GENERAL ARTICLES

Live Within Your Blood Pressure

W. W. BAUER June 15 1945
GENERAL ARTICLES

Live Within Your Blood Pressure

W. W. BAUER June 15 1945

Live Within Your Blood Pressure

"If you had no blood pressure you’d be dead," your doctor will tell you— If you have high blood pressure you may still be able to live a happy life

W. W. BAUER

WHAT HAPPENS when the doctor wraps the silk cuff around your arm and pumps it up until your fingers tingle? You know that he is taking your blood pressure, but what happens in the instrument he uses and what is the significance of his observation? What is passing through the doctor’s mind when he nods, looks wise, says “h’m, hm,” and when you ask him what your blood pressure is, answers with maddening nonchalance:

“That’s for me to know and you not to worry about.”

It is not uncommon for the middle-aged man or woman to walk into the office of a doctor and announce, “Doctor, I’ve got blood pressure.” To which the correct reply is, “Good. When you have no blood pressure you are dead.” What the patient usually means when he announces that he has blood pressure is that he has, or thinks he has, high blood pressure. Low blood pressure is not popular among topics for bridge table conversation.

Can a person be cured of high blood pressure? That answer is not a simple yes or no. Many persons have temporary high blood pressure from which they recover. However, when blood pressure has reached permanently high levels, cure is not possible in the sense of a permanent return to normal.

But, large percentages of these persons can, nevertheless, live long lives, and live them very successfully by adjusting their lives to their blood pressure. Every doctor has numerous patients whose blood pressure is high, sometimes at dangerous levels. Yet these patients can often live a long time if they do everything in moderation, cultivate good control of the temper, and learn to take things as they come.

As one philosophic doctor expressed it, he tries to change the attitude of his patients from, “What the hell!” to “Oh, well!”

The man in the street shows a very good idea of what blood pressure is all about when he classifies life’s irritations, big or little, as “bad for the blood pressure.” In this he is quite scientific, since laboratory experiments have shown that rage, fear, joy, surprise, or any other overwhelming emotion affect the blood pressure one way or another. In the combative type of individual the blood pressure rises; in the human mouse the blood pressure may fall to the point of weakness or fainting.

The body contains about five or six quarts of blood, enclosed in a hollow system of which the principal parts are the heart; the treelike system of arteries and their branches, of which the smallest are called arterioles; a tremendous mesh of fine capillary vessels pervading every organ and tissue, and a collecting or return network of veins originating in the capillaries and joining together to make larger and larger veins until at last the largest veins join to form one which connects with the heart. This round-trip system is necessary to bring blood to the cells of the living body.

The heart is the principal source of circulatory energy, but it has two principal types of assistance; the elasticity of the arteries and the pressure of muscle on veins, which helps the return flow of blood and tissue fluids toward the heart.

When the heart pumps a volume of blood into the arteries these elastic vessels dilate somewhat. When the heart relaxes, the arteries, through their elastic qualities, maintain a pressure, not as high as when the heart contracts, but considerably above the zero pressure which would result if the arteries were not elastic. The greatest elasticity is in the smaller arteries, or arterioles, which deliver the blood to the capillaries in a smooth, steady, even flow.

The contraction of the heart is known as systole and the high point of blood pressure which accompanies this contraction is called “systolic.” The relaxation of the heart is called diastole and the corresponding low point in blood pressure is called “diastolic.” If the diastolic pressure is

subtracted from the systolic we get the blood pressure range, which is also known as pulse pressure. You can feel the change in arterial pressure by putting your fingers over any artery near the surface, as at the wrist, in front of the ear, or in the throat.

The first blood pressure observations are credited to the Rev. Stephen Hales, a clergyman of Teddington, England, who in 1710 cut the thigh artery of a mare and connected it to a glass tube nine feet tall. The blood rose in the tube to a height of eight feet, three

inches above the animal’s heart. After him other experiments along the same lines were performed on animals, which had to be killed after the observations.

