HomeHealthArchivesApr 2006

 

 

Hypertension or High Blood Pressure

What is high blood pressure?

High blood pressure is too high of a pressure in the arterial side of the blood system.

Prevalence of hypertension:

Perhaps 50 million Americans or more have elevated blood pressure. Despite improvements in awareness and treatment, as many as 35 percent of Americans with elevated pressures still are not even aware that they have a problem.

As a person in the U.S. ages, blood pressure tends to rise. In the U.S. the average person's systolic pressure rises by 15 points between the ages of 25 and 55. About 60 percent of Americans aged 65 to 74 have high blood pressure.

How high is too high?

The number seems to have fallen recently: over about 130 to 133 on the top or systolic and over about 80-85 on the bottom number may increase risk of disease.

What damage can be done by high blood pressure?

In the book Proof Positive by Neil Nedley, M.D. we see that stroke is caused by hypertension through at least two different mechanisms. First, high blood pressure predisposes individuals to atherosclerosis (often called "hardening of the arteries"). In this process, large and medium sized arteries throughout the body become narrowed by a buildup of fatty material. Atherosclerosis commonly strikes the vessels in the head and neck that carry blood to the brain. Evidence testifies that high blood pressure can damage the cells that line these blood vessels. This damage appears to be one of the ways that the process of atherosclerosis is initiated or perpetuated.

The body does not sit idly by as its vessels accumulate fat. It responds by covering the fatty deposits with a tough fibrous cap. This is an important response. If fatty material comes into direct contact with blood it can stimulate the blood to clot. The fibrous cap helps to ensure that such an event will not occur. It is actually this dual process which gives atherosclerosis its name. "Athero" refers to the "mushy" or "gruel-like" fatty material and "sclerosis," meaning "hard," designates the body's fibrous walling off of this material.

Unfortunately, areas of atherosclerosis, called plaques, can ulcerate. When this happens, the fibrous cap is lost or damaged. A combination of fibrous and fatty material is released into the blood stream. A now smaller, eroded fatty deposit is left on the artery wall; this is called an ulcerated plaque. If a plaque in a blood vessel supplying the brain breaks down in this way, the result can be a "mini stroke" or TIA (transient ischemic attack). These episodes are very similar to strokes, but they resolve completely. Full recovery occurs within minutes to hours.

Worse yet, however, ulcerated plaques can activate platelets, the clotting cells of the body. This often sets in motion a chain of events that can completely obstruct any artery that is already narrowed by atherosclerosis. If complete obstruction occurs in an artery supplying blood to part of the brain, the brain tissue that was dependent on that artery will die. This death of brain tissue is called a stroke.

A second way that high blood pressure causes strokes is by causing more severe damage to brain blood vessels. In this scenario, cumulative damage to the artery is so severe that the vessel ruptures and bleeds. These so-called hemorrhagic strokes are particularly dangerous. The bleeding often continues for some time. Since the brain is encased in a rigid shell called the skull, it has no place to go when an accumulation of blood competes with it for room. The more blood that accumulates, the more the pressure rises inside the brain. If the bleeding does not stop, part of the brain can actually be pushed down through the small opening for the spinal cord. This is called "herniation of the brain" and generally causes death rapidly.

This mechanism, or one very similar probably occurs in arteries to other important organs in the body. But the effects of loss of brain function are more striking than perhaps loss of supply to part of an arm muscle.

How Much Stroke Risk Does High Blood Pressure Cause?

Studies have shown that the risk of developing atherosclerosis (mainly ischemic heart disease and cerebrovascular disease) is five times greater for those whose blood pressure is 160/95 than those with normal blood pressure.

Risk apparently begins to rise at the 120 to 129 level even though this range is frequently called "normal." Risk rises even more sharply at higher pressure levels. Still, to minimize risk, blood pressure should be below 120 systolic. In other words, do not be satisfied when someone tells you that your blood pressure is "normal." Make sure that it is below that 120 level. This stricter guideline means many Americans must get more serious about their lifestyle. Nearly half of our male population has a systolic pressure of 130 or greater.

While for a long time, it was thought that diastolic blood pressure should be below about 85 to 90, it appears that at least in diabetic, the number should be down around 80 or less. I suspect that this would be more healthful for nondiabetics as well.

What about the kidneys?

Kidney failure is another disease caused by high blood pressure, and the higher the pressure the greater the risk. In fact, in the United States high blood pressure is the second leading cause of kidney failure. (The first is diabetes). Kidney failure and its relationship to high blood pressure were studied in more than 300,000 men over a 16-year period.

