Hypertension, or high blood pressure, is
a condition commonly associated with narrowing of the arteries.
This causes blood to be pumped with excessive force against
the artery walls. It is a sign that the heart and blood vessels
are being overworked. Untreated, hypertension will cause the
heart to eventually overwork itself to the point where serious
damage can occur. For instance, the heart muscle can thicken
(hypertrophy) and function abnormally, or dilate and constrict
less forcefully (dilated cardiomyopathy). There may also be
injury to the brain, the eyes (retinopathy) and/or the kidneys
(nephropathy). Hypertensive patients are also at increased
risk of heart disease and stroke. Most cases of high blood
pressure have no cure, but the overwhelming majority can be
managed and controlled with diet and medication.
What is high blood pressure?
Hypertension is the medical term for high blood pressure.
Blood pressure is the measure of the force of the blood pushing
against the walls of the arteries — the blood vessels
that carry blood from the heart to the rest of the body. When
the heart contracts to pump out blood, pressure is highest.
This measurement is called the systolic pressure. After pumping,
the heart relaxes and pressure drops to its lowest point just
before a new beat. This measurement is called the diastolic
pressure.
The
measurement of an individual’s blood pressure is always
expressed as systolic pressure over diastolic pressure. For
example, normal blood pressure for adults is considered to
be in the range of 120/80 millimeters of mercury. Generally,
blood pressure above 140/90 is considered to be high for adults,
and blood pressure under 90/60 is considered to be low for
adults.
High blood pressure has been associated with a variety of
significant health risks, including an increased risk of heart
disease.
The cause of
about 90 to 95 percent of the cases of high blood pressure
is unknown. However the condition is easily detected and usually
controllable. Before age 55, a higher percentage of men than
women have high blood pressure. The percentage of women with
high blood pressure becomes slightly higher than men in the
55 to 74 age group. A higher percentage of women age 75 and
older have high blood pressure than men in the same age group.
High blood pressure is two to three times more common in women
taking birth control pills than those not taking them, especially
in women who are overweight or obese.
Is high blood pressure dangerous?
Over the past 10 years, the actual number of deaths
due to hypertension has increased by 40 percent. High blood
pressure contributes to 75 percent of all strokes and heart
attacks. According to data gathered from the Heart
Study, 50 percent of people who have a first heart attack
and two thirds of those who have a first stroke have blood
pressures higher than 160/95.
Unfortunately, many people with high blood pressure are unaware that they have the condition and do not seek treatment. Access to medical care also contributes to undertreatment of hypertension. Because of this, the rate of hypertension among the poor or uninsured may be underestimated because these groups often do not have adequate access to medical care.
Left untreated, high blood pressure will gradually continue
to rise even higher over the years, causing the heart to overwork
itself to the point where serious damage can occur. Untreated
hypertension also places other systems (e.g., circulation)
and organs (e.g., the kidneys) at greater risk of damage that
could lead to dysfunction or failure.
Hypertensive patients are at increased risk of the following:
- Heart disease (e.g., congestive heart failure, sudden
cardiac death, cardiomyopathy)
- Stroke
- Hardened arteries (atherosclerosis)
- Aneurysm (a weakness in the artery wall where it balloons
out to more than 1.5 times its normal size and is in danger
of rupturing), often resulting in sudden cardiac death
- Kidney failure
- Retinopathy (loss of vision)
The risk of developing one or more of these serious health
conditions increases as blood pressure rises. Hypertension
has often been called the “silent killer” because
mild to moderate levels usually go unnoticed by patients until
serious damage has already been done. To clarify the risk
factors, high blood pressure measurements for adults have
been ranked according to risk categories of increasing severity,
ranging from “normal” to “stage 4.” The
following categories apply to adults (age 18 and over) who
are not taking medicine for high blood pressure and do not
have a serious short-term illness:
| Stage |
Systolic Pressure |
|
Diastolic Pressure |
| Optimal * |
Under 120 |
AND |
Under 80 |
| Normal |
Under 130 |
AND |
Under 85 |
| High Normal |
130-139 |
OR |
85-89 |
| 1 |
140-159 |
OR |
90-99 |
| 2 |
160-179 |
OR |
100-109 |
| 3 |
180-209 |
OR |
110-119 |
| 4 |
210 or over |
OR |
120 or over |
Note: Optimal levels are with respect to heart disease risk.
