High Blood Pressure

High blood pressure was once just a concern for people entering their middle-aged years. Now, with an epidemic of obesity and increasing cases of diabetes, it's a problem for young people too.

A recent federal study determined that having even slightly elevated blood pressure when you are young can lead to serious heart problems in middle age.

Persistently elevated blood pressure, or hypertension, is one that tops 140/90, a reading that measures the force of pressure in the heart as it contracts and as it relaxes between contractions. Hypertension has been long implicated as a risk factor in a range of cardiovascular diseases.

But the recent study suggests that pressure just below that threshold -- or high normal pressure -- begins to fuel heart damage in people as young as 20 and can lead to changes in heart muscle function in as little as 25 years.

One in 25 teens

According to the Nemours Foundation, a non-profit children's health organization, about one in 25 teenagers has elevated blood pressure. The foundation says there can be many reasons, but most have to do with an unhealthy lifestyle – a bad diet, excess weight, stress, and too little physical activity.

One risk factor for high blood pressure in teens may be spending hours each day on the Internet.

Researchers at Henry Ford Hospital in Detroit discovered teens who spend at least 14 hours a week on the Internet had an increased risk of elevated blood pressure. When they examined 134 teens who fit the category of heavy Internet users, 26 of them had higher than normal blood pressure.

These findings add to other research that seems to suggest an association between heavy Internet use and a number of health risks like addiction, anxiety, depression, obesity, and social isolation.

Dial it back

Andrea Cassidy-Bushrow, the study’s lead author, says the take-home message for teens and parents is moderation.

“Using the Internet is part of our daily life but it shouldn’t consume us,” she said. “In our study, teens considered heavy Internet users were on the Internet an average of 25 hours a week.”

Cassidy-Bushrow urges young people to take regular breaks from their computer or smartphone and engage in some form of physical activity. She also recommends parents place limits on their children’s’ time at home on the Internet.

“I think two hours a day, five days a week is good rule of thumb,” she said.

The study estimates teens spend an average of 15 hours a week online, either at school or at home. Forty-three percent of heavy Internet users were considered overweight compared to 26% of light Internet users.

It's a grown-up affliction but an alarming number of children are beginning to feel its effects: hypertension, or high blood pressure.

The typical person suffering from high blood pressure is middle aged, stressed out and overweight. However, the average age of people with hypertension is steadily declining.

More than 50 million Americans are now believed to suffer from hypertension, putting them at increased risk for cardiovascular disease, end-stage renal disease, and cerebrovascular accidents.

And now doctors estimate that nearly 5% of the pediatric population has unhealthy levels of blood pressure.

Lifestyle factors

Hypertension can have many causes but it is primarily influenced by lifestyle factors. Being overweight, not eating properly and getting little or no exercise can all be contributors.

That may be why so many children are now affected. The rise in childhood hypertension coincides with the rise in childhood obesity.

“Hypertension puts a strain on the cardiovascular system, and makes children at risk for heart disease and chronic kidney disease later in life,” said Dr. Robert Woroniecki,of Stony Brook Children’s Hospital. “Conversely, sometimes chronic kidney disease leads to high blood pressure. Whatever the cause, the effects can dramatically influence a child’s health.”

High blood pressure poses a different sort of problem for children's health, but it poses a problem nonetheless. In adults, high blood pressure can mean the patient is at short-term risk of a heart attack or stroke.

Future problems

Not so with children but hypertension can still cause changes in your child’s body, putting them at risk for future complications. Once they reach middle age, these children may have even more severe health problems than do adults diagnosed during middle age.

High blood pressure has no symptoms, leading it to be sometimes called “the silent killer.” But being overweight or obese are big risk factors.

Woroniecki says children who meet this physical description should get regular blood pressure readings. Until recently pediatricians were not all that likely to screen their young patients for high blood pressure because it was so rare.