The study also showed that a very mild increase in blood pressure to 127 systolic increased the risk of kidney failure later in life by 50 percent. How does high blood pressure harm the kidneys? It actually destroys nephrons, those tiny microscopic filtering cells that make the kidney function. By gradually destroying one nephron after another, the kidney's ability to cleanse the blood becomes progressively compromised. We use the term kidney (or renal) failure when this purification function becomes so impaired that toxin levels build up in the body. With early kidney failure there may be no symptoms. As the disease progresses, a person tends to develop nausea and fatigue. Ultimately, when kidney function becomes markedly impaired, death occurs-unless dramatic steps are taken. Such steps may include dialysis or kidney transplant. Without dialysis machines many people would die sooner from the consequences of their high blood pressure. However, even with dialysis, many experience a short extension of life accompanied by a significant decrease in their quality of life. For this reason, some people have even chosen to die rather than to begin or continue with dialysis.

Is there a relation between high blood pressure and decreased mental ability?

Numerous studies have documented that high blood pressure that is not controlled by lifestyle frequently causes gradual mental decline. One recently published study showed that for every 10 mm of mercury increase in systolic blood pressure at midlife, there was a 9 percent increased risk of poor intellectual ability 25 years later.

What about quality of Life and High Blood Pressure?

The toll that high blood pressure takes on the kidneys reminds us that high blood pressure does more than kill. It robs us of quality of life. "Morbidity level" is a measure of the illnesses that cause suffering and detract from life's quality. Morbidity increases once a person's blood pressure creeps over that 120 level. It may not be surprising to see that those with a systolic blood pressure greater than 160 have four times the risk of morbidity as those with a systolic blood pressure of less than 120. The risk doubles even when you move from less than 120 into the 120 to 139 range.

Since there are benefits to having systolic blood pressures of 120 or lower, why do physicians tend to avoid prescribing medications that help patients drop their blood pressures from, say, 130 systolic to 118 systolic? One reason is that all high blood pressure drugs have side effects. When pressures are only mildly elevated above the ideal, the risk of taking a drug is generally greater than the benefit of further lowering the blood pressure.

Is there an association between heart disease and high blood pressure?

Yes, lower blood pressure seems to be associated with lower risk of heart disease. This may be related to less damage to the arteries that supply the heart muscle occurring with lower blood pressure.

What kinds of blood pressure exist?

There are two large categories of high blood pressure.

The first and less common is the high blood pressure that is caused by other problems we can find such as: over production of hormone by the adrenals or overproduction of thyroid hormone by the thyroid. Disease of the artery supply to a kidney or disease of the kidneys themselves can also cause high blood pressure.

Treating the problem that leads to one of these types of high blood pressure may solve the blood pressure problem.

The much more common cause of high blood pressure is primary high blood pressure or high blood pressure that occurs without an obvious known cause. This may be associated with a less-than-desirable lifestyle.

How can blood pressure be treated?

The most desirable way to treat a high blood pressure is with lifestyle measures: The National Institute of Health sponsored a study that demonstrated the power of lifestyle changes to lower blood pressure. Over 900 subjects (men and women, black and white) with mild hypertension were enrolled in a lifestyle change program. Specifically, program participants initially had diastolic blood pressures in the 85-99 range (average 90.5). Systolic blood pressures averaged 140.4. Some of the subjects were put on a lifestyle change regimen, while the remaining ones were treated with a single blood pressure medication.

Lifestyle methods used included: weight loss, low salt diet, alcohol reduction, increased physical activity. After one year those in the lifestyle group alone: average systolic reduction 10.6, average diastolic reduction 8.1

Another study involved 73 men and women with high blood pressure who attended a three week live-in program at Weimar Institute in California. Their average age was 65. They adopted a series of lifestyle changes during this supervised program and reaped large reductions in blood pressure. Lifestyle changes included: abstinence from alcohol, tobacco, and coffee; total vegetarian diet; aerobic exercise. Average starting blood pressure: 150/81 average blood pressure at the end: 129/78. Two sets of changes were made simultaneously: changes in lifestyle and reductions in blood pressure medicine. However, reducing the medicine would normally produce an average increase in blood pressure, but the exact opposite occurred. Why? Because the lifestyle changes had such a powerful effect that they more than offset the blood pressure increase that would be caused by the reduction in medicine.

Another interesting result is that over half of the drop in blood pressure occurred in the first week. Blood pressure levels respond quickly to lifestyle changes.

What about salt intake?

There is much evidence that it significantly raises blood pressure.

For hypertensive patients, the greater the reduction in dietary salt, the greater the reduction in blood pressure. One basic cause of hypertension appears to be an inability of the kidney to eliminate an increased salt load. To excrete this excess salt, the body makes adjustments that boost the blood pressure, which then enables the kidney to eliminate the salt.