Unusually low readings (below 90/60) can also negatively affect
heart health should be reported to a physician.
An important exception to the information listed above is
noted among patients with diabetes and/or kidney disease.
These patients will require treatment if their blood pressure
is above 130/80.
What are the symptoms of high blood pressure?
The majority of people with mild to moderate hypertension
cannot tell when their blood pressure is too high. In fact,
about one-third of hypertensive people are not aware of their
condition. Patients may experience chest pain (angina), shortness
of breath or other symptoms related to heart disease or underlying
damage.
Hypertension may cause any of the following:
- Fatigue
- Confusion
- Nausea or upset stomach
- Vision changes or problems
- Excessive sweating
- Paleness or redness of skin
- Nosebleeds
- Anxiety or nervousness
- Palpitations (strong, fast or obviously irregular heartbeat)
- Ringing or buzzing in ears
- Impotence
- Headache
- Dizziness
How is high blood pressure diagnosed?
When diagnosing hypertension, a physician will get a patient’s
full medical history. For example, the physician will ask
whether high blood pressure runs in the family and what the
patient’s dietary habits have been like (e.g., salt intake).
The physician will also give the patient a complete physical
examination, which will include checking the patient’s
blood pressure in both arms while standing and lying down.
In some cases, the physician may ask the patient to take his
or her own blood pressure at home and bring in a daily log
of blood pressure measurements. This strategy will help establish
the patient’s normal blood pressure pattern and to rule
out white coat hypertension (high blood pressure only while
in a physician’s office).
Blood pressure is measured by wrapping an arm cuff (attached
to a sphygmomanometer) snugly around the patient’s arm
and then using a stethoscope to listen to the brachial artery
located at the inside elbow on the same arm. The cuff is then
pumped full of air until circulation is very briefly cut off.
Then some air will be slowly let out of the device, loosening
the cuff’s grip on the arm and releasing the blood to
flow freely again. As the air is let out, the examiner watches
the numbers coming down on a simple monitor (sphygmomanometer)
and waits until he or she first hears the heartbeat. The number
at which that occurs is the systolic pressure. The examiner
remembers this as the numbers continue to come down on the
monitor and notes the number at which he or she last hears
the heartbeat. The number at which that occurs is the diastolic
pressure. Other blood pressure measurement devices may also
be used. Some use mercury to measure the sounds and others
employ digital readouts.
Reliable blood pressure monitors are also available if people
are interested in monitoring their own blood pressure and/or
that of their family members. When purchasing these monitors,
it is important to consult with a physician or a consumer
product rating agency regarding the reliability of home monitors.
Generally, arm cuff digital monitors are the easiest and most
reliable to use but should be periodically checked with a
mercury sphygmomanometer.
Following the physical examination, a number of tests will
often be ordered, which include the following:
- Urinalysis and various blood tests (e.g., electrolytes
and waste products) tests to rule out kidney disease.
- Electrocardiogram (EKG), which measures the heart’s
electrical activity. By analyzing the EKG results, a physician
can check for heart-related problems that could be associated
with high blood pressure (e.g., left ventricular hypertrophy).
- Echocardiogram, which uses sound waves to visualize the
structures and functions of the heart. This test is also
used to check for heart-related problems such as left ventricular
hypertrophy.
- Chest x-ray to rule out an enlarged heart.
