What you need to know about high blood pressure: many factors you can control can contribute to high blood pressure.

In the United States about one in three adults has elevated blood pressure. Many people do not know that they have a problem, because frequently it can exist for years without any symptoms. It is, however, a problem that needs to be taken seriously, because it can, without warning, cause serious disease and even death.

Unless treated, high blood pressure can result in stroke, heart attack, kidney disease, and even blindness as a result of hemorrhage in the retina of the eye. Persons with high blood pressure have eight times the risk of stroke and three times the risk of heart attack compared to those with normal blood pressure.

Arterial blood pressure is measured against a column of mercury and is recorded in millimeters. It reaches its maximum following the emptying of the left ventricle into the aorta immediately after it contracts. This is identified as the "systolic" pressure. It drops during the time the heart is filling with blood and reaches its minimum just before a succeeding ventricular contraction. This is identified as the "diastolic" pressure. For these reasons, the pressure is usually recorded as two figures, such as 120 (systolic) and 80 (diastolic)--120/80.

In general, the lower the blood pressure, the better. Those having lower pressures live longer than those with higher levels. The incidence of heart attacks and strokes increases as the blood pressure increases.

There is no point at which the risk suddenly increases greatly. Therefore, what is termed normal or abnormal are arbitrary divisions. A reading of 120/80 is considered to be normal. However, lower blood pressures such as 100/60 may result in longer life. Normal is considered in adults to be up to 140/90. As mentioned, this is an arbitrary cutoff point. Between 140 and 160 systolic and between 90 and 95 diastolic is termed by physicians as borderline. Anything at 160 or above systolic and 95 or above diastolic is considered to be indicative of hypertension.

Since blood pressures fluctuate quite widely, a diagnosis of hypertension is not made unless several readings are elevated when taken at various intervals. Slight emotional stresses may elevate the systolic pressure considerably within a few minutes. The diastolic pressure is not elevated to as great an extent under such circumstances. For this reason a physician finding an elevated diastolic pressure considers it to be more serious than an elevated systolic pressure, if it is the first time he or she has taken the blood pressure. If the systolic pressure is consistently elevated, however, it is as dangerous as an elevated diastolic pressure.

In about 90 percent of the cases, a physician makes a diagnosis of "primary" or "essential" hypertension. This means the cause of the high blood pressure is not known. If the cause is known, the condition is termed "secondary" hypertension. That means the high blood pressure is secondary to some specific condition such as adrenal tumor or renal artery constriction. Some of these causes are correctable.

Some specialists in hypertension believe that the cause may be found in an additional 10 percent or more of the cases if adequate tests are done. These tests may be expensive, but may well be worth the time and money. University hospitals usually employ someone who specializes in the diagnosis and treatment of hypertension.

Factors You Can Control

Many controllable factors contribute to high blood pressure. Should you have any of these problems, be sure to take the proper measures to control them.

Obesity. If you are overweight, that factor alone may elevate your blood pressure; you should reduce your weight immediately. Reducing weight has been the biggest single factor (greater than even a low-salt diet) in lowering blood pressure.

The proper way to do this is very simple: exercise more and eat less. Exercise has not been shown to be of great benefit in losing weight, but has been shown to be of great benefit in keeping the pounds off and not regaining the weight. If you find reducing to be difficult, here are some hints that may help you.

Do not snack. This is all that most overweight people need to know to control their weight. By stopping your between-meal snacks, you can reduce your daily intake by several hundred calories.

Reduce the use of empty and refined calories. There are four basic food types that contain calories of this kind:

* Visible fats. These are fats such as cooking oil, margarine, and similar fats that are visible in or on your food.

* Sugar. Eliminate foods that are high in sugar, such as desserts, soft drinks, ice cream, doughnuts, and other between-meal sweets.

* Refined cereals. Cooked cereals are usually better than commercial dry cereals. If you like dry cereals, use products such as shredded wheat, which are whole-grain and which do not have added sugar.

* Alcohol. Drinking alcoholic beverages can result in a surprisingly high intake of empty calories. It has another side effect--for those on a diet, alcohol can weaken the willpower and result in the breakdown of any dietary program you've set for yourself.

Reduce the use of foods high in saturated fats and cholesterol, such as meat, whole milk and cheese, hard shortenings, and eggs. Butter, of course, is high in both cholesterol and saturated fat and from the heart attack standpoint is much worse than margarine.

