Hypertension - Causes

High blood pressure can be caused by certain events in a person's life. For example, strenuous physical activity or stress can cause blood pressure to rise. However, high blood pressure is usually temporary in such cases. When the activity ceases or the stress goes away, the blood pressure returns to normal. This form of high blood pressure is not regarded as a form of hypertension.

True hypertension exists only when a person has high blood pressure readings on a number of different occasions. If a doctor suspects hypertension, he or she will take a number of blood pressure readings over a period of weeks. If those readings are consistently high, the patient may have hypertension.

The cause of hypertension in 90 to 95 percent of all cases is not known. One important factor may be heredity. People who have family members with hypertension are more likely to develop the condition than people whose family members have no hypertension. Hypertension with no known cause is called primary hypertension.

Hypertension can also be caused by a variety of medical conditions. For example, people with kidney disorders may develop hypertension. The kidneys regulate the balance of water and salt in the body. If the kidneys do not function normally, the amount of salt and water in the body may increase. This increase can cause high blood pressure.

Other conditions that can cause hypertension include blood vessel diseases, disorders of the thyroid or other glands, alcoholism (see alcoholism entry), pregnancy, and the use of certain prescription drugs. Hypertension caused by some other medical problem is known as secondary hypertension.

Certain factors are known to increase a person's risk for hypertension. These factors include:

• Age over sixty
• Male sex
• Heredity
• Sensitivity to table salt
• Obesity (see obesity entry)
• Inactive lifestyle
• Heavy alcohol consumption
• Use of oral contraceptives (birth control pills)