Once a diagnosis has been made and serious problems (e.g.,
kidney disease) have been ruled out, then treatment can begin. However, very high blood pressure may
require additional testing to rule out an unusual cause. For
example, a renal Doppler sonogram or scan may be ordered to
evaluate for high blood pressure in the blood vessels of the
kidneys (renovascular hypertension). Also, a 24-hour urine
test may be needed to rule out an endocrine disorder, such
as Cushing disease or pheochromocytosis.
Hypertension may occur in either adults or children. Some
people may also be diagnosed with the opposite condition:
Low blood pressure (hypotension). Although some hypertensives
do not need to take medication as long as they can control
their risk factors (e.g., weight), most cases generally require
long-term treatment with medications.
How is high blood pressure treated?
Lifestyle changes can significantly improve a patient’s
blood pressure. Definite steps that can and should be taken
to lower and control blood pressure include:
-
Quitting smoking. This is perhaps the
most important thing a smoker can do to promote his or
her own health. Among many other side effects, smoking
elevates blood pressure.
-
Losing weight. Loss of weight in the
abdominal area can immediately reduce blood pressure and
helps to reduce the size of the heart. Weight loss accompanied
by salt restriction may allow mild hypertensives to reduce
or eliminate their need for medication.
-
Following the DASH diet. Well-controlled
studies have shown that people on the DASH diet for only
eight weeks experienced a significant reduction in blood
pressure.
- Getting adequate amounts of: vitamins and minerals. Studies
show that vitamin C protects normal levels of nitric oxide
— the substance that keeps arteries flexible. Vitamin
E and the B-vitamins may also be helpful. Also, adequate
intake of minerals such as potassium, magnesium and calcium
is thought by some experts to be even more helpful than
reducing salt intake for reducing blood pressure. Individuals
should consult with their physician before supplementing
their diet.
- Engaging in regular aerobic exercise. Exercising at least
three to four times per week is helpful for regulating high
blood pressure, keeping in mind that the regularity of the
exercise is more important than the intensity of the workout.
For example, studies have shown that Tai Chi (an ancient
Chinese workout involving slow relaxing movements) may lower
blood pressure almost as well as moderately intense aerobics.
Individuals should consult with their physician before starting
an exercise program.
- Limiting alcohol use to one drink per day for women and
two drinks per day for men. One drink is defined as one
6-ounce glass of wine per day, one 12-ounce beer or one
1-ounce shot of distilled spirits.
- Limiting salt intake to 2,000 milligrams (2 grams) of
sodium per day.
- Using stress management techniques. Emotional factors
may play important roles in the development of hypertension.
Studies have shown that cognitive-behavioral therapy, transcendental
meditation, active religious faith and participation in
church-related activities have all been associated with
reducing blood pressure to healthy levels. (Watching or
listening to religious services on radio or TV had no effect.)
- Having a pet may also lower blood pressure.
Women are also encouraged to discuss with their physicians
the increased risk of hypertension that results from taking
birth control pills, particularly if they are over the age
of 35. High
blood pressure is two to three times more common in women
taking birth control pills than those not taking them, especially
in women who are overweight or obese.
As hypertensive patients make these changes, they are often
encouraged to monitor their blood pressure at home, under
the guidance of their physician. In addition to these lifestyle
changes, patients are often prescribed blood pressure-reducing
medications.
These medications include the following:
-
Diuretics. Medications that promote the
formation of urine in the kidneys, causing the body to
flush out excess fluids and minerals, especially sodium.
These are often the first medications given to reduce
high blood pressure. Though commonly used, they may have
unwanted side effects, such as low potassium levels (hypokalemia).
- Alpha blockers and beta blockers. Medications that inhibit
alpha and beta receptors in various parts of the nervous
system, which slows the heart rate. This helps arteries
to relax, decreases the force of the heartbeat and reduces
blood pressure. Beta blockers are especially useful in patients
with heart disease.