Salt consists of two elements-sodium and chloride; it is 40 percent sodium. However, the labeling of sodium content usually provides the necessary information: sodium and chloride typically are found in roughly equal amounts in foods. Thus by limiting the sodium intake, we generally limit the chloride intake as well.

A study involved 20 high blood pressure patients who were taking no medication, but reduced their previously high sodium intake to less than 3000 mg a day. Their average blood pressure was 161/101 after one year, average systolic blood pressure was lowered 19 and diastolic 14 points.

What about weight loss?

For individuals who are overweight, initiating a weight loss program can significantly lower the blood pressure. The blood pressure will usually drop as much as a low salt diet will drop it. The hypertensive patient does not need to reach optimum weight for a drop in blood pressure to occur. Just initiating a weight loss program and shedding about 5 pounds will bring the blood pressure down substantially in most cases. In order for the effect to be maintained, however, the individual needs to stay on the weight loss program until ideal weight is achieved. A simple four-step plan is prescribed for most of my overweight patients to achieve their desired weight.

1. No snacks. Drink only water between meals.
2. Eat a good breakfast and a moderate lunch. Eliminate the evening meal. If something "must" be eaten in the evening, whole fruit is all that is allowable.
3. Eliminate or at least greatly reduce refined sugar and free fats or fatty foods in the diet, while emphasizing foods high in fiber.
4. Daily moderate exercise for approximately 45 minutes a day.

What about Caffeine and Alcohol?

Studies show that caffeine affects blood pressure. One cup of coffee per day (or the equivalent in cola drinks) may raise the diastolic and systolic blood pressure five to six points. It follows that eliminating caffeinated drinks has the potential to lower blood pressure by the same amount. Caffeine not only raises resting blood pressure, but if consumed before or during exercise, it can raise blood pressure and heart rate considerably above the levels achieved during exercise alone. This could turn a healthy activity into an unhealthy one by increasing the risk of a significant cardiovascular event during exercise.

What is the effect of alcohol on blood pressure? Many people might not be aware that several drinks of alcohol per day raises blood pressure. I recommend eliminating alcohol entirely as part of a complete health program.

Are Foods High in Calcium are Beneficial?

Foods with a high calcium content can also significantly lower blood pressure. Over 6000 men and women with high blood pressure were classified as to their calcium intake. The result was that each gram of calcium consumed per day seems to lower the risk of high blood pressure by about 12 percent. Professor James Dwyer, who reported on the research at the American Heart Association annual meeting in November 1992, warns against taking large amounts of calcium supplements, however. "Instead," he said, "people should get calcium through their diets.green leafy vegetables are good sources of calcium."

Does Oatmeal Help?

A common breakfast food, oatmeal, has been found to reduce blood pressure. In one study, 850 people were categorized for the amount of oatmeal they consumed. One-bowl-per-day users had lower blood pressure and lower cholesterol. The effect was independent of age, weight, and intake of sodium, potassium, and alcohol.

The conclusion is that people who are trying to control their blood pressure naturally may get an unexpected benefit from eating a bowl of oatmeal each day. Thus oatmeal offers a double benefit for our hearts. It may also help to lower blood cholesterol levels because it is rich in water-soluble fiber. The information on blood pressure provides an additional endorsement for this versatile grain.

Smoking Increases Blood Pressure.

Smoking is another lifestyle factor that raises blood pressure. After smoking just one cigarette, both systolic and diastolic blood pressures can remain elevated for as long as 30 minutes. In fact, blood pressure can rise by 10 mm of mercury. Although a single cigarette does not seem to cause a lasting increase in blood pressure, many smokers have enough cigarettes in the day that they are continually raising their pressure during through most of their waking hours. Dr. Norman Kaplan, one of the world's foremost authorities on high blood pressure, points out that a typical pack-per-day smoker is elevating his blood pressure for most of the day.

Exercise

Aerobic exercise-exercise that calls into play the heart and lungs-significantly lowers blood pressure in hypertensive patients. In one study, eighteen sedentary individuals with high blood pressure completed a 16 week exercise program. During the program, they rode an exercise bicycle three days a week for about 45 minutes per day. They exercised at a moderate intensity (60 to 80 percent of their predicted maximum heart rate). After the four month program, the average systolic blood pressure fell 7 mm and the average diastolic pressure, 5 mm. The exercise program also helped to prevent their blood pressure from rising as high during exercise. Their average systolic blood pressure when exercising was 19 mm lower and diastolic 10 mm lower than before the program.

Overview:

Low salt intake is very important to improving the blood pressure.

Exercise may also help with this problem.

Stress reduction by turning our problems over to the only One who can take care of them will help.

Sunshine bathing may help to improve the blood pressure.

Smoking may raise the blood pressure and stopping may improve this.

Heavy alcohol intake may raise the blood pressure.

Weight loss in overweight individuals may be helpful.