FRIDAY, May 14, 2004 (HealthDayNews) -- Doctors call it "prehypertension," and it's a new reason why more Americans 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," said 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 last year.
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 what sufferers can do about the problems.
About 45 million Americans who previously thought they had normal blood pressure are considered to have prehypertension. That's on top of 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 American men and women.
High blood pressure can even occur in children, but it's more common among people over age 35, according to the American Heart Association (AHA). It's particularly prevalent among blacks, 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.
Blood pressure problems can strike even superbly conditioned athletes like Linda Johns. The 43-year-old has finished nine Ironman Triathalons and more than 20 marathons. She also exercises six or seven days a week, bicycles 160 to 200 miles a week, runs 28 to 35 miles and swims 7,000 to 8,000 yards.
Her blood pressure had been steadily inching up over the years, her doctor ticking off the rise with each annual examination. Then last year, he decided her blood pressure had climbed high enough. He put her on Diovan, which works by blocking a hormone that causes your arteries to constrict.
"Who would have thought that me, being the epitome of good health, would have high blood pressure?" said Johns, who works in marketing and sales promotion for a Portland, Ore., television station. "Everyone should get their blood pressure checked on a regular basis. There are no boundaries on who might have it."
It's impossible to know without testing if you're suffering from high blood pressure because the condition has no symptoms. One in four adult Americans has high blood pressure, and nearly a third of them don't know it, the AHA says.
Prehypertension was created as a condition last year because doctors 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," said 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."
Jones said 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 said. "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."
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. Doctors are now encouraged to emphasize the use of diuretics, which help rid the body of excess fluids and salt, to treat hypertension, Jones said.
"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," Jones said.
The guidelines also recommend using a combination of medicines to treat high blood pressure, especially when the condition is first diagnosed, Schiffrin said.
"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," Schiffrin added.
Most clinical trials have found that between two to four medicines working in concert have helped people lower their blood pressure, he said.
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 says.
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.
The case of Johns, the marathoner, emphasizes the mystery surrounding the causes of high blood pressure. According to the AHA, many people think hypertension is a "stress disease" resulting from overwork, no exercise, drinking, smoking or a poor diet.
"The truth is, except in a few rare cases, doctors don't know what causes high blood pressure," the AHA Web site says. "They do know that about 50 million Americans have it, and nearly half are women. Only a small portion of people with the disease are adequately treated."
Johns figures her high blood pressure is inherited. "My mom has high blood pressure, and my dad suffered from high blood pressure before his death," she said.
Because she's so fit, her doctor skipped the lifestyle adjustments that most physicians would recommend before putting a high blood pressure sufferer on medication. Those adjustments include a healthier diet, more exercise and a decrease in sodium and alcohol intake.
So Johns takes her medicine once a day, and that's been enough to bring her blood pressure down toward normal. She's happy that it's under control, and that she found out about her hypertension before it had a chance to do real damage to her body.
"I think that's what's key, is catching it early," Johns said. "Obviously, it can lead to heart attack or stroke, but now I don't have to worry about that."