- Diseases, Disorders & Conditions
What Causes High Blood Pressure?
What is blood pressure?
In order that the blood may course freely through the hollow tubes which we call arteries and veins, a certain force is necessary. This is mainly provided through the muscular contractions of the heart pump. With each beat of the heart a definite quantity of blood is forced into the arteries; and, as these tubes have elastic walls which recoil on the impact of the blood, the intermittency of the flow is counteracted, and a continuous circulation results. It is those driving forces maintaining the circulation which represent the blood-pressure, and this pressure is clearly dependent upon two factors, namely, the efficiency of the heart pump, and the caliber and elasticity of the arteries.
A rough estimation of the blood-pressure can be obtained by feeling the pulse at the wrist; but it is more customary nowadays for the doctor to gauge the pressure accurately by means of the "sphygmomanometer". This instrument consists of a hollow rubber armlet to which is attached a small hand pump and a clock manometer or mercury for registering the pressure within the armlet. When the doctor wishes to test the patient's blood-pressure, he straps the armlet round the upper arm, and then forces air into it until the pressure is such that the arm artery is blocked and the flow of blood stopped; this is shown by an inability to feel the pulse at the wrist. The force necessary to accomplish this (registered on the manometer) is equivalent to the force of the contracting heart muscle (systole) and elastic arteries. It is referred to as the systolic pressure.
In figures, the average systolic blood-pressure of a healthy adult is from 100 to 140; which means that it requires that pressure in millimeters of mercury to overcome the pressure produced by the heart and blood-vessels. Hard physical work and mental excitement tend temporarily to raise the figure, but
apart from these factors there may be considerable variation without departure from health. This fact must be emphasized, because a warning must be given against the tyranny of blood-pressure figures; there is undoubtedly a tendency for lay persons to become obsessed with their importance. Numerical records of blood-pressure are only to be evaluated in relation to the general health, mental as well as physical.
From the above facts it should be clear that the state of the blood-pressure reflects, or is a guide to, the efficiency of the heart and the tension of the arteries. For example, during shock, when the heart is acting feebly, the blood-pressure falls very low, and, in contrast, during violent exertion, when the heart is acting vigorously, the blood-pressure is high. Thus, too high and too low pressures are never diseases in themselves, though they may constitute evidence or symptoms of disease. To overcome the ill affects of those symptoms it is therefore necessary to investigate and seek to prevent their fundamental causes.
High Blood Pressure
There is a natural tendency for the blood-pressure to rise as old age approaches. This is due to the diminishing elasticity and gradual thickening of the arteries, which necessitate the heart beating more forcibly to overcome the increased resistance to the blood flow. Up to a point this rise is beneficial; but should the arteries become markedly hard and thick, the blood-pressure may rise to a dangerous degree. In consequence, the tension within the arteries may be so increased that they are unable to withstand the strain, and rupture when, if such a happening takes place in the brain, a " stroke " or an " apoplexy " results. The other risk is that the heart muscle, being unable to meet the excessive demands made upon it, weakens and fails. However, a moderately high blood-pressure in the elderly is no great cause for alarm, as the mode of life is generally restricted at this time of life; but a high pressure in middle-age leading to premature hardening of the arteries calls for urgent attention. This condition is also 100 referred to as hypertension or hyperpiesis. Most frequently the cause is neglect of the elemental laws of health. Over-eating, over-drinking, over-working, self-poisoning from a stagnant colon, defective kidneys, or focal infection in teeth, nose or throat, are fertile sources of hyperpiesis.
One other important cause of high blood-pressure may be mentioned. Independent of hardening of the arteries, an increased pressure may result from prolonged emotional disturbances- chiefly worry, anxiety, and hidden fears; these factors act by increasing the secretion of the adrenal glands, which diminishes the calibre of the arteries. A constant strain is imposed on these vessels, and this ultimately leads to their hardening- a condition which, as we have already seen, increases still further the blood-pressure.
Symptoms of High Blood Pressure
The onset of high blood-pressure is stealthy and silent, and it is not until some definite disorder of health arises that the condition is detected, unless periodic medical examination has been carried out and the blood-pressure systematically recorded. Herein lies the importance of blood-pressure measurements, for an increasing pressure is generally a sign that the arteries are becoming less pliable and elastic, and that an alteration in the habits of life is essential if good health is to be preserved. Established high blood-pressure is to be suspected if a middle-aged person complains of frequent headaches accompanied by sensations of giddiness, heart pain, easily induced fatigue and abdominal symptoms, such as flatulence and periodic attacks of vomiting.
Treatment of High Blood Pressure
In such a case much can be done to hinder the heightening of the pressure, and to counteract its ill effects. A drastic revision of the routine of life will probably be essential. The work output must be diminished, and all worry and mental strain avoided. Meat food must figure at a minimum in the dietary, but plenty of milk and water should be drunk. It is best to abstain from alcohol. Any source of self-poisoning must be eradicated. On this point, the doctor must be consulted. In particular the bowel function must work at its highest level of efficiency. Frequent warm baths, massage and gentle exercising are beneficial. Every means should be adopted to ensure sound and restful sleep at night. There should be no delay in seeking medical advice if any untoward symptom should arise. The intelligent observance of this advice will not only prevent any further increase in the blood-pressure, but will also add many useful years to life.
Low Blood Pressure
This condition occurs in certain forms of heart disease, and in states of exhaustion and debility which may arise from bloodlessness due to lack of sunshine and good food. It is a characteristic symptom in “Addison's Disease" (accompanied by a bronzed pigmentation of the skin), this disease being a result of a deficiency of secretion of the adrenal glands. In tuberculosis, the blood-pressure is often low, while in certain hereditarily predisposed persons it may fall considerably after meals or warm baths, and during spells of moist, warm weather, causing unpleasant reactions, such as lassitude, depression, sleeplessness and dyspepsia. A change of climate will often benefit these persons.
Sufferers from low blood-pressure, as in the case of high blood-pressure, must keep in mind that this condition is only a symptom, and that it is the underlying cause which must be detected and remedied.