High blood pressure is believed to be caused by:

(i) Heredity

Studies conducted in various countries indicate that with one percent being hypertensive there are 25 percent chances of the offspring getting afflicted with it while if both the parents suffer this problem the 90% progeny is likely to be suffering from it.



The medical theories seem to agree that generic is the most potent factor for causing hypertension, although it is not usually manifested until middle age.

(ii) Environmental Stress and Personality

Environmental set up often leaves a lasting impression upon one's psyche and we develop our stress. For stance, a person bred and brought up in a traditional house would be aghast seeing his young son taking liberties with his girl friend in his presence, while the reaction to and the stress of the spectacle won't be that over powering to a west-oriented person. A person's emotional make-up and response to tension and stress has often been cited as a predisposing factor to hypertension. Strong emotions such as fear anxiety, anger or painful stimuli can raise an individual's blood pressure. But the pressure usually goes back to normal when the stress is removed. In some individuals, however, the pressure does not go down when the tension ends. In such persons the blood pressure is being continuously raised in their daily lives and eventually may remain at a higher level.

(iii) High Salt Intake

Having remained in the centre of a heated debate for decades it has now been established that high salt intake has a definite bearing upon the person's developing high BP. The examples of Japan and Korea are cited as an example to prove this point. There the salt intake is traditionally high due to a diet of meat and fish preserved in salt. Consequently high blood pressure is the natural outcome. To further strengthen this observations it may be noted that there is a small, isolated community in Japan where salt intake is low and these inhabitants show average BP. Medically it is proved that high salt diet suck up water from the body to make the blood more heavy which results into high BP. Also, it has been observed that some primitives who eat very little salt as they mostly eat their preys raw, their BP remains perpetually low.

(iv) Overweight

Again there is no conclusive proof that only overweight persons develop hypertensions but it has been clinically observed that overweight persons are more prove to become hypertensive. The statistical analysis conducted by various insurance companies aver that persons who were overweight often showed blood pressure on the higher side and hence, were not considered good insurance risks.

(v) Age

The most vulnerable age for getting afflicted with hypertension is between the age of 45 to 60. No particular reason has been found why it is more marked in this age group barring the fact that the elasticity of the arteries gets reduced with the advanced age. It is also possible that this condition is detected more frequently in the older generations, as outward symptoms of high BP take a long time to appear. However, since not all older persons have high blood pressure, these conditions can't be held to be the final cause.

Generally men are more prone to becoming the victims of high BP. Incidence of hypertension in them increases till the age of 50 and then levels off. However, in women's case the incidence of high BP increases continuously with age.(vi) Hardening of Arteries & Blood Pressure

If neglected for long the hardening of arteries can lead to blood pressure and may cause other serious ailments as well.

(vii) Other Reasons

In other causes the prominent ones are alcohol intake and smoking. There is some evidence to indicate that heavy drinking may cause or aggravate high BP. Although alcohol is not a direct cause of coronary heart disease or stroke, there is no doubt that heavy drinkers are at high risk. Also, since obesity is the frequent result in case of the heavy drinkers-owing to high caloric content of alcohol and since alcohol also makes one eat more-indirectly alcohol does play a role in causing high BP. The worst part is that alcohol makes drug treatment of high BP more difficult and less effective. Certain sedatives which help lower the BP are not given in the case of the alcoholic patient and hence the treatment becomes more cumbersome.

Nicotine found in cigarettes stimulates the production of 'pitressen' (a chemical) which may constrict coronary arteries, thus increasing the BP. Continued smoking also raises blood cholesterol as well as fatty acids which further predispose an individual to arteriosclerosis. Smoking cigarettes, 'bid is' or even chewing tobacco are common practices in our country. All of these vile habits contribute to increasing blood pressure of the individual which in turn enhance work-load of the heart.

At times contraceptive pills increase blood pressure in the women users. These pills contain harmones-oestrogen and progesterone. Those women who take this pill for longer duration have their BP increased to alarming limits.

Weakness of kidney could also be a potent cause for making the individual hypertensive. Besides alcohol, even the excessive intake of tea and coffee may also irritate the fine structure of the kidneys and ultimately disturb the blood pressure.

Primary Causes

Thus far we have discussed the causes that induce high HP. However, there are some causes, called primary causes which are due to the inbuilt trouble in the body to identify these, certain cases of high HP needs to be examined thoroughly and clinically by the laboratory, X-rays electro cardiograms (ECG), X-ray examination of aorta or autography, renal arteriography and even kidney biopsy. Only those persons should go for such tests when the causes in the induced category like age, hereditary etc yield no clue for the diagnosis of hypertensions.

(i) Congenital Narrowing of the Aorta

This results in high blood pressure in the upper part of the body and arms, and persistently normal or rather low blood pressure in the legs. It is, as the name suggests, due to a congenital defect in a short segment of the aorta.

(ii) Renal Defects Leading to Hypertensions

As well as know, the kidney requires normal blood flow. The slightest abnormality in the flow may cause high HP. The doctors attempting to diagnose the cause of hypertension must always examine the renal system of their patient. Even an obscure kidney defect may give rise to this problem. In case the defect needs transplantation, of the kidney that should be resorted to for without kidney trouble being cured the high HP syndrome is likely to remain incurable.

Another factor in this category is the Renal Artery Stenosis or the abnormal narrowing of arteries supplying blood to the kidneys. This may be congenital or acquired conditions which cause hypertensions. This defect may be corrected either surgically or by medicine.
Renal stones-excessive calcium deposit called calculus¬in the kidney also causes distruction of renal tissues and high blood pressure. But these may be missed and their presence revealed for the first time by the patient's history of renal colic or pain or the appearance of small stones through the urethra. These stones can be removed with the help of medicines or surgically.

Another cause is Polycystic Disease of the kidneys. It is an inherited disorder in which the substance of both kidneys is largely replaced by numerous cysts. This disease is not evident in the childhood which raises its head between 40 or 50 years as an inherent cause of hypertension. Enlarged¬ kidney or chronic kidney failure at an advanced stage are one of its symptoms. .

There is another very important cause of high blood pressure related with kidney trouble. It is called Pyelonephnitis which is the bacterial infection of kidney substance. In acute stage the patient has pain in loins, a high temperature and shivering fits. Antibiotic treatment following a complete urological investigation is essential to cure and prevent its recurrence.
Also, when the kidneys are intruded by a starch like substance called amyloid the conditions lead to hypertension. Renal biopsy is employed to diagnose the cause and the complication is controlled by medicine.

(iii) Inflammation of the walls of the Arteries

This disease is called Polyarteritis. It is a disease of unknown cause thus far but hypertension is one of its major manifestations. This inflammation is generally suppressed by the drugs called corticosteroid like prednisolene.