The mechanism by which blood pressure is elevated in essential hypertension is well known. There exists throughout the body an increased resistance offered to the flow of blood through arterioles. In the early stages of hypertension this constriction of arterioles is easily
reversible and during sleep or as a result of sedation the blood pressure returns to normal, indicating relaxation of arterioles. There is little or no reason to believe that organic changes in arterioles (excepting perhaps those in the kidneys) precede hypertension or
contribute to development of it in the early stages of this condition.
It is now well known that hypertension of man indistinguishable from essential hypertension may be produced by unilateral renal lesions and that when a diseased kidney is removed surgically the blood pressure may return to normal. Barker and Walters have demonstrated this in an excellent manner. Unfortunately, such renal lesions are found very unusually in hypertension.
Almost 95 per cent of patients with hypertension have a family history of cardiovascular disease. Study shows that the incidence of elevated blood pressure in families in which both parents had normal blood pressure was only 3 per cent. If one parent had hypertension, the incidence of hypertension among the children was 28 percent and when both parents had hypertension the respective figure was 45 per cent. The hereditary factor is well shown by the study of Hines, which indicates that the substratum of hypertension is inherited and is apparent before hypertension develops.
Since hypertension is produced by increased resistance offered to the flow of blood through the arterioles, the specific need in medical treatment is a preparation which will restore arteriolar resistance to normal and which will not produce harmful or unpleasant side effects. Unfortunately, such a preparation is not available now.
Rest and the reduction of nervous stresses and strains are adviseable in the treatment of many patients who have essential hypertension. In general, it is adviseable for patients who have hypertension to obtainnine hours of rest in bed at night, to lie down for an hour an hour and a half in the middle of the day. to take vacations frequently, to acquire a calm. philosophic outlook on life and to avoid nervous stresses and strains.
Individuals who are overweight should reduce, for obesity throws an additional strain on the heart by increasing the work that it must do and as a result of deposition of fat in cardiac muscles and around the heart. Restriction of alcohol and coffee is not imperative unless they serve as stimulants. Indeed alcohol reduces it temporarily. Smoking greatly increases the blood pressure of many patients who have hypertension, and if this can be demonstrated by having the patient smoke after his blood pressure has reached a basal value, it is well to consider sharp restriction or complete elimination of smoking.
The conclusion relative to failure of reduction of blood pressure by medical means is supported by the opinion of almost all those who treat patients who have high blood pressure under controlled conditions, by the high mortality caused by hypertension, and by the number of physicians who consult other physicians or refer their patients to other physicians because the physician’s own medical treatment has been unsuccessful.
This medical journal of internal medicine is written by Edgar V. Allen, Division of Medicine, Mayo Clinic, Rochester, Minnesota. If you need to read full article, so you can download it here.
