What is blood pressure? The regular pumping of the heart causes the blood to flow. When the heart muscle contracts (pumps), the pressure in the arteries and vascular system increases; when the heart muscle relaxes, the pressure decreases. Under normal circumstances, the pressure rises and falls with each heartbeat. For this reason blood pressure has two readings: systolic (the higher reading) and diastolic (the lower reading), and is recorded, for example, as 120/80 in millimeters of mercury.

The muscle layers of the walls of the blood vessels, especially the arterioles (smaller arteries), also are important in determining the blood pressure. Depending on their state of contraction (or tone), they determine the resistance against which the heart has to pump. The higher the pressure, the harder the heart muscle has to work, and this, over time, can damage the heart muscle.

Hypertension becomes more common with increasing age. It is more common in younger men, although between ages 55 and 75 years no significant gender difference exists. Hypertension is currently one of the greatest health problems and causes death from strokes, heart failure, and kidney failure if untreated. It is estimated that only 30 percent of individuals who have the disease are aware of the fact. In people who are treated, there is a consequent decrease in deaths because of stroke, coronary heart disease, and heart failure. Of those who are on treatment, sadly, only 30 percent have their blood pressure controlled to ideal levels. Treatment needs to be monitored and adjusted appropriately.

In 95 percent of patients no specific cause of high blood pressure is found. This is known as primary or essential hypertension. Familial patterns are common, and this suggests there is a genetic link to high blood pressure. Other factors associated with hypertension include cigarette smoking, obesity, alcohol consumption, excessive salt intake, and lack of exercise. In approximately 5 percent of cases a specific, identifiable cause of the high blood pressure may be found, such as kidney disease, hormonal abnormalities, certain medications, and pregnancy (in some instances). These cases are known as secondary hypertension.

Hypertension has many complications. It hastens the process of atherosclerosis (hardening of the arteries) and can even cause rupture of the major artery of the body (aortic aneurysm rupture), with severe bleeding and often death from hemorrhage. Stroke (damage to an area of the brain because of a clot or a bleeding in that area) is a major complication of hypertension, as is an increased tendency to coronary artery disease, heart muscle damage, and heart failure. Untreated hypertension can also cause kidney damage and sight impairment. Most of these problems are related to damage of the blood vessels supplying these organs.

Treatment
The diagnosis of high blood pressure is not a death sentence in itself. Much can be done to improve blood pressure and thereby decrease the numerous and frightening complications. There are two aspects to the treatment; one is the nonmedication aspect, and the other is the use of blood pressure-lowering medications. In many cases both approaches are required; lifestyle changes should be effected in all cases.

The nonmedical treatment includes smoking cessation, decreased alcohol intake, regular exercise, salt restriction, and diet modification. Stress management is also helpful. Exercise is important not only as a treatment, but also as a preventative measure.

Recently a large study, the Dietary Approaches to Stop Hypertension (DASH), showed that a diet that emphasized fruits, vegetables, nuts, and lean meat (fish or poultry) helped to lower blood pressure. This effect was even more marked when salt intake was decreased (the best results were in the lowest sodium-intake group: 1,500 milligrams per day). Although DASH is not based on a vegetarian diet, it recommends four to five servings of vegetables, seven to eight servings of grains, four to five servings of fruit, two to three servings of low-fat or nonfat dairy products, and no more than two small servings of lean meat, fish, or poultry each day. Lifestyle changes were found to be beneficial in conjunction with medication and not in place of medication.

It is interesting to note that lacto-ovovegetarians have lower blood pressure than omnivores. This may be related to lower body mass in vegetarians; higher potassium intake may also play a role. The effects of the increased dietary fiber and polyunsaturated fats in the vegetarian are aspects that are further being investigated as additional positive benefits. The Adventist Health Study confirms that the Adventist lifestyle results in less hypertension in those who follow it.

Weight control is essential. Exercise is pivotal to blood pressure control and the prevention of hypertension as well. A diet rich in fruits, nuts, vegetables, low-fat dairy products, and reduced saturated fats and total fat (DASH) is strongly recommended as the best diet for preventing hypertension. Hypertension begins early in life; therefore, prevention approaches in children are essential. These measures include nutrition education, promotion of physical activity, and a heart-healthy lifestyle.

A number of classes of medications have proved to be very beneficial in the treatment of hypertension. These include diuretics (water-removing tablets), ace inhibitors, beta receptor blockers, angiotensin II receptor blockers, calcium channel blockers, and others--including the older drugs reserpine and alpha methyl dopa. The current recommendations suggest that as well as a diuretic (thiazide), one of the other classes of medication be added. In order to achieve the best blood pressure control, most patients with moderate hypertension often require at least two blood pressure-lowering medications, in addition to lifestyle modification.

The target blood pressure level for patients on treatment for hypertension is a reading lower than 140/90 millimeters of mercury; in patients with diabetes or kidney disease, the goal is lower than 130/80 millimeters of mercury. Adherence to antihypertensive treatment is generally poor, despite the significant benefits related to therapy. Therapy needs to be adjusted to each patient and side effects reduced to a minimum. Because there are so many various medications that are tried and tested, there is scope for finding combinations that suit the specific needs of each patient.

Compliance--that is, regular adherence to lifestyle and medication recommendations--is crucial. The only medication that works is the one that the patient swallows!

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Allan R. Handysides, M.B., Ch.B., F.R.C.P. (c), is director of the General Conference Health Ministries Department; Peter N. Landless, M.B., B.Ch., M.Med., F.C.P.(SA), F.A.C.C., is ICPA executive director and associate director of health ministries.

While this column is provided as a service to our readers, Drs. Landless and Handysides unfortunately cannot enter into personal and private communication with our readers. We recommend that you consult with your personal physician on all matters of your health.