type of tumor, which is benign in about 90 percent of all cases, produces different types of hormones,specifically adrenaline-like substances. As noted earlier, these hormones are instrumental in the body’s fight-or-flight response. They serve to get us ready for emergencies or help us to exercise vigorously. Adrenaline increases the heart rate, elevates blood pressure, and helps increase blood flow to leg muscles. In addition to elevated blood pressure, the hormone elaborated by a pheochromocytoma may cause palpitations, tremors, clammy skin, jittery feelings, and facial and body sweating even in a cool room. The symptoms, including high blood pressure, may come and go.
The tumor usually develops on the adrenal glands,but in fewer than 10 percent of even these rare cases,it arises elsewhere in the body, usually along the aorta or spine, in the chest, or in the bladder. There are,however, only a few of these tumors reported yearly worldwide. If a pheochromocytoma is suspected, the patient may be asked to collect his or her urine over a 24-hour period; this is then analyzed for excessive amounts of adrenaline. X-ray studies or a CT scan may be ordered to locate the tumor(s), which can then be removed surgically. This removal usually cures the high blood pressure unless it has been present for some time, in which case antihypertensive medication may still be needed to keep blood pressure within normal limits.
Some drugs that are used for other conditions can raise blood pressure. Examples include birth control pills, the use of which may result in a small rise of 5 to 10 mm Hg in many women and a greater increase in about 1 in 30 to 50 women. The use of cortisone or other steroid medications and of certain nonprescription drugs, including some cold remedies, diet pills, arthritis medications such as the nonsteroidal anti-inflammatory agents Indocin, Naprosyn, etc.,and nasal decongestants, may also increase blood pressure. Glycyrrhizic acid, an ingredient in natural licorice candy, can also raise blood pressure if consumed in large quantities. In almost all of these cases, blood pressure usually returns to normal when the causative substance is stopped. In some instances, the use of one of these medications may unmask a previously undiagnosed case of hypertension.
HYPERTENSION IN PREGNANCY
There is a type of hypertension that may develop in the last three months of pregnancy as part of toxemia of pregnancy. (See Chapter 19.) Since blood pressure levels in pregnancy are usually on the low side of normal (90–110/70–75), any increase to levels of above 135-140/85–90 should be considered as elevated, and some treatment should be instituted.
Ways to Control
Blood pressure is one of the easiest health problems to control.Periodical blood pressure checking more than once on several occasions. If your blood pressure is generally pretty good and suddenly registers high, don't be alarmed. Anxiety and other strong emotions, physical exertion, drinking a large amount of coffee, or digesting a recently consumed meal can temporarily elevate normal blood pressure with no lasting effects.
To understand why lowering high blood pressure is so important in preventing heart and blood vessel to the brain we can give many examples. Good examples of this bodily response are the numerous instances of healthy soldiers who fainted after standing at attention for long periods of time in hot weather. Other reflexes maybe triggered and result in a sudden loss of blood to the brain and an episode of light-headedness or fainting. These episodes are not serious but can be frightening. An example
of this response is fainting after only a small amount of blood is drawn for a blood test. A nerve reflex slows the heart and causes blood vessels to dilate or open up, Less blood gets to the brain and fainting occurs. As we all know, if the affected individual rests quietly for just a few minutes, all is well. To understand why lowering high blood pressure is so important in preventing heart and blood vessel to the brain. Good examples of this bodily response are the numerous instances of healthy soldiers who fainted after standing at attention for long periods of time in hot weather. Other reflexes maybe triggered and result in a sudden loss of blood to the brain and an episode of light-headedness or fainting. These episodes are not serious but can be frightening. An example of this response is fainting after only a small amount of blood is drawn for a blood test. A nerve reflex slows the heart and causes blood vessels to dilate or open up, Less blood gets to the brain and fainting occurs. As we all know, if the affected individual rests quietly for just a few minutes, all is well.
