Courtesy of Harvard Health Letters
September 15, 2009
According to a report from the U.S. government's Agency for Healthcare Research and Quality, more than 25 million women, most over age 45, were treated for high blood pressure in 2006. That makes it the most common condition for which women seek treatment.
Uncontrolled hypertension can damage the lining of the arteries, increasing the risk of cardiovascular disease (in particular, heart disease and stroke), which is the leading cause of death among women in the United States. High blood pressure can also impair vision, cause kidney failure, and contribute to dementia. Yet its symptoms are subtle and largely unnoticeable until it has caused considerable damage.
Clinicians once assumed that high blood pressure was a normal part of aging and rarely treated it in older people. But now, several large clinical trials have shown that in people ages 60 and over (including those over the age of 80), treatment reduces the incidence of strokes and other cardiovascular events. Fortunately, there are many ways to prevent or control high blood pressure.
The two numbers in a blood pressure reading represent the peak pressure reached in the heart's pumping cycle (the systolic pressure, the top number) and the lowest pressure during the resting phase of the cycle (the diastolic pressure, the bottom number). The result is measured in millimeters of mercury (mm Hg), and expressed as systolic over diastolic -- for example, 110/80 mm Hg.
You have high blood pressure if your systolic pressure is 140 or above or your diastolic pressure is 90 or above, or both. Blood pressure naturally rises and falls throughout the day, so a single reading doesn't tell you much. What matters is the pattern over time. High blood pressure is diagnosed only if your clinician finds a consistently elevated level over several months.
Systolic and diastolic blood pressures tend to rise and fall together, especially in young and middle-aged adults, but diastolic pressure fluctuates less, and for that reason, clinicians used to focus on the diastolic reading. But since the 1990s, research has highlighted the importance of systolic pressure, especially in older adults.
In 2003, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure stated unequivocally that in people over age 50, an elevated systolic reading (140 mm Hg or higher) is a much more significant risk factor for cardiovascular disease than an elevated diastolic reading. Its conclusion was based on a large body of evidence.
By age 60, high blood pressure affects one out of every two people, and most have isolated systolic hypertension -- a systolic pressure of 140 or above with a normal (under 90) diastolic pressure.
Fortunately, that condition is treated like other forms of hypertension, with lifestyle changes and sometimes medications. If you have no complicating health problems, the goal is to reduce blood pressure to under 140/90 mm Hg. If you have diabetes or kidney disease, the target is under 130/80 mm Hg. However, diastolic pressure should not go below 60 mm Hg (or below 65 mm Hg in the very old or people with coronary artery disease).
Isolated systolic hypertension is the most common form of hypertension in people ages 50 and over.
WHAT TO DO
If you have isolated systolic hypertension, your clinician should run tests to rule out anemia and other medical conditions. She or he will also evaluate your cardiac risk factors, including body mass index and cholesterol levels, and check for hypertension-related damage to the eyes or kidneys.
The next step is to adopt healthier habits -- the cornerstone of prevention and treatment. That means losing excess weight, getting regular exercise (which can also help you lose weight), not smoking (and making sure you avoid others' smoke), reducing sodium (salt) intake, and eating plenty of fruits, vegetables, and whole grains. Regular exercise is especially effective. It increases the heart's pumping capacity in several ways and also improves vessel elasticity and function.
If you don't have diabetes or any damage to your heart, brain, kidneys, or eyes, lifestyle changes alone may be enough to bring high blood pressure down to normal.
If lifestyle changes alone don't get your systolic pressure under control, an antihypertensive drug should be added. There are many kinds of blood pressure medications, and which one is appropriate for you will depend on your particular situation.
If you have relatively mild hypertension and no complicating health problems, guidelines suggest starting with a thiazide diuretic (a "water pill"), which works in the kidneys to flush excess water and sodium from the body. If you have heart disease or diabetes, your clinician may recommend an angiotensin-converting enzyme (ACE) inhibitor or calcium-channel blocker -- both of which reduce blood pressure by relaxing blood vessels.
Because different kinds of drugs work in different ways, you may need to take two or more. Also, the same drug may have different side effects in different people. (For a more detailed list of high blood pressure medications, how they work, and their side effects, go to www.health.harvard.edu/womenextra.)
Once you've been diagnosed with hypertension, you should keep track of your blood pressure with a home monitoring device. You can buy one at a drugstore or medical specialty shop or on the Internet for as little as $50. The best type of home blood pressure monitor is oscillometric -- that is, it doesn't require a stethoscope -- and works with a cuff that fits on the upper arm. (Wrist and finger models are not recommended.) Bring the monitor to your clinician's office to check its accuracy and your technique.
To learn more about how to monitor your blood pressure at home, go to www.health.harvard.edu/womenextra. You can also watch a video demonstration at health.harvard.edu/128. For a downloadable blood pressure-tracking chart and other helpful tools, visit the American Heart Association's High Blood Pressure Web page at www.americanheart.org/HBP. -- Harvard
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