What Causes High Blood Pressure?

In 85-90% of the cases of high blood pressure (hypertension), no specific underlying cause for the raised blood pressure is found even after thorough evaluation. Such cases are referred to as essential hypertension or primary hypertension. There are certain risk factors, which increases the chance of either having the primary hypertension or developing it in the future.

The remaining 10-15% of the cases of raised blood pressure are due to a specific disease that secondarily results in elevation of the blood pressure. Such cases are referred to as secondary hypertension. There are numerous diseases which can result in raised blood pressure. However, only the most common causes of secondary hypertension are mentioned here.

Essential Hypertension

The table given below lists the most important risk factors for essential hypertension. The presence of these risk factors does not guarantees raised blood pressure, but only increases the likelihood of having high blood pressure. The more the risk factors presents, the higher the chance of having high blood pressure or developing it in the future.

Table 1: Risk Factors for Essential Hypertension

Old Age and Gender

Increasing Age Predisposes to High Blood Pressure.

Men are more likely to develop hypertension than women.

Family History

2/3rd of people with essential hypertension have family history of hypertension.

So high blood pressure in family members increases the risk of developing hypertension.


African-American people more likely to develop high blood pressure compared to Caucasians.

Also there hypertension is likely to be more severe.


Cigarette smoking is a well known risk factor for developing hypertension.

It is also a risk factor for many other cardiovascular diseases.


Drinking excessive amount of alcohol can cause high blood pressure.

Lack of Physical Activity

Sedentary lifestyle with very little physical activity increases the risk of developing hypertension.


Excessive body weight (BMI > 25 kg/m2) increases the risk of having high blood pressure.

Unhealthy Diet

Diet low in fruits, vegetables, fibers and high in saturated and total fats and salt can cause high blood pressure (e.g. fast foods etc.)

Increased Salt Intake

High dietary intake of common salt (NaCl) is a risk factor for high blood pressure.


Stress, Coffee, Diabetes

Unknown Factors

Many yet unknown factors may also contribute to high blood pressure.

Secondary Hypertension

The table given below lists some of the most common causes of secondary hypertension. Generally, secondary hypertension is due to kidney dysfunction or hormonal disturbances or a side effect of medications. Differentiating essential hypertension from secondary hypertension is very important because secondary hypertension can be cured if the primary condition causing the raised blood pressure is curable.

Table 2: Common Causes of Secondary Hypertension

Kidney Dysfunction

(Renal Causes)

Renal Artery Stenosis, Polycystic Kidney Disease, Glomerulonephritis, Chronic Pyelonephritis, Renal Tumors, etc.

Hormonal Disturbances (Endocrine Causes)

Pheochromocytoma, Acromegaly, Hyperparathyroidism, Hypothyroidism, Hyperthyroidism, Cushing’s Syndrome, Conn’s Syndrome, etc.

Drugs (Medications)

Oral Contraceptive Pills, Anabolic Steroids, Corticosteroids, Decongestants, Appetite suppressants, NSAIDs etc.

Illegal Drugs like Cocaine, Amphetamine


Coarctation of Aorta, Obstructive Sleep Apnea, Genetic Diseases

The description of the disease conditions mentioned in the table are:

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