Some other ways to control Blood Pressure :
If you're overweight, lose weight
Limit alcohol to two drinks or less a day.
Eat a low-salt diet and use salt substitutes if your physician says it's okay.
Get regular exercise at least three times a week.
Learn to handle stress by practicing relaxation techniques and rethinking stressful situations.
Take any prescribed blood pressure medicine as directed. Don't skip your pills because you feel fine.
If you're a woman, talk to your doctor about oral contraceptives and blood pressure. Many other birth control methods are available.
Avoid over-the-counter cold remedies containing the ingredient phenylpropanolamine. It can raise blood pressure. Talk to your physician or pharmacist.
Blood pressure is normally measured with a blood pressure cuff placed on the arm. The numbers on the gauge measure your blood pressure in millimeters of mercury (mmHg). The first (higher) number measures the systolic pressure. This is the maximum pressure exerted against the arterial walls while the heart is beating. The second (lower) number records the diastolic pressure, the pressure between heartbeats, when the heart is resting. The results are then recorded as systolic/diastolic pressure (120/80, for example). The term hypertension means high blood pressure.
Blood pressure is regulated by an intricate system of hormonal controls and nerve sensors, and it may vary considerably during the course of a day. Typically,blood pressure is low when you are resting or asleep, and higher when you are moving about or under stress. For example, when you are frightened or angry, the adrenal glands pump out epinephrine and norepinephrine, stress hormones that are commonly referred to as adrenaline. These hormones, which are responsible for the body’s fight-or-flight
response, signal the heart to beat faster and harder, resulting in increased blood pressure and flow to the muscles. It is apparent that pressures are typically lowest between 1:00 and 4:00 or 5:00 A.M., rise rapidly during “arousal” from sleep between 6:00 and 8:00 A. M., remain at approximately the same levels during the afternoon and evening, and decrease from about 11:00 to 12:00 at night.
The accompanying table gives the normal and abnormal ranges for both systolic and diastolic blood pressures for adults age 18 or older. To accurately determine your blood pressure, an average of two or more readings should be taken on two or more separate occasions. The risk of stroke, heart attack, and kidney disease increases when blood pressure is in the mild to severe range. So have your blood pressure checked at least once a year, and follow your physician's advice if it is abnormal.
Blood Pressure in Adults
What Constitutes High Blood Pressure?
|Diastolic Blood Pressure
|84 or less
||Normal blood pressure
||High normal blood pressure
|115 or greater
|Systolic Blood pressure
|139 or less
||Normal blood pressure
||Borderline systolic hypertension
|160 or greater
Blood does not flow in a steady stream; instead, it moves through the circulatory system in spurts that correlate with the heart’s beats. The heart beats about 60 to 70 times a minute at rest and may speed up to 120 to 140 or higher during vigorous exercise, It is
not contracting or squeezing all the time, however; after each contraction, the heart muscle rests and gets ready for the next beat. Blood pressure rises and falls with each beat. Thus, blood pressure is expressed in two numbers, such as 120 over 80, or 120/80. The higher number, which is called systolic pressure, represents the maximum force that is exerted on the walls of the blood vessels during a heartbeat. The lower number, which is referred to as the diastolic pressure, is the amount of force exerted when the heart is resting momentarily between beats. Blood pressure is usually measured with a device
called a sphygmomanometer , which consists of an inflatable rubber cuff, an air pump, and a column of mercury or a dial or digital readout reflecting pressure in an air column.
Readings are expressed in millimeters of mercury or mm Hg. The cuff is wrapped around the upper arm, and the inflatable cuff is tightened until blood flow through the large artery in the arm is halted. As air is pumped into the cuff, it pushes
up a column of mercury or air, in the case of the simpler machines. The person measuring the blood pressure places a stethoscope over the artery just below the cuff and listens for a cessation of the sound of blood coursing through the artery. He or she then begins to release air from the cuff, allowing blood to flow through the artery again. As air is released, the column of mercury or air begins to fall, and the person listens for the first thumping sound that signals a return of blood flow into the vessel over which the stethoscope has been placed. The height of the column of mercury or the air pressure on the dial at this sound indicates the systolic (or higher) pressure. More air is released from the cuff, and pressure continues to fall. The height of the mercury or the level of air pressure when the thumping sound of blood ceases, indicating the pause between heartbeats, is the diastolic pressure.People with high blood pressure can learn to monitor
their own pressure .
