In about 10% of people, high blood pressure is caused by another disease (this is called secondary hypertension). In such cases, when the root cause is treated, blood pressure usually returns to normal or is significantly lowered. These causes include the following conditions:
Chronic kidney disease
Tumors or other diseases of the adrenal gland
Coarctation of the aorta -- A narrowing of the aorta that you are born with that can cause high blood pressure in the arms
In the other 90% of cases, the cause of high blood pressure is not known (primary hypertension). Although the specific cause is unknown, certain factors are recognized as contributing to high blood pressure.
Malignant hypertension is extremely high blood pressure that develops suddenly and rapidly and causes some type of organ damage. "Normal" blood pressure is below 120/80. A person with malignant hypertension has a blood pressure that's typically above 180/120. It's considered a hypertensive emergency and should be treated as a medical emergency.
Age: The older you get, the greater the likelihood that you will develop high blood pressure, especially systolic, as your arteries get stiffer. This is largely due to arteriosclerosis, or "hardening of the arteries."
Race: African Americans have high blood pressure more often than whites. They develop high blood pressure at a younger age and develop more severe complications sooner.
Family history (heredity): The tendency to have high blood pressure appears to run in families.
Sex: Generally men have a greater likelihood of developing high blood pressure than women. This likelihood varies according to age and among various ethnic groups.
Factors That Can Be Changed
Obesity: Obesity is defined as being 30% or more over your healthy body weight. It is very closely related to high blood pressure. Indeed, obese people are two to six times more likely to develop high blood pressure than people whose weight is within a healthy range. Medical professionals strongly recommend that all obese people with high blood pressure lose weight until they are within 15% of their healthy body weight. Your health care provider can help you calculate your healthy body weight range.
Sodium (salt) sensitivity: Some people have high sensitivity to sodium (salt), and their blood pressure goes up if they use salt. Reducing sodium intake tends to lower their blood pressure. Americans consume 10-15 times more sodium than they need. Fast foods and processed foods contain particularly high amounts of sodium. Many over-the-counter medicines, such as painkillers, also contain large amounts of sodium. Read labels to find out how much sodium is contained in food items. Avoid those with high sodium levels. Your goal should be to consume no more than 1,500 mg of sodium per day.
Alcohol use: Drinking more than 1-2 drinks of alcohol per day tends to raise blood pressure in those who are sensitive to alcohol.
Birth control pills (oral contraceptive use): Some women who take birth control pills develop high blood pressure.
Lack of exercise (physical inactivity): A sedentary lifestyle contributes to the development of obesity and high blood pressure.
Drugs: Certain drugs, such as amphetamines (stimulants), diet pills, and some pills used for cold and allergy symptoms, tend to raise blood pressure.