Difficult to diagnose

Diagnosing high blood pressure in children is more difficult than in adults. According to the Mayo Clinic, pediatric hypertension is defined as “blood pressure that's the same as or higher than 95% of children who are the same sex, age and height as your child.”

There isn't a simple target blood pressure reading the problem in all ages for children, because what's considered normal blood pressure changes as children grow.

But the condition in children can occur for the same reasons it shows up in adults -- being overweight, eating a poor diet and not exercising.

Other causes

While hypertension can be addressed in these children by having them make lifestyle changes, some cases are more complicated and may require medication. For example, the Mayo Clinic notes that high blood pressure in children under 10 is usually caused by an underlying medical condition.

For adolescents, the American Heart Association says age, body size and the degree of sexual maturation are major factors in determining blood pressure levels. Heavier and more sexually mature teenagers tend to have higher blood pressure.

The group cites research suggesting teens who are obese and have high blood pressure may develop thicker arteries by age 30. Fatty buildups in artery walls can lead to a variety of health problems including heart disease and stroke.  

Besides high unemployment, the U.S. is experiencing high rates of under-employment, with more people working part-time and earning less than they need to sustain themselves and their families.

Besides the economic ramifications, researchers at the University of California (UC) Davis say there appear to be health consequences as well. They found that employees earning the lowest wages have a higher risk of hypertension than workers with the highest wages, even if the high-wage jobs carry a lot of stress. The correlation between wages and hypertension was especially strong among women and workers under 45.

“We were surprised that low wages were such a strong risk factor for two populations not typically associated with hypertension, which is more often linked with being older and male,” said J. Paul Leigh, senior author of the study and professor of public health sciences at UC Davis. “Our outcome shows that women and younger employees working at the lowest pay scales should be screened regularly for hypertension as well.”

New focus of research

The study, published in the December issue of the European Journal of Public Health, is believed to be the first to isolate the role of wages in hypertension, which occurs when the force of circulating blood against artery walls is too high. According to the Centers for Disease Control and Prevention (CDC), hypertension affects approximately 1 in 3 adults in the U.S. and costs more than $90 billion each year in health-care services, medications and missed work days. It also is a major contributor to heart disease and stroke, both of which are leading causes of death and disability.

What's surprising is that hypertension has previously been assumed to afflict the stressed-out corporate executive, faced with the responsibilities of meeting profit projections or bearing other stressful burdens. But the UC study suggests it is the people working for them who are feeling the effects of the stress.

While there is a known association between lower socioeconomic status and hypertension, determining the specific reason for that association has been difficult, according to Leigh. Other researchers have focused on factors such as occupation, job strain, education and insurance coverage, with mixed results. Leigh’s study was the first to focus on wages and hypertension.

The role of wages

“By isolating a direct and fundamental aspect of work that people greatly value, we were able to shed light on the relationship between socioeconomic status and circulatory health,” said Leigh. “Wages are also a part of the employment environment that easily can be changed. Policymakers can raise the minimum wage, which tends to increase wages overall and could have significant public-health benefits.”

Leigh is not the first researcher to express concern that young people, especially, are not being adequately screened for high blood pressure. In November research presented at the American Heart Association's Scientific Sessions 2012 found that adults 18-24 years old with high blood pressure were 28 percent less likely to be diagnosed during doctor visits than those 60 and older.

"These young patients come to the clinic and their blood pressure is recorded," said Heather Johnson, M.D., lead researcher of the study. "They have high blood pressure, but there's no documentation of a diagnosis."

High blood pressure is a major risk factor for heart attack and stroke. While more prevalent in older Americans, about 29 percent of all U.S. adults have hypertension, according to American Heart Association statistics. About 11 percent of men and 7 percent of women 20-34 years old have high blood pressure.

Consumers spend billions of dollars on medication to control high blood pressure but getting plenty of vitamin D might help too. Research continues to suggest that the vitamin, present in dairy foods and sunlight, has benefits for the circulatory system.