As noted earlier, blood pressure varies considerably during the course of an average day. It also varies according to age—a baby’s blood pressure may normally be 70/50, whereas the average blood pressure in an adult is about 120/80. Until recent years,
there was no clear agreement among physicians as to what constituted high blood pressure, but now it is generally agreed that blood pressure readings that are consistently above 140/90 warrant a diagnosis of hypertension, and the higher the readings, the more
serious the disease. A reading of about 140/90 does not necessarily indicate that the condition requires immediate therapy, but it does suggest follow up and some treatment.
High blood pressure develops in all social and economic groups, and affects both men and women. It generally begins in adulthood between the ages of 35 and 50, although it also occurs to a lesser extent among children and younger adults. Hypertension is
rather uncommon in preadolescent children, but blood pressure should be checked at age 2 to 3 and again at age 13 to pick up the rare cases. The younger the age, the more probable that a secondary cause of hypertension will be found. Some people are more
susceptible to hypertension than others, including:African-Americans. Not only are blacks twice as likely as whites to develop hypertension, but their disease is also more severe.
People with a family history of the disease. Babies born to parents who have hypertension tend to have higher-than-average or more variable blood pressures throughout infancy and childhood, and are more likely to develop hypertension
at a relatively early age. This tendency strongly suggests that there is a genetic
basis for at least some cases of high blood pressure.It does not mean, however, that if both parents have hypertension the offspring will always develop high blood pressure.People with diabetes.People who are overweight.
Epidemiological, or population, studies suggest a number of other factors that may increase the risk of having high blood pressure. These include consuming large amounts of salt (sodium) and alcohol (more than the equivalent of 3 to 4 ounces of alcohol daily),smoking cigarettes, and following a diet low in potassium. The exact mechanisms by which these factors raise blood pressure have not been clearly identified; some people appear to be more susceptible to them than others. For example, a high-salt diet may raise blood pressure only in people who have a genetic tendency to conserve sodium. Similarly, many people who consume excessive amounts of alcohol
have normal blood pressures.
A diagnosis of high blood pressure should not be based on a single reading, except when it is extremely high—for example, above 170–180/105–110. Other-wise several measurements taken over a period of time are generally needed to confirm a diagnosis. This is why single readings obtained at health fairs or other blood pressure screening events are often misleading.
In addition, the electronic machines used for self-measurement at airports or in pharmacies are often poorly calibrated or improperly used and may give false readings (usually on the high side), Although hypertension screening has its place, people
should understand that readings obtained are only an indication to follow up more carefully, and do not justify a definite diagnosis of high blood pressure or
hypertension. Unfortunately, many people are unduly frightened, on the basis of just one blood pressure recording, into thinking they have hypertension. The circumstances under which blood pressure is measured must also be taken into consideration. For example, a blood pressure reading taken when a person is under severe stress maybe misleadingly high. Similarly, a high reading may be obtained if blood pressure is measured soon after a person has had a couple of cups of coffee or smoked a few cigarettes.
Thus, if possible, a person should avoid smoking and/or drinking coffee, cola, or other sources of caffeine for about one to two hours before having blood pressure measured. In a physician’s office or clinic, blood pressure is usually measured after the doctor has asked questions about the patient’s health history. This also gives the patient a few minutes to relax, although some people remain anxious. Two readings may be taken—the first with the person seated, and the second while standing. The reading while standing may be especially useful in older persons whose pressures may fall when they stand up. And it can help to guide treatment decisions, since some blood-pressure-lowering drugs may cause a greater decrease in standing than in sitting blood pressures.
Blood pressure may be measured several times during the visit, especially if the first reading was on the high side, The results of all the readings are then usually averaged. In an adult, blood pressure recordings need only be repeated every one to two years if pressures are below 140/90. If the average falls in the mild to moderate range of high blood pressure, about 140/90 to 160/100, an appointment for additional measurements will be made to confirm the diagnosis. However, very high diastolic blood pressure readings (more than 110 to 115 mm Hg) during the course of an office visit justify starting treatment. If an elevated blood pressure is present in individuals below 60 years of age, both the systolic and diastolic levels are usually high—for example, above 140 systolic and 90 diastolic. In older people, however, there is a form of hypertension called isolated systolic hypertension. The systolic, or upper, reading may be high, for example, 150–180, but the diastolic, or lower, reading is below 90. This type of hypertension also results in an increased risk of stroke, heart attack, or heart failure. In addition to measuring blood pressure, the doctor will also look for signs of organ damage, if the readings are high.
The examination will include:
* Inspection of the eyes. The eyes are the only place in the body where blood vessels can be looked at directly. By shining a bright light into the eye and inspecting its interior with an ophthalmoscope (a special magnifing device), the doctor can inspect the blood vessels for thickening or narrowing, changes that are characteristic of high blood pressure. He or she will also look for tiny hemorrhages inside the eye, another possible sign of damage from high blood pressure.
* Examination of the heart. This includes a careful examination using a stethoscope to listen for any unusual sounds or beats and palpation of the heart impulse to judge heart size. An electrocardiogram will measure the hearts electrical activity and help to determine if the heart is enlarged.
* A check of blood flow in the arteries. Pulses will be felt at various parts of the body, including the wrists, neck, and ankles. The doctor may use a stethoscope to listen to blood flowing through the carotid artery, the large blood vessel in the neck that carries blood to the brain.
Examination of the kidneys. By pressing on the abdomen, a doctor may be able to tell if the kidneys are enlarged, which may indicate a specific
type of hypertension. This type of high blood pressure is rare.
A check for an enlarged thyroid. A swelling in the neck (a goiter) may be a sign of an overactive or underactive thyroid, conditions that can elevate blood pressure.A humming noise (called a bruit) may indicate In addition to the physical examination, the doctor will also check for narrowing of artery. Similarly, the doctor will likely order a urinalysis to check for possible kidwill probably listen for bruits in the abdominal ney damage or a bladder infection, and blood tests, arteries that carry blood to the kidneys. If a especially to measure blood sugar (glucose) and chospecific kind of bruit or murmur is found it may lesterol levels and to estimate kidney function. Any indicate that the high blood pressure has re- abnormality in either the physical examination or lab suited from a narrowing of one of the arteries studies that indicates possible damage to the heart, of the kidneys. kidneys, eyes, or blood vessels (the major “target” organs of high blood pressure) may warrant additional testing. In most cases, however, a diagnosis of high
blood pressure and its severity can be established accurately by repeated measurements with a sphygmomanometer and a few simple tests.
The development of a variety of effective medications to control high blood pressure is one of major accomplishments of medical science since the 1950s.Before then, treatment was limited to strict restriction of sodium, radical surgical procedures, and drugs such as phenobarbital that were not particularly effective.All too often, patients developed malignant or accelerated hypertension, a complication marked
by rapidly rising blood pressure, usually culminating in a stroke, heart or kidney failure, or some other catastrophic event. In fact, this is what led to a crippling
stroke in President Woodrow Wilson in 1917 and what killed President Franklin Roosevelt in 1945. In the late 1940s, it was not uncommon to find that every third or fourth bed in a hospital was occupied by a patient with some kind of complication of
hypertension. A decade later, the first effective antihypertensive drugs were introduced, and today, dozens of medications that lower blood pressure are available. As a result, malignant hypertension is now so rare that it is considered a medical oddity. Even at a major center like the Yale–New Haven Hospital,it is unusual to find more than just a few patients in the entire facility who are there because of high blood pressure. This change is exciting.
