High Blood Pressure

An estimated 60 million Americans have hypertension, and at least 50 percent of those with the disease are not aware of it.

Seventy percent of those affected have only mild hypertension. High blood pressure runs in families. Children with one hypertensive parent have a higher risk than those with no high blood pressure in the family.

Blood pressure is the force exerted by the bloodstream against the walls of the arteries; hypertension is the term used for abnormally high blood pressure.

The heart pumps blood through the arteries to the organs and muscles, and the blood returns to their heart via the veins. The veins and arteries are joined by small arteries called arterioles, which control the blood pressure. When they open, blood pressure goes down, and when they close, blood pressure goes up.

Blood pressure varies with age, emotional state, activity level, and time of day. It is expressed as two figures, the normal range being 110/80 to 140/90. The first, higher figure in each pair is the systolic pressure, which is the peak pressure reached when the heart contracts and forces blood into the arteries. The low figure is the diastolic pressure, the lower pressure when the heart rests between beats.

Diastolic pressure is usually used to measure the severity of high blood pressure, as this is the pressure the arteries are under even when at rest. A high normal reading is 85 to 89; mild hypertension is 90 to 104; moderately severe hypertension is 115 and higher. Two high readings on consecutive visits to the doctor are required before a diagnosis of hypertension is made, because even the stress and worry of the visit can be enough to cause blood pressure to rise above normal.

One in ten hypertensive have the condition as a result of diabetes, kidney disease, tumors in the adrenal glands, pregnancy, birth control pills, or congenital narrowing of the aorta, the largest artery in the body. The other 90 percent of people with hypertension can be successfully treated (but not cured) with medication, accompanied by a low salt diet and life style changes.

Blood pressure elevations are a serious health hazard, as they are a leading cause of the half million strokes suffered each year that are responsible for as many as 170,000 deaths. In addition, high blood pressure left untreated for 10 to 1 years can cause serious damage to the arteries in the brain, eyes, kidneys, and heart. People with high blood pressure are twice as likely to die from heart disease as those with normal blood pressure.

If the high blood pressure is caught early and treated, then a person has a normal life expectancy. In fact, early detection and treatment of hypertension has made a significant contribution to the 45 percent reduction in death from strokes over the last 13 years and the 31 percent reduction in cases of heart disease during the same period.

The vast majority of people with high blood pressure do not experience any symptoms, which is the major problem for diagnosis. When the problem becomes a matter of very serious concern, however, the patient may experience headaches, changes in vision, and difficulty in breathing.