Eat a good breakfast. If it is necessary to skip a meal in order to lose weight, skip supper rather than breakfast. Breakfast should be considered the most important meal of the day. Two studies show that the same number of calories taken in the morning do not put on as many pounds as when taken in the evening. Although some have promoted many small meals a day rather than a few large ones, a scientific study now shows it takes 40 more calories per day to digest the larger meals than the smaller ones. Therefore, two larger meals would be better than six smaller ones even when they have the same number of calories.

Use foods high in fiber and water content such as greens, carrots, string beans, and so forth, which will fill you up without putting on much weight.

These are called low-caloric-density foods. It has been demonstrated that on a high-fiber diet one is satisfied with only 50 percent as many calories. A high-fiber diet usually means a lowfat diet, and a low-fiber diet usually means a high-fat diet. Those using meat regularly have twice the risk of obesity than vegetarians have. This is because meat is without fiber and is high in fat content.

If all else fails, fast one or two days a week. Do this under a doctor's supervision, because it shouldn't be done by diabetics or hypoglycemics and perhaps under some other medical situations.

Exercise. Exercise helps some individuals lower their blood pressure. This is true even of people who are not overweight or under stress. The type of exercise is important, however, since some exercises are more useful than others in lowering blood pressure. Calisthenics and muscle-building exercises, for example, may be good for flexibility, but are not as useful in treating the problem of hypertension.

To lower blood pressure, one needs continuous exercise of at least 20 minutes' duration. Probably the best exercise is walking. Work up to the 20 or 30 minutes gradually and as you become used to it, increase the speed and the distance that you cover in that 20 to 30 minutes each day. If you are quite overweight, increase your exercise very gradually. Before doing any vigorous exercise, have your physician do an electrocardiogram/stress test to be sure your heart can take it.

Stress And Emotion. Stress and tension may also elevate blood pressure. A good exercise program helps relieve stress. Also, take regular vacations, stop bringing your work home in the evenings, and consciously try to relax several times a day. Noise of any type may increase tension and stress. Keep the TV and radio off except for the few good, non-tension-producing programs. Trusting in God's care for you should help you not worry over the many problems of the day.

Salt. It may be necessary to reduce sodium in your diet in order to get your blood pressure under control. Sodium chloride (salt) is worse than sodium by itself. Salt is the source of most of our sodium. The average American uses at least two teaspoons of salt a day, two thirds of which comes from packaged foods purchased rather than from the saltshaker. In northern Honshu in Japan the average salt use was approximately seven teaspoons a day, and 40 percent of the adult population had high blood pressure.

The body needs only about a tenth to an eighth of a teaspoon of salt a day. It may be well to avoid salty foods such as salted peanuts, olives, soy sauce, and salt from the saltshaker at the table. But more important, switch from all those packaged foods to planning meals from the fresh produce in the market.

Diet. Studies show that vegetarians have less tendency to high blood pressure. Some researchers suggest that reducing or eliminating the use of meat in the diet may be the best therapeutic approach to high blood pressure. Although atherosclerosis may or may not be the cause of your high blood pressure, the two are frequently associated together. High blood pressure accentuates the atherosclerotic process, and so as a rule, one who has had hypertension consistently over an extended period of time probably has developed some atherosclerosis.

For several reasons, then, it is well to be on a diet that tends to prevent atherosclerosis--in other words, a diet that is low in saturated fats and cholesterol. Since meats contain high quantities of these, a vegetarian diet is to be recommended. (By the way, there is as much cholesterol in chicken as in beef.)

The total amount of fat in the diet, especially animal fat, should be lowered for most Americans. We should switch to nonfat milk instead of using whole or low-fat milk. Reduce, or better yet, eliminate the use of egg yolks.

With equal salt intakes, populations that take in more potassium have less of a problem with hypertension. Potassium dulls the effect of sodium in elevating blood pressure in rats. A sodium-potassium ratio of 1:2 prevents hypertension. Salt increases blood pressure in salt-sensitive rats, but with added potassium the blood pressure does not increase.

Blacks have a greater problem with hypertension than do Whites. The urinary sodium-to-potassium ratio is much higher in Blacks than in Whites. The Kempner rice-fruit diet (cooked without salt) was used for lowering blood pressure before diuretics were available. The sodium-potassium ratio of that diet was 1:20. The average American diet has a ratio of 1.5:1. Doesn't this tell us something? Use more fruits. Use them as staples, not just as desserts.