In 1856 Faivre did to a man exactly what Hales had done to the mare a century and a half earlier. He inserted a tube in the femoral artery of a man undergoing a leg amputation and measured the blood pressure against a column of mercury. The mercury was raised above atmospheric pressure level by 120 millimetres (not quite five inches), a figure which represents the most usual systolic blood pressure.

As everyone who has ever had his blood pressure taken knows, your doctor need not cut an artery to take an observation. The instrument he uses, a sphygmomanometer, is designed on the principle that blood pressure can be measured indirectly by applying and measuring air pressure on the outside of the body.

When the doctor makes an observation he wraps a hollow rubber cuff around the upper arm. Then he pumps the cuif up to a pressure higher than he expects the blood pressure to be. The cuff constricts the arm and shuts off the pulse at the wrist and the sound of it at the elbow. The doctor gradually lets the air out of the cuff until he first feels the pulse or hears the sound at the elbow, and at the same time measures the air pressure in the cuff by means of a mercury column or dial attached to it. This is the point at which blood pressure just overcomes air pressure and is the high point, or systolic blood pressure. Still continuing to let the air out slowly, he observes the point at which the pulse first reaches its maximum; this coincides with the greatest range of fluctuation in the mercury column or dial synchronous with the pulse beat and also with characteristic modifications of the sound of the pulse beat heard at the elbow. This is where air pressure equals the lowest pressure in the arteries and is regarded as the diastolic pressure.

Normal blood pressure is too variable to be reduced to specific figures. It is one level for you; another for me; it stands at different heights according to whether you are standing, running, sitting, lying; it varies with fear, rage, joy, despair. The usual figure is 120 systolic and 80 diastolic, but these are only averages. The one most important fact to remember about blood pressure is that it is extremely variable. Only repeated observations can establish the true level of an individual’s habitual blood pressure, normal or otherwise. There is no universal normal.

Blood pressure is due primarily to forceful ejection of blood by the heart into an elastic system of arteries. It is generally held that blood pressure is controlled principally by the arterioles. When these small elastic arteries are narrowed they offer increased resistance to the flow of blood; when they are relaxed they offer less. Temporarily they constrict in response to stimuli already mentioned; if too often stimulated they may lose elasticity and offer a permanent resistance, or dam, to blood flow, thus increasing blood pressure permanently. Blood pressure is probably influenced by hereditary factors, such as the capacity of the heart and arterial systems; some persons have apparently spacious and others less spacious arterial systems.

The blood vessels are intimately related to the nervous system. The arterioles react readily to emotional stimuli, such as fear, rage, joy, chronic apprehension, worry and physical and mental shock. Reactions differ. In some individuals an emotional stimulus causes constriction of the arterioles and raised blood pressure; in others, the same

stimulus relaxes

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Live Within Your Blood Pressure

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the arterioles, with consequent lowering of blood pressure, weakness, dizziness and possibly fainting.

The variability of blood pressure is well illustrated by the experience of persons whose blood pressure is taken when they are apprehensive. Examinations for military service, visits to the doctor when there may be fear of serious disease, examinations for civil service, life insurance, or any other situations involving personal interests important to the patient may result in nervous tension which produces a high reading. Doctors understand this; they give such patients an opportunity to be reassured, to accustom themselves to the doctor, to their surroundings and their general situation, and then take the patient’s blojd pressure again. Often the second reading is perfectly satisfactory.

As long as blood pressure fluctuates it may be considered normal, even if its customary level is a bit above 120 over 80. It is only when it becomes fixed at a high or low level that it is abnormal.

There have been many conflicting theories as to the cause of high blood pressure. Dietary articles, especially meat and salt, have been blamed, apparently without good reason. The hustle-bustle of modern living is sometimes held to be the cause of blood pressure elevations. Glandular conditions, especially those of the thyroid, often raise the blood pressure; a severe disease of the adrenal glands, called Addison’s disease, is one of the causes of low blood pressure. Tobacco, because of its deteriorating effect upon the arteries in some persons, has a worse history with respect to high blood pressure than has alcohol moderately used, which some doctors believe is actually beneficial to high-strung elderly persons because of its relaxing action upon the circulation.