- ACE inhibitors. These medications are types of vasodilators
that help to reduce blood pressure by inhibiting the substances
in the blood that cause blood vessels to constrict. Recent
studies suggest that this class of drugs may be superior
to others in preventing stroke, heart disease and kidney
disease in patients (especially diabetics) with risk factors
for vascular disease. They are also very useful in patients
with established heart disease.
- Angiotensin II receptor blockers (ARBs). This new class
of drugs is showing good results and great promise in reducing
hypertension-related complications. Although beta blockers,
ACE inhibitors and diuretics are currently used most often
in the treatment of hypertension, ARBs may be prescribed
more often in the future.
- Calcium channel blockers. These are types of vasodilators
that inhibit the flow of calcium into heart and blood vessel
tissues, which reduces tension in the heart, relaxes blood
vessels and lowers blood pressure. Unfortunately, most studies
have not shown that these agents reduce the risk of death
from hypertension, and some of these medications may increase
the risk of death from hypertension.
While some newer medications have shown to lower both
blood pressure and the risks of heart disease, they had
not been tested against each other until recently. This
was addressed with the Antihypertensive and Lipid-Lowering
Treatment to Prevent Heart Attack Trial (ALLHAT). Begun
in 1994, involving over 42,000 individuals and the largest
such trial to date, this important study showed that “traditional”
diuretics were more effective in treating high blood pressure.
Participants with high blood pressure were randomly given
diuretics, calcium channel blockers, ACE inhibitors or alpha
blockers.
Results five years later revealed that, compared to the
other classes of drugs in the study, diuretics were not
only significantly more effective in lowering high blood
pressure, but also in lowering the risk of cardiovascular
events (e.g., stroke, angina, heart failure). In fact, the
alpha blocker category was terminated in March 2000 due
to a higher rate of cardiovascular events and hospitalization
compared to diuretics. Based on these findings, the ALLHAT
researchers concluded that drug therapy to lower blood pressure
should be initiated with diuretics.
The ALLHAT researchers did recognize some limitations to
the study. Commenting on the significantly lower blood pressure
attained with the diuretic-controlled group (compared to
calcium channel blockers and ACE inhibitors), the benefit
may have been secondary to overall better blood pressure
control in that group, and perhaps not just from the diuretic
itself. Indeed, other studies have shown a marked and significant
benefit from ACE inhibitors, specifically ramipril, in reducing
the progression of atherosclerosis, preventing strokes and
heart attacks, and prolonging life in patients with vascular
disease, hypertension, diabetes and congestive heart failure.
The majority of patients with hypertension will need to
take medications for the rest of their lives in order to
control the condition. However, research has suggested that
some patients with only slightly elevated blood pressures
may eventually be able to stop taking medications and control
their condition through lifestyle changes alone. The two most important
lifestyle changes tracked by the study were weight loss
and maintaining a low-salt diet. Strategies such as exercise,
diet plans and, especially, changes in drugs should not
be undertaken on one's own, but first discussed with one's
physician.
How does high blood pressure affect
lifestyle?
People with hypertension should avoid certain activities
and situations that may raise their heart rates and blood
pressure to dangerous levels.
These include the following:
It is very important for hypertensives to
limit the amount of time spent in these activities to less
than 10 minutes, after which they should sit down out of the
heat for a few minutes before standing to minimize the risk
of dizziness or passing out (syncope).
Hypertensives must also be careful about using certain
over-the-counter (OTC) medications that contain vasoconstrictors,
which can elevate blood pressure.
Such medications include:
Hypertensives are also encouraged to follow
all of their physician’s orders regarding treatment,
in order to prevent serious health consequences. However,
patients are encouraged to discuss with their physicians any
side effects or other concerns that they may have about their
treatment.
High blood pressure in women
Once thought of as a “male disease,” high
blood pressure affects an equal number of women and men.
As with men, hypertension
in women is generally without symptoms, and, while treatable,
generally has no cure. All women are encouraged to learn
about their risks for hypertension and what can be done
to prevent it.
Below are some facts about women and hypertension:
