Blood pressure — especially that top number — should get more
of our attention.
Maybe your blood pressure has been normal for as long as you can
remember, but that doesn't mean you should let it slip beneath
your health radar. The older we get, the greater our chances of
developing high blood pressure (also known as hypertension). Even
if you don't have high blood pressure by age 55, your chances of
developing it eventually are 90%. According to a report from the
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
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.
The Framingham Heart Study, for example, showed that systolic
blood pressure alone identified 91% of people who needed
treatment, while diastolic pressure identified only 22% of those
needing treatment. Other research has demonstrated that treating
high systolic pressure cuts the risk of stroke in people ages 60
and over, even when diastolic pressure is normal.
In 2008, three hypertension experts writing in The
Lancet proposed that the systolic reading be the only blood
pressure measurement used in tracking and diagnosing hypertension
in people over age 50. That proposal requires more research, but
there's no question that systolic pressure should be front and
center at midlife and beyond. 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. (See the graph, "Age and
isolated systolic hypertension.") 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
Age and isolated systolic hypertension
Isolated systolic hypertension is the most common form of
hypertension in people ages 50 and over.
Why isolated systolic hypertension?
Certain medical conditions can cause or contribute to isolated
systolic hypertension. These include anemia, an overactive
thyroid or adrenal gland, a malfunctioning aortic valve, kidney
disease, and even obstructive sleep apnea. But usually it results
from age-related stiffening of the large arteries.
Blood pressure reflects both the amount of blood the heart pumps
out every minute (cardiac output) and the pressure the walls of
the arteries exert on the flowing blood (arterial resistance). A
healthy artery can expand as blood surges through it and return
to its original shape when the blood flow ebbs. As we age, our
arteries tend to lose their elasticity and therefore their
capacity to accommodate surges of blood.
Age-related changes, some at the cellular level, also promote the
accumulation of fatty deposits (plaque) on the inside of the
arterial walls. These changes contribute to the artery-clogging
process known as atherosclerosis (hardening of the arteries).
Plaque accumulation reduces arterial resiliency and stimulates
other processes that further arterial thickening and rigidity.
The less flexible the arteries, the greater the arterial
resistance — and the harder the heart has to work to pump blood.
As artery walls stiffen, diastolic blood pressure tends to drop,
while systolic pressure rises. Diastolic pressure usually levels
off or falls off after age 50, but systolic pressure continues to
increase throughout life.
What does your clinician hear during a blood pressure
Blood pressure is measured in millimeters (mm) of mercury
(Hg) because the traditional measuring device, called a
sphygmomanometer, uses a mercury-filled glass column
marked in millimeters. A rubber tube connects the column
to an arm cuff. As the cuff is inflated or deflated,
mercury rises and falls within the column.
To take your blood pressure, the clinician wraps the cuff
around your upper arm, centering an air bladder inside
the cuff over the brachial artery, which runs along the
inner arm. She or he rapidly inflates the cuff by
squeezing a rubber bulb, and listens to the sounds in the
brachial artery with a stethoscope.
When the pressure inside the cuff is greater than the
pressure generated by the heart's contractions, the cuff
squeezes the brachial artery shut, and no blood gets
through that part of the artery. There's silence in the
stethoscope. Air is then slowly released from the cuff.
When the pressure in the cuff is equal to the pressure
generated by the heart muscle as it contracts, pulses of
blood begin to get past the cuff. At that point, the
clinician will hear a steady thump that indicates
As the pressure in the cuff continues falling, blood
flows more easily past the cuff, and the thumping grows
fainter. Once the cuff pressure drops below the pressure
in the artery during the resting phase between
heartbeats, the thumping sound disappears. This indicates
What's gender got to do with it?
Up to about age 55, women have a lower incidence of hypertension
than men do, but after that, our blood pressure tends to rise
more sharply than men's — especially systolic pressure. Hormones
may be part of the story. There is some evidence that estrogen
protects women against hypertension. Animal studies suggest that
it prevents arterial stiffening and vulnerability to
atherosclerosis, though that hasn't been proven in humans.
Still, it's unclear how menopause and the resulting decline in
estrogen affect blood pressure. Longitudinal studies (those that
follow health changes over time) haven't shown an increase in
blood pressure during the menopausal transition. Other research
suggests that even after adjusting for factors such as age and
weight, postmenopausal women are twice as likely as premenopausal
women to have high blood pressure. In the Third National Health
and Nutrition Examination Survey, the rise in systolic blood
pressure was steeper in postmenopausal women, up to age 60. So at
least some of the increase in blood pressure (mainly systolic)
could be related to menopause. But it's important to remember
that many other factors are in play as well.
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. To get an idea of the impact these changes can
have on systolic blood pressure, see the chart, "Effects of
lifestyle changes on systolic blood pressure." Regular exercise
is especially effective. It increases the heart's pumping
capacity in several ways and also improves vessel elasticity and
Effects of lifestyle changes on systolic blood pressure
Effect on systolic blood pressure (SBP)
If you're heavy, every 2 pounds of weight lost can reduce
SBP by 1 mm Hg.
DASH eating plan*
A diet rich in fruits, vegetables, and low-fat dairy
products, and low in both saturated and total fat, can
reduce SBP by 8 to 14 mm Hg.
Reduced salt intake
Limiting daily salt intake to 6 grams (about 1 teaspoon)
of table salt (sodium chloride) can reduce SBP by 2 to 8
30 minutes of brisk walking or other aerobic activity
most days of the week can reduce SBP by 4 to 9 mm Hg.
One drink a day in women may lower SBP by 2 to 4 mm Hg.
*You can download information about the DASH diet,
including recipes and eating plans, from the National
Heart, Lung, and Blood Institute, at
Source: Adapted from The Seventh Report of the Joint
National Committee on Prevention, Detection, Evaluation,
and Treatment of High Blood Pressure, available at
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
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
To learn more about how to monitor your blood pressure at home,
go to /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.
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