High Blood Pressure Puts Many US Adults At Risk 

May Is National High Blood Pressure Education Month

Health experts call it "prehypertension," and it points to a reason why more US adults than ever before should be concerned about high blood pressure.

People with prehypertension have blood pressure ranging from 120/80 to 139/89, readings previously considered to be the high end of normal.

"We expanded the limits based on long-standing evidence that blood pressures above 115 or 120 carry a higher risk of cardiovascular disease," says Dr. Dan Jones, dean of the University of Mississippi School of Medicine and a member of the government-sponsored board that redrafted the guidelines for hypertension in 2003.

Learning More about High Blood Pressure

And with May designated National High Blood Pressure Education Month, health experts hope to focus attention on prehypertension and high blood pressure, and offer information on prevention and management.

About 45 million Americans who previously thought they had normal blood pressure are considered to have prehypertension. That is in addition to the 60 million people who have full-blown high blood pressure.

High blood pressure increases the risk of coronary heart disease. Left untreated, it can cause heart attack and stroke - the first and third leading causes of death, respectively, among US men and women.

High blood pressure can even occur in children, but it is more common among people over age 35, according to the American Heart Association (AHA).

It is particularly prevalent among African Americans; middle-aged and elderly people; the obese; heavy drinkers; and women taking birth control pills. People with diabetes, gout, or kidney disease also are more likely to develop high blood pressure.

It is impossible to know without testing if a person has high blood pressure because the condition has no symptoms. One in four adult Americans has high blood pressure, and nearly a third of them do not know it, the AHA says.

Prehypertension was identified as a risk in guidelines because physicians found people's bodies were suffering damage from their elevated blood pressure, although not as much as if they had true hypertension.

"There were certain patients at high risk," says Dr. Ernesto Schiffrin, a professor of medicine at the University of Montreal. "Diabetics and people with chronic renal failure had to be treated at lower blood pressure levels than earlier recommended."

Dr. Jones says people with elevated, but not high, blood pressure had been told in the past that they were suffering from "high-normal" blood pressure, a diagnosis that did not indicate the seriousness of the situation.

"That term was not getting the attention of the public or of clinicians," he says. "We are more keenly aware that it's not healthy to have blood pressure in that range. This was simply a change in nomenclature to make people more aware of the risks we already knew about."

Focus on Prevention Takes Center Stage

The revised guidelines recommend that people suffering from prehypertension make lifestyle changes to treat the condition. These include controlling their weight, taking part in regular physical exercise, and moderating their intake of salt and alcohol.

People with prehypertension also are encouraged to take part in the so-called DASH (Dietary Approaches to Stop Hypertension) diet, which emphasizes fruits, vegetables, and low-fat dairy products. It has been proven to lower blood pressure.

Another element of the new guidelines involves medications for people with full-fledged high blood pressure. Physicians are now encouraged to emphasize the use of diuretics, which help rid the body of excess fluids and salt, to treat hypertension, Dr. Jones says.

"The recommendation was for clinicians to choose between a group of medications, but that preference should be given to diuretics for people who don't have a special reason to take another type of medication," Dr. Jones says.

Diuretics are proven to work well against high blood pressure, but in the past there was concern that side effects such as low potassium and elevated blood sugar made them less safe for some patients.

"While those side effects are there in some patients, recent evidence clearly indicates that diuretics are equal or superior to other types of blood pressure medication," Dr. Jones says. "Diuretics also are inexpensive, and part of this is cost-effectiveness."

The guidelines also recommend using a combination of medications to treat high blood pressure, especially when the condition is first diagnosed, Dr. Schiffrin says.

"The diuretics should be given priority," Dr. Schiffrin says. "It was considered that all hypertensives should have a diuretic as part of their medicinal cocktail. But it was found that many patients require more than one agent."

Most clinical trials have found that between two to four medicines working in concert have helped people lower their blood pressure, he says.

Some well-established therapies include beta blockers, which reduce the heart rate and its output of blood. Other beneficial drugs are ACE (angiotensin converting enzyme) inhibitors, angiotensin II receptor blockers and calcium channel blockers, the AHA states.

ACE inhibitors interfere with the body's production of angiotensin, a chemical that causes arteries to constrict. Angiotensin II receptor blockers thwart the effects of angiotensin. And calcium channel blockers can cut the heart rate and relax blood vessels.

Always consult your physician for more information.

Online Resources

American Heart Association

Centers for Disease Control and Prevention (CDC) 

Guide to Lowering Blood Pressure (NHLBI)

HealthierUS.Gov

National Heart, Lung, and Blood Institute (NHLBI) 

National Institutes of Health (NIH)

National Library of Medicine

The Heart Truth National Awareness Campaign

May 2004

High Blood Pressure Puts Many US Adults At Risk

Blood Pressure FAQ

Blood pressure, measured with a blood pressure cuff and stethoscope by a nurse or other healthcare provider, is the force of the blood pushing against the artery walls.

Each time the heart beats, it pumps blood into the arteries, resulting in the highest blood pressure as the heart contracts.

One cannot take his/her own blood pressure unless an electronic blood pressure monitoring device is used. Electronic blood pressure monitors may also measure the heart rate, or pulse.

Two numbers are recorded when measuring blood pressure. The higher number, or systolic pressure, refers to the pressure inside the artery when the heart contracts and pumps blood through the body.

The lower number, or diastolic pressure, refers to the pressure inside the artery when the heart is at rest and is filling with blood.

Both the systolic and diastolic pressures are recorded as "mm Hg" (millimeters of mercury). This recording represents how high the mercury column is raised by the pressure of the blood.

High blood pressure, or hypertension, directly increases the risk of coronary heart disease (heart attack) and stroke (brain attack). With high blood pressure, the arteries may have an increased resistance against the flow of blood, causing the heart to pump harder to circulate the blood.

According to the National Heart, Lung, and Blood Institute (NHLBI), high blood pressure for adults is defined as:

140 mm Hg or greater systolic pressure

and

90 mm Hg or greater diastolic pressure

In an update of NHLBI guidelines for hypertension in 2003, a new blood pressure category was added called prehypertension:

120 mm Hg – 139 mm Hg systolic pressure

and

80 mm Hg – 89 mm Hg diastolic pressure

The new NHLBI guidelines now define normal blood pressure as follows:

Less than 120 mm Hg systolic pressure

and

Less than 80 mm Hg diastolic pressure

These numbers should be used as a guide only. A single elevated blood pressure measurement is not necessarily an indication of a problem.

A physician will want to see multiple blood pressure measurements over several days or weeks before making a diagnosis of hypertension (high blood pressure) and initiating treatment.

A person who normally runs a lower-than-usual blood pressure may be considered hypertensive with lower blood pressure measurements than 140/90.

Always consult your physician for more information.

Risk Factors for High Blood Pressure

High blood pressure can occur in anyone, but is particularly prevalent in:

• persons with diabetes mellitus, gout, or kidney disease
  
• African-Americans (particularly those who live in the southeastern United States)
  
• persons in their early to middle adult years; men in this age group have higher blood pressure more often than women in this age group
  
• persons in their middle to later adult years; women in this age group have higher blood pressure more often than men in this age group (more women have high blood pressure after menopause than men of the same age)
  
• middle-aged and elderly people - more than half of all Americans age 65 and older have high blood pressure
  
• persons whose parents or grandparents have/had high blood pressure.
  obese people
  
• heavy drinkers of alcohol.
  women who are taking oral contraceptives
  

Always consult your physician for more information.