Blood Pressure

High Blood Pressure affects an estimated 50 million Americans. One in four adults have High Blood Pressure, however about 30% are unaware they have it and another 30% are not well-controlled (B/P 140/90) despite seeking treatment (Arch Int Med, 1997; 157). The cause of hypertension is unknown for 90-95 percent of the cases but it is easily diagnosed and usually controllable.

Blood pressure typically increases with aging (see bar graph below), however, it is no longer viewed as a normal aspect of aging because this pattern of elevation with age is not found in non-industrialized countries. Among those age 60 and older, about 60 percent of Caucasians and 71% of African Americans have hypertension. In the over 75 population, 56% of men and 70% of women have high blood pressure.

Estimated Percentage of Americans Age 20 and Older With High Blood Pressure by Age and Sex United States: 1994

High blood pressure causes the heart to work harder than normal. If high blood pressure isn't treated it can cause several related conditions. For example the increased workload on the heart can cause it to enlarge which may result in congestive heart failure as your heart enlarges from the increased workload or it may lead to renal failure. Over time, High Blood Pressure accelerates atherosclerosis and causes your arteries and arterioles to become scarred, hardened and less elastic. High Blood Pressure is a major risk factor for heart attacks, strokes, and kidney failure. People with hypertension have three times the risk of developing cardiovascular disease as someone with normal blood pressure.

Themeasurement of blood pressure assesses the amount of force being exerted against the walls of blood vessels in millimeters of mercury (mmHg). There are two measurements for blood pressure:

• Systolic pressure is measured when the heart muscle is contracting, and
• Diastolic pressure is measured when the heart muscle is relaxing.

High Blood Pressure is defined as a systolic pressure of >140 mmHg systolic and/or a diastolic pressure of >90 mmHg. Isolated systolic hypertension (ISH) is a disorder of aging and is defined as a systolic blood pressure of =160 mmHg with a diastolic blood pressure of =90 mmHg. Less than one percent of persons age 50 have ISH but the prevalence increases to 12.6% by age 70 and 23.6% by age 80. The table below provides a summary of how blood pressures are interpreted.

Systolic pressure tends to rise with age while diastolic pressure rises until about age 60 when it levels off. Systolic pressure is more strongly correlated with future cardiovascular problems than diastolic pressure. It is caused by increased resistance in the blood vessels. With aging the blood vessels become less elastic and lose some of their ability to dilate. Atherosclerosis can cause clog vessels with plaque which further contributes to the stiffening and narrowing of arterial walls.

Who is at risk for hypertension? Click on the link "Risk Factors for High Blood Pressure" to find out.

Treatment of Hypertension

Treatment of hypertension usually begins with lifestyle modifications. The Joint National Committee on Detection, Evaluation and Treatment of High Blood Pressure recommendations include following:

• Lose excess weight. Losing as few as 10 pounds can bring a meaningful drop in high blood pressure. Weight loss also can also increase the effectiveness of medications.
• Exercise. Regular, moderate activity lasting 30 to 45 minutes most days of the week, may help prevent or lower high blood pressure. People with normal blood pressure are unfit have a 20 percent to 50 percent increased risk of developing hypertension compared with more active people.
• Limit sodium. Some individuals are sensitive to salt and may find it raises their blood pressure. In that case, lowering salt makes sense. However, salt (sodium chloride) intake doesn't always cause high blood pressure and avoiding it will not necessarily prevent hypertension.

If a 6-month trial of lifestyle modifications fails to reduce blood pressure then medications may be necessary. Medications may include:

• Diuretics (e.g., Dyazide, Lasix) are often the first choice in drug treatment. Diuretics act on your kidneys to help your body eliminate sodium and water
• Alpha, Beta, And Alpha-Beta Adrenergic Blockers (e.g., Inderal, Tenormin, Lopressor, Normodyne) work by blocking the effects of certain chemicals in your body. With some of these drugs, your heart may beat more slowly and less forcefully. With others, your blood vessels may dilate and you may feel faint when you stand up.
• ACE Inhibitors and Angiotensin Receptor Blockers. Angiotensin converting enzyme (ACE) inhibitors block the formation of a natural body chemical called angiotensin II and thereby relax your blood vessels. Some people who take ACE inhibitors (e.g., Enalaprilª, Vasotecª, Priniviª) develop a bothersome cough and need to have their medication switched.
• Calcium Channel Blockers (e.g., Verapamil, Calan, Cardiazem, Norvasc , Procardia) reduce blood flow and relax blood vessels. Only the long-acting calcium channel blockers are recommended for high blood pressure.