In March researchers at Boston's Brigham and Women's Hospital conducted a study that suggested moderate amounts of vitamin D supplements could reduce high blood pressure. Since African Americans tend to have high higher incidence of hypertension, the study followed 250 African American adults.

"We found that vitamin D supplementation modestly but effectively lowered blood pressure," said Dr. John Forman, who led the research team. "And people who were taking a placebo had a slight increase in their blood pressure."

Vitamin D has long been thought to have some benefits when it comes to blood pressure. Some previous students on animals achieved that result, though the findings have not been universally accepted.

No proof

“In population studies, people with low levels of vitamin D seem to have a high risk of developing high blood pressure than those with higher levels of vitamin D,” according to researchers at the University of Maryland Medical Center. “However, there's no proof that low levels of vitamin D cause high blood pressure in healthy people.”

Dr. Sheldon G. Sheps, of the Mayo Clinic, agrees that the role too little vitamin D plays in developing high blood pressure is not exactly clear. But he says a vitamin D deficiency may be linked to heart disease and a higher risk of high blood pressure. It's too early to know, he says. More research is needed.

However, there appears to be a growing consensus that it could be beneficial. Researchers at Edinburgh University in the UK are so convinced that vitamin D is effective in reducing high blood pressure, as well as heart attack and stroke risk, that they suggest getting vitamin D from sunlight has benefits that may far outweigh skin cancer risks. Their research focuses on ultra violet (UV) rays, which reportedly release a compound in the body that lowers blood pressure.

Growing threat

High blood pressure is a growing threat, especially to the aging population. While being overweight, getting little exercise and consuming excessive levels of sodium are all contributors, not all of its causes are understood.

High blood pressure occurs when the heart has to work harder to move blood through veins and arteries, usually because of rigidity in the blood vessels. Prolonged high blood pressure can cause the heart to enlarge. The high pressure of the blood flowing through the veins can eventually cause a blood vessel to break, causing a stroke.

If increasing vitamin D intake can be shown to prevent high blood pressure, it could provide an easy and effective treatment. It might also save money on prescription medications.

What to do

There are many sources of vitamin D that could probe healthy in other ways, even if it doesn't reduce high blood pressure. Spending time outdoors, with exposure to the sun, is one way but should be measured against the risk of skin cancer.

Some foods also are rich sources of vitamin D. Dairy products, like milk, cheese and yogurt are good sources. You can also get vitamin D from salmon, tuna, flounder, cereal, pork, eggs, mushrooms and liver.

Vitamin D is also available in supplements. Popular brands cost about $25 for 120 capsules, a four month supply. As with any health or diet issue, discuss the role of vitamin D in your diet, and as a tool to control blood pressure, with your physician.

It sounds so simple, yet fewer than one in three people manage to do it.

According to new research in the American Heart Association journal Circulation, you might be able to cut your risk for heart disease by half or more by simultaneously controlling your high blood pressure and high cholesterol.

Researchers also found that prescribing medications to better manage blood pressure and cholesterol would greatly benefit people who are older, diabetic, have cardiovascular disease or are Hispanic or black. And they say going to the doctor at least twice a year could help.

Millions affected

Undertreated high blood pressure and cholesterol affect millions, posing a major public health threat, said Brent M. Egan, M.D., lead study author and a professor of medicine and pharmacology at Medical University of South Carolina in Charleston, S.C.

"The reality is, we know more than enough to prevent 75% of heart disease and strokes, but we're not doing everything we could be doing or even doing it at a reasonable level," he said. "We've made some gradual improvements over the years, but there is still a lot of progress to be made."

High blood pressure affects about 33% of the U.S. adult population and doubles the risk for heart disease. About 32 million people have dangerously high total blood cholesterol levels of 240 mg/dL or higher. Previous research indicates that treating high blood pressure reduces the risk of heart disease by 25% and treating high cholesterol in hypertensive patients can lower the risk by more than 35%, researchers said.