Some have shown that higher calcium intake results in lower blood pressure. However, such studies are not consistent with the world epidemiological data. It is in countries in which milk (high in calcium) is not drunk that populations with the lower blood pressures are often found. The suggestive evidence that calcium is a factor is still being left at that point--it is still only suggestive. Caffeine has been shown in a number of studies to elevate blood pressure, and so to be on the safe side, avoid coffee and tea.

Tobacco. Smokers are more apt to have hypertension. If you smoke and have high blood pressure, you certainly need to kick the habit. If you have trouble doing so, call the Seventh-day Adventist Church in your area and find out when they will have their next Breathe-Free program for smoking cessation. This program has been successful for many. More people have kicked the habit through the programs of the Seventh-day Adventists than any other group or type of smoking-cessation program.

Alcohol. Most people are confused because of the mixed messages they are getting on the use of alcohol. It has been promoted as something that lowers heart attack risk. But it is known that motor vehicle accidents, homicides, cancers, and even elevated systolic blood pressures are caused by the use of alcohol even when taken in moderate amounts.

The World Health Organization, after looking at all the data, does "not recommend that alcohol be ingested." The National Academy of Sciences also had a scientific committee study the matter, and concluded: "This committee does not recommend alcohol consumption." The best advice today is to stay away from alcohol.

Estrogens, commonly used by menopausal women, and birth-control pills do cause high blood pressure in some individuals. If the high blood pressure came on after you started using these pills, you should suspect that this may be the cause. Consult your doctor.

Tyramine. Some people are sensitive to tyramine, a substance commonly found in cheese and red wine. This may result in high blood pressure. This is an easily treatable condition. But since there are so many possible causative factors for high blood pressure, it is important to see a physician and attempt to determine the cause.

What Else Can You Do?

It would be well to purchase a sphygmomanometer and stethoscope and learn how to take a blood pressure. If a family member has the problem, a regular monitoring of blood pressure can be done each day without going to the doctor's office. This would help your doctor determine just what medicines are needed and how much to prescribe.

The treatment for mild hypertension is initially by rational therapy--weight control, limiting salt intake, proper exercise, learning to cope with stress, eliminating use of alcohol, etc. Some studies show that as many as 70 percent of hypertensives may lower their blood pressures significantly through these natural physiological means. If this method does not work, however, medications will be suggested. If your doctor prescribes medications, remember they will do you no good unless taken as the doctor says they should be taken.

New information tells us that high blood insulin often occurs with those who have hypertension, those with heart attacks, prediabetics, and the obese. This is a common factor that ties these diseases together. Most medications prescribed for hypertension actually aggravate the hyperinsulinemia. It has been stated that stroke risk in hypertensives may not be lowered much by lowering the blood pressure unless the blood insulin level is also lowered. There is no good medication to lower blood insulin. However, it is known that exercise, weight reduction, and limiting use of sugar may be helpful in lowering blood insulin. Therefore, following good health habits is important whether or not you are on medications for your blood pressure.

Summary

1. Get your blood pressure checked regularly. If it is high, follow your doctor's instructions carefully. 2. If you are overweight, get your weight down. Getting it down even a little helps to lower the blood pressure. 3. Eat a good diet, limit salt to one teaspoon a day, avoid high-cholesterol and saturated-fat foods, and use more fruits and vegetables. 4. Substitute good health habits for bad ones. Stop the use of tobacco, alcohol, tea, and coffee. 5. Learn how to cope with stress. 6. Develop a regular exercise program. 7. If medications are prescribed, take them regularly.

J. A. Scharffenberg is a medical nutritionist. He is adjunct professor of nutrition at Loma Linda University. He is assistant director for health promotion for the world church of Seventh-day Adventists and in this capacity travels extensively throughout the world. While at Loma Linda University be developed the "Heartbeat" coronary risk evaluation program, in which more than 100,000 people have participated. He is a graduate of Harvard's School of Public Health, was director of the International Nutrition Research Foundation, was on the secretariat of the Interdepartmental Committee on Nutrition for National Defense while at the National Institutes of Health, and has been a consultant for the National Centers for Disease Control.