High Blood Pressure: The Invisible Health Risk

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High Blood Pressure: The Invisible Health Risk

It has no symptoms, but kills 50,000 Americans a year.

By Gina Shaw
WebMD Feature

Reviewed By Charlotte Grayson

It's 2005: Do you know what your blood pressure should be? Within the last two years, a number of new studies have led doctors to rethink their conclusions about what defines high blood pressure (hint: it's lower than you think), and the best approaches to treating this deceptively symptom-free disease.

More than 50 million Americans aged 6 and older now have high blood pressure, also called hypertension. Only one in three is keeping their blood pressure under control with medication, lifestyle measures, or both. You could be one of them and not even know it: 30% of people with hypertension have no idea they have it.

High blood pressure is easy to ignore, because it has no symptoms other than numbers on a blood pressure cuff. But its silence is deadly. Hypertension killed nearly 50,000 Americans in 2001, and the rates continue to rise, according to the American Heart Association. Uncontrolled high blood pressure puts you at risk of heart attack, stroke, heart failure, kidney disease, and a host of other problems.

Think You're Safe? Check Again

Within the last two years, we've learned that blood pressure levels we once thought were "safe" may not be. "We used to say that risky blood pressure levels didn't begin until around 140/90, but it's now become clear from more recent studies that the risk probably begins somewhere between 115 to 120 over 75 to 80," says Elijah Saunders MD, professor of medicine and head of the section of hypertension in the division of cardiology at the University of Maryland School of Medicine in Baltimore. "So we now use 120/80 as a round figure for where risk begins."

Doctors have coined the term "prehypertension" to describe people whose blood pressure is above 120/80, but not yet at 140/90. "We believe these people are at higher risk, and studies show that they do have lots of the same hypertension complications that we thought didn't occur until blood pressure was much higher," Saunders says.

Recent studies funded by the Agency for Health Care Research and Quality estimate that as many as two-thirds of people between the ages of 45 and 64 might have prehypertension. That the rate is significantly higher for those 65 and over. If you have other complicating conditions -- particularly diabetes and kidney problems -- along with prehypertension, doctors now recommend treating your blood pressure aggressively with drugs to help lower your risk of heart attack or stroke.

Quick GuideHow to Lower Blood Pressure: Exercise Tips

How to Lower Blood Pressure: Exercise Tips

What if only the top number is high? That's your systolic pressure, and research now shows us that it's more important in determining whether or not you have hypertension. If your systolic pressure is high but your diastolic pressure is normal, you still have hypertension and you're still at risk. "High systolic pressure is a very powerful risk factor for cardiovascular complications," says Saunders. "It's also responsible for most uncontrolled hypertension."

Change Your Blood Pressure, Change Your Life

We don't know exactly what causes high blood pressure, although we do know that family history plays a role. You can't do anything about your genes, or about getting older, or about being black -- all added risk factors for hypertension (hypertension affects about 40% of the black population, and it's more likely to show up earlier in life and be more severe than in whites). But you're also not doing yourself any favors if your pantry is stocked with potato chips and other salty treats, if you drink too much alcohol, and if the last time you worked up a sweat was in anticipation of the Survivor finale.

The good news: all that can be changed. One of the best ways to control hypertension is -- surprise! -- with healthy diet and exercise, the same things that help to prevent so many other diseases and disorders.

The gold standard of hypertension eating plans is the DASH diet (Dietary Approaches to Stop Hypertension), endorsed by the National Heart, Lung, and Blood Institute and clinically proven to reduce blood pressure. This low-fat diet calls for:

  • 7-8 servings a day of high-fiber grains
  • 4-5 servings a day of fruits
  • 4-5 servings a day of vegetables
  • 3 servings a day of low-fat dairy
  • 2 or fewer servings a day of meat, poultry, or fish
  • 4-5 servings a week of beans, nuts, or seeds

Another diet -- DASH-Sodium -- calls for reducing salt to 1,500 mg a day (about 2/3 teaspoon). Both diets help people lower their blood pressure, but studies indicate that the DASH-Sodium plan lowers blood pressure the most.