Many misconceptions persist about when and how high blood pressure should be treated. Most doctors agree that even mild hypertension (repeated readings over 140/90) should be treated. (Treatment may not merely imply the use of drugs, as discussed below.)
Some dissenters, however, advocate waiting until blood pressure reaches a higher level (blood pressures above 145–160/95-105) before initiating treatment.
Numerous studies showing decreased mortality and target-organ damage document the benefits of treating mild high blood pressure. These studies, carried out in the United States, Europe, and Australia, have involved over 40,000 men and women between
about 40 and 80 years of age. They have demonstrated not only that lowering blood pressure will prevent progression to more severe hypertension, but that effective therapy also prevents heart attacks,heart enlargement, heart failure, strokes and stroke death, and progression of kidney damage. In other words, the occurrence of cardiovascular disease can be markedly decreased in both sexes and, importantly,
in both young and elderly individuals by modern treatment of high blood pressure. Before initiating drug therapy, however, most doctors put patients on a trial of three’ to six months of nonpharmacologic life-style modifications, unless pressures
are very high (greater than 160–180/100–110).These nondrug treatments include the following.
Reducing Sodium Intake
Early in the century, doctors first recognized that sodium restriction lowered high blood pressure. (Ordinary table salt is made up of sodium and chloride,and sodium is a major ingredient in many flavorings and preservatives,) Before the development of effective antihypertensive medications, a strict low-salt diet such as the rice and fruit diet developed by Dr. Walter Kempner at Duke University Medical Center
was one of the most effective treatments for high blood pressure. The problem, of course, was that most patients had difficulty sticking to such a restrictive
diet. In the days when we had nothing else to offer, some patients did stay on this diet for long periods of time. Today's low-salt diet allows many more foods and flavorings and does not have to be
nearly as rigid. Care must be taken in selecting from a large variety of processed foods—our major source of sodium—if sodium is to be restricted.If it proves ineffective, other methods of treatment
In reducing sodium intake—as in all aspects of lifestyle modification-common sense and moderation should prevail. Contrary to popular belief, scientific data do not confirm that salt is a major cause of high
blood pressure or that eliminating it from your diet will always prevent high blood pressure. Sodium is probably a contributing factor only among people who are salt-sensitive, i.e., whose blood pressure
goes up or down as they eat more or less sodium. Only about a third of hypertensive Americans may fall into this category. For reasons that are not completely
understood, African-Americans tend to be more sodium-sensitive than Caucasians. Since many of the ethnic dishes favored by African-Americans are high in salt, this may be one reason that high
blood pressure is more prevalent and severe in this segment of the population.The typical American diet provides about 10 to 15 grams of salt (about 3-4 teaspoonfuls) a day, which is far more than we need. For most people, this extra sodium is not a hazard. The exceptions are the hypertensive
patients who may be salt-sensitive.
So, what should you do if you have a strong family history of hypertension in both parents and you hope to prevent hypertension, or you have a higher blood pressure than normal and you would like to lower it without any drugs?
Try to reduce your salt intake to about 1-1½ teaspoonfuls (about 4-6 grams) a day. You can do this by Not using salt on food at the table. Avoiding obviously salty foods—processed meats, peanuts, pretzels, ketchup, and so forth. Using less salt in cooking and using other spices or condiments, such as salt-free herb
If you are salt-sensitive, this degree of sodium restriction will probably work in many cases; if not, other measures can be used to lower blood pressure. Some individuals are able to restrict salt to a great degree (to about 2 grams or less per day) without being miserable. It is possible that this degree of restriction may be more helpful in either preventing or treating high blood pressure—but there is no guarantee, and it does represent a sacrifice and a major
change in life-style.
