Hypertension isn't called a killer for nothing. High blood pressure is a significant risk factor for developing coronary artery disease (CAD), the leading cause of death in the United States, and it's considered a significant risk for stroke, heart failure, and kidney failure. Anyone with poorly treated hypertension at least doubles his or her risk of developing all of these conditions. And remember, the higher the blood pressure, the higher the danger.
Thus, even individuals who have no symptoms when initially diagnosed with hypertension need to work hard to control blood pressure to prevent these potentially devastating complications. When you're already diagnosed with heart disease and hypertension, then controlling your blood pressure within recommended levels is perhaps the most important step you can take toward preventing or slowing the progress of your heart disease.
Determining the causes of hypertension
In the vast majority (more than 90 percent) of people with high blood pressure, physicians aren't able to determine its exact cause. In medical terms, this condition is known as idiopathic hypertension. That's not to say that physicians are idiots, but that they haven't yet figured out the precise mechanisms, functions, or agents that cause hypertension. Hypertension of an undetermined cause also is termed essential high blood pressure. In the same way that idiopathic doesn't mean that doctors are idiots, neither does essential mean that having hypertension is essential. Quite the contrary! Treating it is what is essential! Look at some of the factors that appear to contribute to hypertension.
- Salt intake: Among the theories about what causes essential high blood pressure, most relate to problems that your kidneys appear to have with handling excess salt. Population studies show that societies in which people consume large amounts of salt (such as the United States) have a correspondingly high incidence of high blood pressure. Similarly, in cultures where salt intake is low, the incidence of high blood pressure is extremely low. Other studies show that for most people with hypertension, restricting salt intake helps lower high blood pressure.
- Inherited predisposition: Hypertension also appears to have a genetic component. Some people may be genetically predisposed to have high blood pressure. However, although hypertension runs in some families, these tendencies may actually result as much from shared lifestyles as they do from shared genetic backgrounds. Doctors certainly know that lifestyle factors, such as obesity (and abdominal obesity, in particular), inactivity, cigarette smoking, and high alcohol consumption all are associated with increased risk of hypertension.
- Known conditions that cause it: In approximately 10 percent of the people with hypertension, the specific underlying cause can be discovered. This condition is known as secondary hypertension, meaning it's a secondary result of a separate primary condition. If the underlying condition can be treated and corrected, then secondary hypertension usually is corrected, too. Conditions known to cause secondary high blood pressure include
• Narrowing of the arteries that supply the kidneys
• Other diseases of kidneys
• Abnormalities in the endocrine system, such as overactive adrenal glands
• Transient conditions such as pregnancy for certain women
• Certain medications that can increase the risk of high blood pressure, such as oral contraceptives or estrogen replacement therapy following menopause
If you're diagnosed with high blood pressure, your doctor will explore any of these potential underlying causes for hypertension prior to making the diagnosis.
Checking out other risk factors
Although medical science may not know the exact mechanisms that cause essential hypertension, a number of conditions are strongly associated with increases in high blood pressure. Arresting any one of this gang of probable causes usually leads to lower blood pressure. For many people, controlling these conditions actually returns their blood pressure to normal levels.
- Obesity: Hypertension is most clearly associated with obesity (weighing more than 20 percent above your desirable body weight). Obesity contributes to an estimated 40 percent or more of all high blood pressure cases in the United States. Although not everyone who is overweight has high blood pressure, the association remains crystal clear.
- Cigarette smoking: Cigarette smoking and the use of other tobacco products increase blood pressure, both in the short term while you're smoking or chewing and in the long term, because components in the smoke or chewing tobacco, such as nicotine, cause your arteries to constrict. Childhood experiments with the nozzle on a garden hose indicate what happens when you force the same volume of liquid through a smaller opening. That higher pressure isn't a happy thing for your arteries.
- Alcohol intake: Drinking small to moderate amounts of alcohol (fewer than two beers, two glasses of wine, or one shot of distilled spirits) per day has been shown in a number of studies to reduce mortality from CAD. Higher consumption of alcohol (three or more alcoholic drinks per day), however, clearly is associated with increased blood pressure, not to mention an increased risk of dying from heart disease.
- Physical inactivity: People who are physically inactive increase their likelihood of developing high blood pressure. In one large study of more than 16,000 individuals, inactive people were 35 percent more likely to develop hypertension than were active people, regardless of whether they had a family history of high blood pressure or a personal history of being overweight.
