High pressure tactics

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GOOD MEDICINE

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45 million Americans are now considered "prehypertensive" and are at risk of cardiovascular damage. Lifestyle changes make a big difference — some more than others.

The e-mail from my twin sister was a wake-up call about the family curse. "I'm on blood-pressure medicine now," Maureen wrote.

Dad was prescribed blood-pressure pills 49 years ago, and still takes them every day. Mom joined him 20 years ago, and my older sister and brother have recently gone on medication.

So far, I'm the exception, but my blood pressure has been creeping upward to the point that on some days I'm within the "prehypertensive" category. That's the new designation set by the National Heart, Lung, and Blood Institute. Since research that arteries are damaged by blood pressure at levels lower than previously thought, the new "normal" is less than 120/80.

About 45 people who have blood pressure levels of 120-139/80-89 are in this new category. And the lifetime risk for developing hypertension is shockingly high for all Americans:

Those who don't have it at age 55 have a 90 percent risk of developing it.

Doctors blame 50 percent of high blood pressure on how people live day to day. (The rest is attributed to genetics.) With my family history, I decided to take action to lower my numbers to normal levels and then keep them there.

shed excess pounds
The most important thing you can to do to avoid high blood pressure is maintain your body weight within the ideal range, according to Thomas G. Pickering, M.D., director of the Behavioral Cardiovascular Health and Hypertension Program at Columbia-Presbyterian Medical Center in New York City.

That means keeping your body mass index under 25. BMI is a calculation of the appropriate weight for your height. A 5-foot-5-inch woman who weighs 150 has a BMI of 25. (To calculate your BMI, visit surgeongcncral.gov/topics/obesity/calltoaction/fact_advice .htm).

Why excess weight boosts pressure isn't certain. Pickering says one possibility is that the hormone leptin, produced by fat cells and thus in greater supply in some overweight people, may overstimulate the sympathetic nervous system, which regulates blood pressure. A rough rule of thumb is that two extra pounds gained may drive up pressure by one point.

But when weight goes down, even a little, so does blood pressure. According to a study in the August American Journal of Hypertension, people who lost 10 percent of their body weight reduced systolic pressure (the top number, which is a measure of arterial blood flow when the heart beats) by 4.3 points on average and diastolic pressure (the bottom number, a measure of arterial pressure between beats) by 3.8 points.

watch your diet
"About one-third of people are salt-sensitive," says Pickering. In these patients, salt, or sodium chloride, draws water into the bloodstream, and the extra volume of fluid raises blood pressure.

To determine if you're salt-sensitive, get your pressure measured while on a normal diet, and then restrict salt for a couple of months and have your pressure taken again, suggests Alice H. Lichtenstein, D.Sc., vice chair of the American Heart Association's nutrition committee.

To keep pressure within the normal range or reduce pressure that's inching up, the National Institutes of Health recommends an eating plan called DASH (Dietary Approaches to Stop Hypertension), which is described online at nhlbi.nih.gov/health/public/heart/hbp/dash/new_dash.pdf.

High in fruits and vegetables, grains and low-fat dairy products, the DASH plan includes menus that keep sodium intake at 2,400 milligrams, the upper limit suggested for everyone, and options restricting sodium to 1,500 milligrams for those who are sensitive to it.

To lower blood pressure it's also helpful to get adequate amounts of minerals such as potassium, magnesium and calcium, says Christian Dodge, N.D., a naturopathic physician at Bastyr University in Seattle. Fruits such as bananas, pears and oranges are rich in potassium, and magnesium is found in whole grains and green vegetables. Calcium is abundant in milk and yogurt.

move, move, move
Most experts suggest 30 minutes of moderate activity, such as walking two miles in 30 minutes, nearly every day. A study in the August 2003 American Journal of Hypertension quantifies it even more. Researchers assigned 207 subjects, all with high blood pressure but not yet on medication, to either a control group that did not work out or to one of four groups that exercised for 30 to 60 minutes, 61 to 90, 91 to 120 or more than 120 minutes a week for eight weeks.

All the exercise groups reduced systolic and diastolic pressures, but the greatest systolic reduction — about 12 points on average — was in the 61- to 90-minutes-a-week group. No greater systolic reductions were achieved with additional exercise. Diastolic pressure dropped about eight points on average for all groups.

Exactly how exercise lowers blood pressure isn't known. Pickering believes that exercise may have a beneficial effect on the sympathetic nervous system. In addition, working out helps people maintain a healthy weight, and that ultimately helps control blood pressure. Research by James O. Hill, Ph.D., of the National Weight Control Registry, found that most people who have lost at least 30 pounds — and kept the weight off for a year or more — exercised an hour a day.

what I did
I'm fortunate to have an internist, Richard Silverstein, M.D., who thinks a 50 percent chance of outwitting my genes is worth fighting for. He helped me map a strategy. Since my BMI was nearly 25, shedding pounds became a priority. Some people lose weight on the DASH diet, but I didn't, so Silverstein suggested I go to Weight Watchers. In two months, I dropped 16 pounds, and my BMI is now a healthy 22.

I'm a lifelong exerciser, getting in four to seven hours a week, so that habit just needs to be continued. Not hard to do, when I figure it's probably what's kept me off medication all this time. I measure my pressure at home about once a week, and it's come down since the weight loss. My last reading was 111/71. Before the weight loss, it was occasionally as high as 132/81. With luck and persistence, I'm hoping to avoid blood-pressure medication for many, and perhaps all, my years to come.

If your blood pressure spikes at the doctor's office, don't sweat it. The general consensus on this condition, known as "white-coat hypertension," is that it's a relatively low risk for hypertension-related stroke and heart attack, according to cardiologist Thomas Pickering, M.D.

In one study, people with mildly high blood pressure who ate about 3 ounces of dark chocolate every day for two weeks brought their blood pressure down a few points. Dark chocolate contains antioxidants that may protect against free-radical damage associated with heart disease. White chocolate, milk chocolate, or chocolate eaten with milk failed to achieve the same effect, according to a report in the Journal of the American Medical Association.

PHOTO (COLOR): Low-fat yogurt contains a healthy does a blood-pressure-controlling calcium.

PHOTO (COLOR)

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By Kathleen Doheny

Photographs by Jim Jordan

When lifestyle changes aren't enough
If weight loss and increased exercise don't bring down blood pressure within six months, or if blood pressure is dangerously high to begin with, there are several drugs that work in different ways to lower blood pressure. The majority of people end up on a combination of drugs, which nearly always includes a diuretic.

Daily diuretics or "water pills" work in the kidney to flush out excess water and sodium via the urine, reducing the amount of fluid in the blood so there's less pressure on blood-vessel walls.

ACE inhibitors prevent a substance known as angiotensin II from being formed, relaxing blood-vessel walls and reducing pressure.

Angiotensin II receptor blockers stop the action of angiotensin rather than its formation.

Beta blockers make the heart beat more slowly.

Calcium-channel blockers relax the blood-vessel muscles.

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