The American Heart Association reports that blood pressure can fall significantly after only 12 weeks of either a 1,200-calorie diet or an hour a day of aerobic exercise. Indeed, they report that in recent studies, aerobic exercise alone reduces both weight and blood pressure more effectively than diet alone. But your best bet: Improve your activity level and your eating habits. Even if you don't have high blood pressure now, healthy habits today will help prevent hypertension tomorrow.

Medical Treatment Options for High Blood Pressure

High blood pressure can't always be completely controlled with a healthy lifestyle. And some people, especially those with additional complications, such as diabetes and kidney disease, urgently need to lower blood pressure to safe levels. That's where medication comes in.

There's a long list of drugs that are commonly used to lower blood pressure and help prevent heart attack and stroke, including ACE inhibitors, beta-blockers, calcium channel blockers, and diuretics. Recently, they've been joined by the latest, and possibly most exciting, class of hypertension drugs: angiotensin receptor blockers, or ARBs. In early December, an international trial comparing blood pressure-lowering treatments was stopped early when patients taking an ARB combined with a calcium channel blocker showed significant cardiovascular benefits (such as reduced rates of heart attack and stroke) compared with those taking an older combination of a beta-blocker and a diuretic.

Patients with diabetes, kidney disease, and some types of heart disease also appear to get greater cardiovascular protection from ACE inhibitors and ARBs than from other blood pressure-lowering drugs. "In individuals at high risk of heart attack and stroke, we've seen that these particular drugs provide additional protection," says Saunders. The National Kidney Foundation and the American Diabetes Association both now recommend either an ARB or an ACE inhibitor as the initial treatment of choice to reduce blood pressure for people with diabetes, kidney disease, or both.

As often happens with the latest and greatest drugs, ARBs are more expensive than ACE inhibitors, which have been around longer. But they have one advantage: Nearly 5% to 10% of patients taking ACE inhibitors will develop a cough. Since ARBs don't stimulate the chemicals in the body that's likely to cause the cough, your chance of that side effect is minimal. If you can't tolerate an ACE inhibitor for that reason, your doctor may recommend switching to an ARB.

Doctors have also learned that starting combination therapies early in treatment for hypertension is often the best approach. "Up until recently, we were teaching doctors to try one drug and then add on another, but studies have found that two-thirds of hypertensive patients require two drugs to get their blood pressure to go down," says Saunders. "So now, the recommendation is to consider using two drugs from the start."

The combination can include any two drugs that are compatible and that operate on different mechanisms; the most common combination would be an ACE inhibitor or an ARB with a diuretic, which helps the other drug to work more effectively.

But some combinations may pose a problem. Recent research from the large Women's Health Initiative study showed that diuretics combined with calcium channel blockers appeared to double the risk of heart attack in older women. Scientists caution that there are significant limitations to this study, and that more research is needed. In the meantime, be sure to ask your doctor what the best combination is for you.

Quick GuideHow to Lower Blood Pressure: Exercise Tips

How to Lower Blood Pressure: Exercise Tips

What's Next in Treating High Blood Pressure?

Researchers are now studying different classes of drugs that might help reduce high blood pressure. "Blood pressure has multiple mechanisms, and most drugs that aim to reduce it either concentrate on dilating the blood vessels or on blocking salt and water retention," says Saunders. "Basic scientists are now experimenting with new compounds that target other elements of the cardiovascular system to help reduce blood pressure."

Many of these potential new targets, Saunders says, involve hormones -- not sex hormones like estrogen or testosterone, but hormones like renin and angiotensin, which play a role in helping to control blood pressure. "Scientists are looking at whether drugs that block these hormones will help to control the blood-regulating mechanisms that affect blood pressure," he says.

There are many health risk factors in your life that you can't control, but hypertension isn't one of them. With a combination of a healthy lifestyle and medication when needed, you can keep your blood pressure numbers in the safe zone and your cardiovascular system healthy.

Published January 2005.


SOURCES: Elijah Saunders, MD, professor of medicine, University of Maryland School of Medicine, Baltimore, Md. American Heart Association, Dallas. National Heart, Lung, and Blood Institute, Bethesda, Md. Agency for Health Care Research and Quality, Washington.

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Reviewed on 1/31/2005 9:15:36 AM

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