Hypertension, or high blood pressure, refers to persistently elevated pressure of blood within the arteries, which carry blood from the heart through the body. The exertion of excessive force on the artery walls may cause damage to the arteries themselves and thereby to the heart, kidneys, and brain, leading to heart attack, kidney failure, and stroke.

Causes

Although many people believe that hypertension is caused by extreme activity or tension, this theory has not been proved.

When no underlying cause of hypertension is discovered, the disease is called primary, or essential, hypertension. If another disease, such as kidney or endocrine disease, causes the elevated blood pressure, the condition is called secondary hypertension.

Risk Factors

Contrary to popular belief, there is no typical high strung hypertensive person. However, some people are more susceptible to developing high blood pressure than others. Heredity appears to play a role; individuals whose parents have hypertension are at greater risk of having the disease themselves. In the past, hypertension was attributed to aging, but current evidence indicates that age is not a primary factor. The incidence of hypertension in African Americans, both children and adults, is about twice that in Caucasians.

Overweight, prolonged stress, smoking, drinking, and excessive sodium in the diet (which causes fluid retention) may increase blood pressure, especially in persons prone to hypertension. There are also indications that use of oral contraceptives may contribute to increased blood pressure; however, this is more likely to occur in women who are overweight, who have other hypertensive risk factors (such as smoking), or whose parents have hypertension.

Symptoms

Hypertension has been called the silent disease because it often has no obvious symptoms. A person can have high blood pressure for years without noticing any symptoms. Symptoms include headache, fatigue, dizziness, flushing of the face, ringing in the ears, and frequent nosebleeds. However, these symptoms may also result from other conditions.

Diagnosis

To diagnose hypertension, a simple, risk-free, painless test using a stethoscope and a sphygmomanometer is used. Blood pressure is measured in a main artery of the arm by first shutting off and then releasing the flow of blood in the artery with the inflatable cuff of the sphygmomanometer while listening to the arterial pulse with the stethoscope.

The blood pressure measurements are given as the systolic pressure (the pressure at which the first beat of the pulse can be heard as gradual deflation of the cuff begins) over the diastolic pressure (the pressure at which steady flow through the artery can be heard as the cuff is deflated) -- for example, 150/95. The systolic pressure essentially measures the pressure of the heart during a contraction. The diastolic pressure is that which exists when the heart is filling between beats.

Although diastolic pressure is considerably lower than systolic, there is still pressure in the body when the heart is filling. Both values have diagnostic importance. An unusually high systolic pressure may mean that the heart is pumping too hard or the arteries are stiff; a high diastolic pressure means that the arteries have abnormally high muscular tone or resistance.

Normal blood pressure is about 80/46 at birth and climbs as age increases. The normal adult pressure is about 120/80.

Treatment

Fortunately, hypertension responds well to treatment. When the condition is mild (a blood pressure of about 140/90) and there is no indication of other disease, a doctor may suggest lifestyle changes before prescribing medication. These changes may include weight loss, a regular exercise program, and strict limitation of sodium intake, which affects fluid balance and volume and therefore blood pressure. Controlling sodium in the diet requires restriction of table salt as well as careful scrutiny of all food and drug labels. If medication is indicated, a physician may prescribe one or several drugs. Commonly prescribed drugs include diuretics, angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, and calcium channel blockers.

While tension and stress do not directly cause hypertension, these factors do affect the condition. Persons with hypertension, therefore, are urged to avoid high-pressure situations and to learn to deal with stress. Biofeedback, self-hypnosis, and meditation have proved useful for reducing stress and may help those with hypertension.

Blood pressure can be monitored at home with a special kit. If three separate elevated readings (above 140/90 in adults) are obtained, a trip to the doctor is in order. Furthermore, everyone should have his or her blood pressure measured by a health-care professional at least once a year. Persons with a history of hypertension or with any of the risk factors for hypertension should carefully follow their physician's recommendations for periodic blood pressure checks. It is also recommended that children of parents with hypertension begin to receive regular blood pressure measurements early in life.