Maintaining a Moderate Alcohol Intake
As noted earlier, there is some evidence that a moderate intake of alcohol may actually help lower the risk of cardiovascular disease. There is also evidence that an intake of more than 3 ounces of alcohol a day may increase the risk of developing high blood pressure or cardiovascular disease. No more than 1 ounce of ethanol a day. This amount is contained in 2 ounces of 100-proof whiskey, about 8 ounces of wine, or about 24 ounces of beer.
All bets are off, however, if there is a strong family history of alcoholism or a sensitivity to small amounts of alcohol. In these cases, a person should not drink any alcohol regardless of the recommendations. The good news is that alcohol in moderation is acceptable in most people. But drinking more than a few drinks a day might be harmful, not only to the brain and liver, but also to the cardiovascular system. In a number of cases blood pressure has become easy
to control once patients have reduced their excessive intakes of alcohol.
Losing Excess Weight
It has long been known that people who are obese (20 percent or more above desirable weight) have an increased incidence of high blood pressure. They also are more likely to have high blood cholesterol and to develop diabetes. In many of these overweight and/ or diabetic patients, losing excess weight will normalize blood pressure and may also control the diabetes. This improbably the most important thing other than stopping smoking that someone can do to reduce his or her risk of heart disease and possibly to reduce blood pressure.
A common-sense diet that reduces the intake of total calories and fats (especially animal and other saturated fats) and emphasizes complex carbohydrates (starches) as the major diet component (55 to 60 percent of calories consumed) may help control many of the risk factors that predispose to early cardiovascular disease. Crash diets should be avoided.
Although they may produce a fast weight loss, in more than 90 percent of cases, the pounds are quickly regained once the diet is stopped. Instead, strive for gradual weight loss—l or 2 pounds a week—and undertake a moderate increase in physical activity. Such a program is more likely to achieve long-term weight control than a crash diet. There are no miracle diets.
Increasing Physical Actvity
Moderate exercise, combined with weight reduction
and a low-salt diet, is an important component in any
nondrug treatment program for high blood pressure.
Some studies have shown that increased exercise can
produce a modest lowering of blood pressure. It also
helps burn up some calories and control excess
weight, and it adds to the sense of well-being. A recent
well-controlled 4-month study reported, however,
that blood pressure was no more reduced in
those who completed a regimen of vigorous aerobic
exercise than it was in the control group.
Exercise need not be a regimented or rigorous
cardiovascular conditioning program—activities
such as taking a brisk walk, playing tennis regularly,
cycling, and swimming all provide excellent means
of relaxation and provide almost all of the benefits in
terms of reducing cardiovascular risk that are derived
from vigorous exercise. Nor is it necessary
to set aside a time to exercise everyday unless
you want to—studies show that 15 to 30 minutes of
moderate exercise three times a week provide the
desired results. The exercise should be convenient
and enjoyable; otherwise, you’re likely to give up after
an initial burst of enthusiasm. Remember, too, that
many day-to-day activities-walking up two or three
flights of stairs, working around the house or yard
—are excellent forms of exercise. A long-term study
of nearly 17,000 Harvard alumni found that those who
burned an extra 2,000 calories a week in moderate
activities such as recreational sports, or walking or
climbing up several flights of stairs a day, had a lower
death rate than their more sedentary counterparts.
A moderate exercise program plus a low-salt diet
may lower blood pressure by anywhere from 1 to 10
mm Hg systolic and 1 to 8 mm Hg diastolic. If you
start with a pressure of 145/95 and are one of the
lucky responders, your pressure may decrease to below
140/90 and you will not have to take medication.
Unfortunately, and contrary to what some popular
media tell us, nondrug treatment methods will be effective
in only 20 to 25 percent of cases of high blood
pressure. Moreover, some nondrug treatments are
highly questionable. So although we
all would like to be in control of our own destiny and
not depend on medications, the majority of individuals
with hypertension will have to take some
medication to bring their blood pressures down to