On this page:
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What
is high blood pressure?
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How
does high blood pressure hurt my
kidneys?
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How
will I know whether I have high
blood pressure?
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How
will I know whether I have kidney
damage?
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How
can I prevent high blood pressure
from damaging my kidneys?
-
Are
there medicines that can help?
-
What
groups are at risk for kidney
failure related to high blood
pressure?
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Hope
Through Research
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For
More Information
Your kidneys play a
key role in keeping your blood pressure
in a healthy range, and blood pressure,
in turn, can affect the health of your
kidneys. High blood pressure, also
called hypertension, can damage the
kidneys.
What is
high blood pressure?
Blood pressure
measures the force of blood against the
walls of your blood vessels. Blood
pressure that remains high over time is
called hypertension. Extra fluid in your
body increases the amount of fluid in
your blood vessels and makes your blood
pressure higher. Narrow or clogged blood
vessels also raise your blood pressure.
If you have high
blood pressure, see your doctor
regularly.
Hypertension can result from too much
fluid in normal blood vessels or from
normal fluid in narrow blood vessels.
How does
high blood pressure hurt my kidneys?
High blood pressure
makes your heart work harder and, over
time, can damage blood vessels
throughout your body. If the blood
vessels in your kidneys are damaged,
they may stop removing wastes and extra
fluid from your body. The extra fluid in
your blood vessels may then raise blood
pressure even more. It's a dangerous
cycle.
High blood pressure
is one of the leading causes of kidney
failure, also commonly called end-stage
renal disease (ESRD). People with kidney
failure must either receive a kidney
transplant or go on dialysis. Every
year, high blood pressure causes more
than 25,000 new cases of kidney failure
in the United States.
How will
I know whether I have high blood
pressure?
Most people with high
blood pressure have no symptoms. The
only way to know whether your blood
pressure is high is to have a health
professional measure it with a blood
pressure cuff. The result is expressed
as two numbers. The top number, which is
called the systolic pressure, represents
the pressure when your heart is beating.
The bottom number, which is called the
diastolic pressure, shows the pressure
when your heart is resting between
beats. Your blood pressure is considered
normal if it stays below 120/80
(expressed as "120 over 80"). People
with a systolic blood pressure of 120 to
139 or a diastolic blood pressure of 80
to 89 are considered prehypertensive and
should adopt health-promoting lifestyle
changes to prevent diseases of the heart
and blood vessels. If your systolic
blood pressure is consistently 140 or
higher or your diastolic pressure is 90
or higher, you have high blood pressure
and should talk with your doctor about
the best ways to lower it.
How will
I know whether I have kidney damage?
Kidney damage, like
hypertension, can be unnoticeable and
detected only through medical tests.
Blood tests will show whether your
kidneys are removing wastes efficiently.
Your doctor should order tests to
measure your serum creatinine. Having
too much creatinine in your blood is a
sign that you have kidney damage. The
doctor should use the serum creatinine
to estimate the main kidney function
called glomerular filtration rate, or
GFR.
Another sign is
proteinuria, or protein in your
urine. Proteinuria has also been shown
to be associated with heart disease and
damaged blood vessels. (For more
information, see the fact sheet Proteinuria from the
National Institute of Diabetes and
Digestive and Kidney Diseases (NIDDK).)
How can I
prevent high blood pressure from
damaging my kidneys?
If you have kidney
damage, you should keep your blood
pressure below 130/80. The National
Heart, Lung, and Blood Institute
(NHLBI), one of the National Institutes
of Health (NIH), recommends that people
with kidney disease use whatever therapy
is necessary, including lifestyle
changes and medicines, to keep their
blood pressure below 130/80.
How can I
control my blood pressure?
NHLBI has found that five
lifestyle changes can help
control blood pressure:
-
Maintain your weight at a
level close to normal.
Choose fruits, vegetables,
grains, and low-fat dairy
foods.
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Limit your daily sodium
(salt) intake to 2,000
milligrams or lower if you
already have high blood
pressure. Read nutrition
labels on packaged foods to
learn how much sodium is in
one serving. Keep a sodium
diary.
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Get plenty of exercise,
which means at least 30
minutes of moderate
activity, such as walking,
most days of the week.
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Avoid consuming too much
alcohol. Men should limit
consumption to two drinks
(two 12-ounce servings of
beer or two 5-ounce
servings of wine or
two 1.5-ounce servings of
"hard" liquor) a day. Women
should have no more than a
single serving on a given
day because metabolic
differences make women more
susceptible to the effects
of alcohol.
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Limit caffeine intake.
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Are there
medicines that can help?
Many people need
medicine to control high blood pressure.
Two groups of medications called ACE
(angiotensin-converting enzyme)
inhibitors and ARBs (angiotensin
receptor blockers) lower blood pressure
and have an added protective effect on
the kidney in people with diabetes.
Additional studies have shown that ACE
inhibitors and ARBs also reduce
proteinuria and slow the progression of
kidney damage in people who do not have
diabetes. You may need to take a
combination of two or more blood
pressure medicines to stay below 130/80.
Your doctor may also prescribe a
diuretic in addition to your ACE
inhibitor or ARB. Diuretics are also
called "water pills" because they help
you urinate and get rid of excess fluid
in your body.
What
groups are at risk for kidney failure
related to high blood pressure?
All racial groups
have some risk of developing kidney
failure from high blood pressure.
African Americans, however, are more
likely than Caucasions to have high
blood pressure and to develop kidney
problems from it?even when their blood
pressure is only mildly elevated. In
fact, African Americans are six times
more likely than Caucasions to develop
hypertension-related kidney failure.
People with diabetes
also have a substantially increased risk
for developing kidney failure. People
who are at risk both because of their
race and because of diabetes should have
early management of high blood pressure.
The National
Institute of Diabetes and Digestive and
Kidney Diseases (NIDDK), also part of
NIH, sponsored the African American
Study of Kidney Disease and Hypertension
(AASK) to find effective ways to prevent
high blood pressure and kidney failure
in this population. The results,
released in 2003, showed that an ACE
inhibitor was better at slowing the
progression of kidney disease in African
Americans than either of two other
drugs.
Hope
Through Research
In recent years,
researchers have learned a great deal
about kidney disease. NIDDK sponsors
several programs aimed at understanding
kidney failure and finding treatments to
stop its progression.
NIDDK's Division of
Kidney, Urologic, and Hematologic
Diseases supports basic research into
normal kidney function and the diseases
that impair normal function at the
cellular and molecular levels, including
diabetes, high blood pressure,
glomerulonephritis, and polycystic
kidney disease.