High blood pressure is closely related to certain forms of heart disease but it is probable that the high blood pressure causes the heart disease and not vice versa. It is also related to certain types of Bright’s disease (kidney disease; nephritis); in this case a vicious circle is established, each condition reacting unfavorably upon the other and both upon the heart, to the great detriment of the patient. Chronic, repeated infections may or may not have a causative relationship to high blood pressure.

High blood pressure at relatively early ages has been observed in several generations of the same family. Perhaps that is due to the fact that some individuals are born with smaller and less spacious arterial trees than others. Or it may be explained on the basis of greater nervous susceptibility to stimuli which react upon the blood vessels. Heredity seems to be of considerable importance. Persons with a history of high blood pressure in the family will find it worth while to pay reasonable attention to the development of such a condition in themselves.

It is sometimes possible by tests to ascertain in a relatively young individual whether he might be susceptible to higher blood pressure as he grows older. In a typical series of experiments the subjects lay horizontally on beds close to which vessels of ice water were placed. Preliminary blood pressure observations were made; then the patient’s arm was plunged suddenly into ice water and the rise in blood pressure noted. Individuals with a family history of high blood pressure,

especially when this had occurred at early ages, reacted more sharply to this stimulus than did others.

The Journal of the American Medical Association in 1940 reported the records of 1,522 patients. Half of these were re-examined 10 years after their first blood pressure readings and about the same number 20 years afterward. In the original group 13.2% had high blood pressure. Among those examined after 10 years the percentage was 23.5. But note! Among patients who originally had high blood pressure an elevation of blood pressure was found in practically 60% after 10 years and in 85% after 20 years. Thus evidence accumulates that even temporary increases in blood pressure due to emotional stress, when exaggerated, may indicate danger from permanent high blood pressure later in life.

Racial blood pressure differences, particularly where races differ markedly in temperament, have been investigated. A group of Chinese living in western Canada were examined with respect to their blood pressure. Blood pressure is known to be low among the Chinese who live in ! China, but of the Chinese residents of Canada, 11% had high blood pressure. I

Worry a Big Factor

We will probably have to part with ¡ our favorite idea that stress and strain ! of modern living is bad for the blood pressure. It is true that we work long I hours, play too hard, drink too hard, smoke too much, eat too much, and | otherwise conduct ourselves like human beings. But if we stop to compare our ^ lot with that of our Indian-fighting i ancestors, we shall have to conclude ' that life today is not harder than it j was in the pioneer days. It is, and we may as well admit it, definitely easier. ;

One thing we may probably claim, ! though, is that worry is a characteristic j of the modern age. Worry, suppressed fears and nervous tension are more to be feared as causes of high blood pressure than any other factor in modern living.

These tensions are generally attributed to business worries and therefore more likely to affect men than women. On the other hand, it is just as possible to develop high blood pressure, both figuratively and literally, in pursuits more common to women, such as competition for social prestige, excessive devotion to “causes” and worry over children or other family situations. Unhappy home situations may obviously affect either sex. Women normally have lower blood prèssure than men and often react less violently to stimuli causing high blood pressure, because of a less aggressive organization of the organism as a whole. However, high blood pressure due to pregnancy may become permanent, and suppressed reactions may also cause a tendency to raised pressure. Statistics are unsatisfactory. Most observers report no preponderance of high blood pressure in either sex; a few say it is more common in women.

Everyone wants to know how high blood pressure can be cured. Its relationship to interference with kidney circulation suggested production of experimental high blood pressure in animals by partially clamping the arteries leading to the kidneys. Such artificial high blood pressure was then treated in various ways, including the removal of the kidney nerve and supply and operations which cut the nerve connections between the arteries and the central nervous system.