Monitoring cholesterol

Cholesterol readings need closer attention, Egan said. "If patients' cholesterol tests show a good high-density lipoprotein (HDL) level, which is the healthy, protective cholesterol, then the low-density lipoprotein (LDL) number might get overlooked. Unfortunately, not all HDL is equally protective and some people with a normal HDL are at high risk. In those patients, there might be a false sense of assurance that cholesterol really isn't a problem.

“But LDL and non-HDL readings are the ones to really watch,” he notes. “Patients seeing their doctors for blood pressure treatment should ask about their LDL and non-HDL levels and make sure both are under control at the same time."

The findings are based on data of more than 17,000 adults who participated in the National Health and Nutrition Examination Surveys during in 1988-94, 1999-2004 and 2005-10.

In addition to reviewing patients' blood pressure and cholesterol levels, researchers considered race, age, insurance status, whether patients smoked, had diabetes, had diagnosed heart disease and/or chronic kidney disease, and if they visited a doctor every year.

You see them everywhere: the supermarket, drug stores, discount superstore. It's those blood pressure monitoring kiosks where you stick your arm in the cuff and get a reading.

But here's something to keep in mind: The next time you do that, you could get an inaccurate reading unless the cuff is your size.

Correct cuff size is a critical factor in measuring blood pressure. Using a too-small cuff will result in an artificially high blood pressure reading; a too-large cuff may not work at all or result in an inaccurately low blood pressure reading.

The Food and Drug Administration (FDA) wants you to know that blood pressure cuffs on public kiosks don’t fit everyone -- and might not be accurate for every user.

“They are easily accessible and easy to use,” says Luke Herbertson, PhD, a biomedical engineer at FDA. “But it’s misleading to think that the devices are appropriate for everybody. They are not one-size-fits-all.”

Serious business

Blood pressure is an important indicator of cardiovascular health. High blood pressure (hypertension) is called a “silent killer” because it may not show any symptoms. It increases the risk of stroke, heart attack, heart failure, kidney failure and death. The higher the blood pressure, the greater the risk.

Hypertension affects nearly one in three adults in the United States, and in most patients, it is found only when they have their blood pressure checked.

The need for accuracy

In a clinic or a medical office, this is done by using blood pressure cuffs of various sizes to ensure the reading is accurate. For example, a toddler’s blood pressure is checked by using an extra-small children’s cuff, but a football lineman’s arm may require an extra-large adult cuff.

Not so at kiosks. Most have just one fixed-size cuff that fits arms of only a certain size. The blood pressure reading is reliable only if the user’s arm is within the range that has been validated for that cuff size. Moreover, not all kiosks have the same size cuff. There is no such thing as a “standard” cuff to fit a “standard” arm.

If the cuff doesn’t fit your arm properly, your reading won’t be accurate.

“Different kiosks have different cuff sizes that will fit different people -- so it’s important to know the circumference of your upper arm because not all devices are alike,” says Stephen Browning, a biomedical engineer at FDA. “Many people will be outside the arm size range for a particular kiosk, and the information from that kiosk won’t be reliable for them.”

Other factors, including how someone uses a device, might cause an inaccurate reading. “The user might not have placed the cuff on his arm properly or might not be sitting properly. These things will affect accuracy,” Herbertson says.

That’s why people shouldn’t overreact to any one reading from a kiosk.

“Hypertension isn’t diagnosed solely based on one reading. Inaccurate blood pressure measurements can lead to the misdiagnosis of hypertension or hypotension (low blood pressure), and people who need medical care might not seek it because they are misled by those inaccurate readings,” Browning says.

“Next time you see your doctor, get his or her opinion about whether blood pressure kiosks are right for you and if so, learn to use them properly—using the right size cuff so you can get accurate readings,” Herbertson advises.

What to do

Consumers use kiosks for various reasons. They might have been advised by their doctor to monitor changes to their health. They may be concerned about hypertension. Or they may just be curious about their blood pressure.

Health care providers diagnose hypertension based on several blood pressure measurements over a period of time. Remember that one measurement -- from a kiosk or other device -- doesn’t a diagnosis make.

Like your heart rate, your blood pressure can change quickly. It might be higher during a stressful meeting, after a brisk walk or because you’re sick. Those variations are normal. That’s why people with hypertension monitor their blood pressure frequently. And health care providers often depend on the patient’s own readings to augment the reading in a doctor’s office, so kiosks can be useful in many circumstances.

Although blood pressure kiosks have their limitations, they can provide valuable information when used properly and under the guidance of a health care provider.

Among the types of medication people take for high blood pressure are beta blockers, which are a class of drugs that reduce stress levels within the body.

If you take one, you might be reducing your risk of Alzheimer's disease. A study involving autopsies of 774 elderly Japanese-American men, most of whom had suffered from high blood pressure, yielded interesting results.

Only 15 percent of the men had been taking beta blockers for their high blood pressure. Their autopsies revealed they suffered the least amount of brain damage.

The researchers found that all types of blood pressure treatments were clearly better than no treatment. However, men who had received beta blockers as their only blood pressure medication had fewer abnormalities in their brains compared with those who had not been treated for their hypertension, or who had received other blood pressure medications.

Less brain shrinkage

The brains of participants who had received beta blockers plus other medications showed an intermediate reduction in numbers of brain abnormalities. Study participants who had taken beta blockers alone or in combination with another blood pressure medication had significantly less shrinkage in their brains.

“With the number of people with Alzheimer’s disease expected to grow significantly as our population ages, it is increasingly important to identify factors that could delay or prevent the disease,” said study author Lon White, MD, of the Pacific Health Research and Education Institute in Honolulu. “These results are exciting, especially since beta blockers are a common treatment for high blood pressure.”

Beta blockers questioned as blood pressure treatment

In October researchers at the NYU Langone Medical Center questioned whether beta blockers were an effective means of combating high blood pressure. They studied patients taking the drugs and concluded they weren't helping -- at least they weren't lowering blood pressure.

Sripal Bangalore, MD, assistant professor in the Department of Medicine and leader of the research team, suggested the current use of beta blockers to treat high blood pressure is based on old studies.

“Our results found none of the patient populations studied showed benefit from taking beta-blockers, including patients with a history of heart attack,” Bangalore said in October, when his study was released. “This is concerning in light of current treatment patterns and reveals a need for more education among practitioners who treat patients at risk for heart attack and stroke.”

This latest study, however, supported by the National Institutes of Health, might have found an additional use for the drugs. But beta blockers are known to have side effects, which include increases in cholesterol levels, weight gain, upset stomach and headaches.

If you think you are at risk of developing Alzheimer's disease you should discuss beta blockers with your doctor to determine if it is medication you should be taking.

It isn't just older folks who should be worried.

New research in the American Heart Association journal Hypertension finds the risk of elevated blood pressure among children and adolescents rose 27 percent during a thirteen-year period.

The culprits may be higher body mass, larger waistlines and eating too much sodium or salt.

High blood pressure is a risk factor for stroke, heart disease and kidney failure and accounts for about 350,000 preventable deaths a year in the U.S.

"High blood pressure is dangerous in part because many people don't know they have it," said Bernard Rosner, Ph.D., lead author of the study and professor of medicine at Harvard Medical School. "It's a very sneaky thing. Blood pressure has to be measured regularly to keep on top of it."

What's 'normal?'

In adults age 20 and older, blood pressure should normally be less than 120/80 mm Hg. However, among children and teens blood pressure norms vary according to age, sex and height.

While the researchers noted "elevated" readings, the children could not be called hypertensive because blood pressure readings must be high three times in a row for an official diagnosis.

Researchers compared more than 3,200 children ages 8-17 in the National Health and Nutrition Examination Survey (NHANES) III in 1988-1994 with more than 8,300 in NHANES in 1999-2008. They accounted for differences between the two groups in age, sex, race/ethnicity, body mass, waistline and sodium intake.

The findings

Researchers found:

• Boys were more likely to have elevated blood pressure, but the rate increased more markedly in girls from the first study to the second.
• More children were overweight in the second study, and both sexes -- especially girls -- had bigger waistlines.
• Children whose body mass or waistline measurements were in the top 25 percent for their age group were about twice as likely to have elevated blood pressure as children with measurements in the bottom 25 percent.
• Black children had a 28 percent higher risk of elevated blood pressure than non-Hispanic white kids.
• In both studies, children with the greatest sodium intake were 36 percent more likely than those with the lowest intake to have elevated blood pressure.
• More than 80 percent of children in both studies had a daily sodium intake above 2,300 milligrams; however, fewer children in the later study had an intake above 3,450 milligrams.

"Everyone expects sodium intake will continue to go up," Rosner said. "It seems there's been a little bit of listening to dietary recommendations, but not a lot."

What to do

Americans eat an average 3,400 milligrams of sodium daily -- more than twice the 1,500 or less that the American Heart Association recommends. Two-thirds of sodium intake is from store-bought foods and one-quarter from restaurant offerings.

Studies have linked excessive sodium in the diet to high blood pressure, and have suggested reducing sodium intake in children's and adolescents' can lower average systolic (top number) blood pressure by 1.2 mm Hg and average diastolic (bottom number) pressure 1.3 mm Hg.

All of a sudden, the medical community is second guessing the recent low benchmarks for “safe” blood pressure. In short, some are suggesting “the lower the better” approach might not be the right one after all.

The latest questions appear in a study published in the online edition of JAMA Internal Medicine. Researchers at Wake Forest Baptist Medical Center report that lowering systolic blood pressure below 120 does not appear to provide additional benefit for patients.

Systolic pressure is the top number in a standard blood pressure reading such as 120/80.

“Frequently we treat patients’ blood pressure to the lowest it will go, thinking that is what’s best,” said Carlos J. Rodriguez, M.D., associate professor of public health sciences at Wake Forest Baptist and lead author of the study.

Lower not necessarily better

But the researchers found that pushing blood pressures to the lowest levels possible didn't provide any benefit to patients with risk of dangerous events like heart attack, heart failure and stroke.

“This calls into question the notion that lower is better,” Rodriquez said.

Previous studies had claimed a progressive rise in heart disease risk as systolic blood pressure (SBP) rose above 115. According to the Mayo Clinic, normal blood pressure is below 120/80, which is often difficult to achieve without medication.

However, that's a relatively recent change. Until 2003 most doctors considered 120/80 an ideal blood pressure and a systolic reading up to 140 to be satisfactory.

But a report that year from the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure warned that blood pressure needed to be lower. It said systolic pressure as low as 120 might be risky. For millions of patients, that meant taking medication.

Drug industry influence?

It has to be asked what role the pharmaceutical companies might have played in developing these new standards. A 2005 investigation by The Seattle Times alleged 9 of the 11 authors of the new guidelines had drug company ties.

A new panel on hypertension issued new guidelines last December, suggesting patients over 60 were fine with a blood pressure reading of 150/90. Blood pressure goals were also eased for adults with diabetes and kidney disease.

In March researchers at Duke University ran an analysis and determined that an estimated 5.8 million adults no longer needed blood pressure medicine under the new guidelines.

Controversial

“Raising the target in older adults is controversial, and not all experts agree with this new recommendation,” said lead author Ann Marie Navar-Boggan, a cardiology fellow at Duke University School of Medicine. “In this study, we wanted to determine the number of adults affected by these changes.”

Based on their study, the Duke researchers estimated the proportion of U.S. adults in need of hypertension treatment would decrease from 40.6% under the old guidelines to 31.7% under the new recommendations, resulting in a pretty big hit for drug companies.

More bad news for drug companies

The new Wake Forest study is likely to be seen as more bad news in the pharmaceutical industry. It found that among people with high blood pressure, once SBP is below 140, lowering it below 120 did not reduce heart risks.

“Our study found that the optimal blood pressure range for people with hypertension is 120-139, which significantly reduces the risk of stroke, heart attack or heart failure,” Rodriguez said. “These findings suggest that you don’t need to go lower than that to have the benefits.”

If you are currently taking medication for high blood pressure, you should continue to do so. Never make changes in your medication based on news stories. However, you should discuss these new guidelines with your healthcare provider for advice about whether you need to stay on the medication.

"These results provide no evidence to suggest that individuals concerned about the development of HBP (high blood pressure) should avoid dietary protein. Rather, protein intake may play a role in the long-term prevention of HBP," said Lynn Moore, associate professor of medicine at the Boston University School of Medicine. "This growing body of research on the vascular benefits of protein, including this study, suggest we need to revisit optimal protein intake for optimal heart health," she added.

In the latest study, published in the American Journal of Hypertension, researchers found participants consuming the highest amount of protein (an average of 100 g protein/day) had a 40% lower risk of having high blood pressure compared to the lowest intake level.

The researchers analyzed protein intakes of healthy participants from the Framingham Offspring Study and followed them for development of high blood pressure over an 11-year period.

Overweight and normal

They found that adults who consumed more protein, whether from animal or plant sources, had statistically significantly lower systolic blood pressure and diastolic blood pressure levels after four years of follow-up. In general, these beneficial effects were evident for both overweight and normal weight individuals.

They also found that consuming more dietary protein was associated with lower long-term risks for HBP. When the diet also was characterized by higher intakes of fiber, higher protein intakes led to 40%–60% reductions in risk of HBP.

One of three U.S. adults has hypertension and 78.6 million are clinically obese, a risk factor for the development of hypertension. Because of the strain that it puts on blood vessel walls, High blood pressure is one of the most common risk factors of stroke and an accelerator of multiple forms of heart disease, especially when paired with excess body weight.

Hypertension, or high blood pressure, is called "the silent killer." Elevated blood pressure can eventually lead to heart attack and stroke, and millions of people with hypertension don't know it.

There is very effective medication to control blood pressure -- and a healthy lifestyle also helps -- but first you have to know that your blood pressure is too high.

As we first reported back in early December, doctors have begun to worry about what they call "masked hypertension." A patient goes to the doctor and his blood pressure reading is a perfectly acceptable 129/82.

But then he goes about his daily life -- going to work, picking up the kids, cleaning out the garage, and while he's doing all that his blood pressure might be an unhealthy 147/96. He doesn't know, of course, because he doesn't have a blood pressure cuff at home to measure it.

Numbers are alarming

Researchers at Stony Brook and Columbia universities have studied this phenomenon by attaching 24-hour ambulatory blood pressure monitors to subjects in their study. They now say that not only is the condition real, the numbers associated with it are alarming.

They found 12.3% of people display a normal blood pressure reading in the clinic, are not taking blood pressure lowering medicines, have never had a heart attack or stroke, but have high blood pressure during their daily activities. This amounts to about one in eight adults over age 21 -- approximately 17.1 million people in the U.S.

Lead investigator Joseph Schwartz of Stony Brook says the study is breaking new ground in estimating the size of the problem. He says it could lead to new guidelines to help identify patients with high blood pressure and improve hypertension preventive methods.

What to do

Until then, it is helpful to know the hypertension risk factors. People over age 50 are at risk of developing hypertension. So are those who are overweight or obese, or have a sedentary lifestyle with little physical exercise.

Diet can also be a big risk factor. Eating unhealthy foods, especially those high in sodium, can increase the risk for hypertension. African-Americans are at a higher risk than other races.

If you think you might fall into one of those risk categories, consider investing in a home blood pressure monitoring cuff and learn how to properly use it.

Measuring your blood pressure two or three times a week, at different times of the day, might let you know if you are suffering from "masked hypertension," even though your readings at the doctor's office look just fine.