These operations, successful in some instances of spontaneous high blood pressure in man, failed when they were used for the treatment of experimental high blood pressure in animals. In

man, high blood pressure due to disease of one kidney may occur. The Canadian Medical Association Journal reports a case of a man who developed a very severe malignant high blood pressure after removal of a stone from his kidney; he was promptly and completely relieved by removing that kidney. Removal of a single diseased kidney has relieved high blood pressure in a number of cases, but has also failed to relieve it in others, probably because in these latter the remaining kidney was not normal.

Experimental production of inflammations around the kidney, as done by Page of Indianapolis, has also produced artificial high blood pressure. Page holds that renin, a chemical substance liberated by the kidneys, elevates the blood pressure and he does not regard the nervous system as the primary cause of high blood pressure, though he admits that it certainly plays a part. The view of Page and his co-workers at the Lilly Laboratories is that reduction of the circulation in the kidney raises the blood pressure very high. On the basis of this theory treatment has been instituted, but Page warns that this is still in the experimental stage.

Among the most widely publicized of recent treatments for high blood pressure has been the so-called rice diet, which consists simply of rigidly adhering, for a long time, to a monotonous diet composed almost entirely of rice. It meets with lack of enthusiasm, not to say unpopularity. The rice diet consists basically of rice, plus sugar, fruit, fruit juices, vitamins and iron. Kempner, at Duke University School of Medicine, reports on the giving of a rice diet to 150 patients, many of them seriously ill. They were under treatment from four days to 30 months. The treatment was ineffective in 41 of the 150 patients, including 18 who were critically ill when the diet was started and who died within three weeks of starting it. In all the others the diet was beneficial. The principle of the rice diet is to substitute vegetable protein, derived from rice and fruits, for animal protein, which injured kidneys are no longer able to handle. This theory should not be confused with the common belief that animal protein (meat) causes high blood pressure and kidney damage.

Symptomatic treatment for high blood pressure consists in enabling the patient to live with his condition as best he can. It is not usually possible to reduce high blood pressure greatly and often it is not desirable to do so, because the patient feels better with a high blood pressure to which he is adjusted than with a “normal” pressure to which he is no longer accus-

tomed. Diet need seldom be modified much except in the direction of moderation. No foods need usually be eliminated but total intake needs to be limited. Weight must often be reduced. Sudden exertion or prolonged exertion must be avoided. Fatigue is harmful. Freedom from responsibility or, at least, the minimizing of worry is desirable. Moderation in all things is the watchword. Resort to the more severe methods, such as extensive surgery on the nervous system, can often be avoided.

Neglected high blood pressure results in injury to the heart and to the kidneys, so that one or the other fails. It also creates danger of rupture of the smaller arteries, since it is often accompanied by hardening and deterioration of these vessels with loss of elasticity and weakening. Such a rupture, with attendant hemorrhage, is called apoplexy or, in the vernacular, “stroke.” There is a popular superstition that the third stroke is always fatal. This is not necessarily true. Often the first stroke is fatal; some persons, on the other hand, suffer numerous light strokes and live. Many persons live for considerable time with high blood pressure and do not know about it until it is discovered in the course of life insurance or other medical examinations.

The best approach to the blood pressure problem today is prevention. Continuous relationship should be maintained with a physician, who will supervise the general health, observe the trend of the patient’s blood pressure and keep at a minimum the known or possible causes of unfavorable changes in the arteries, kidneys, heart and nervous system, and take prompt countermeasures when necessary. For those who have already an established high blood pressure it is almost always possible for the doctor, with appropriate co-operation from the patient, to adjust that individual’s level of activity to a point where he will not further injure his health. This may mean temporary complete rest in bed, but usually before long it is possible to resume a limited program of activities.

Many thousands of persons are now living with reasonable contentment even though their blood pressure is considerably above normal. High blood pressure, like many another medical condition for which there is no positive cure, can nevertheless be treated with considerable success if doctor and patient together will apply the knowledge that we have, pending the development of new methods. The recent history of medical progress gives great hope that new solutions for the blood pressure problem will soon be at hand.