You probably remember the routine from your last physical
exam: A nurse wraps a cuff around your upper arm, pumps the
cuff full of air, and then lets the air out slowly while listening
through a stethoscope. Most likely, you don't remember feeling
anything - except perhaps that odd sensation of the blood pounding
in your arm! For most guys and girls, this is the only time they
think about their blood pressure.
Understanding Blood Pressure
Every person needs blood pressure to live. Without it, blood
wouldn't be able to circulate through the body to carry oxygen
and fuel vital organs.
Blood pressure is the pressure your blood exerts against your
blood vessel walls as your heart pumps. Blood pressure rises with
each heartbeat and falls when the heart relaxes between beats, but
there is always a certain amount of pressure in the arteries. That
blood pressure comes from two physical forces. The heart creates
one force as it pumps blood into the arteries and through the
circulatory system. The other force comes from the arteries
resisting the blood flow.
Blood pressure changes from minute to minute and is affected not
only by activity and rest, but also by temperature, diet, emotional
state, posture, and medications.
Blood pressure is measured in millimeters of mercury (written as
mm Hg). For example, normal blood pressure in adults should be less
than 120/80 mm Hg. The higher, or top, number - in this example
it's 120 - is called
systolic
pressure and represents the pressure at the peak of each heartbeat.
The lower, or bottom, number (80 in this example) is called
diastolic
and represents the pressure when the heart is resting between
beats. The systolic pressure is stated first and the diastolic
pressure comes second. For example: 120/80 (120 over 80) means that
the systolic pressure is 120 and the diastolic pressure is 80.
Blood pressure is measured using an instrument called a
sphygmomanometer
(pronounced: sfig-mow-mah-
nah-
meh-ter). A cuff is wrapped around a person's upper arm and
pumped up to create pressure. When the cuff is inflated, it
compresses (squeezes on) a large artery in the arm, stopping the
blood flow for a moment. Blood pressure is measured as air is
gradually let out of the cuff, which allows blood to begin to flow
through the artery again when the blood pressure in the artery is
greater than the pressure in the cuff.
Listening with a stethoscope - the instrument used to hear
things like the heart beating inside the body - over the artery
allows a doctor or nurse to hear the first pulse as the blood flows
through. This is the systolic pressure. The diastolic pressure is
noted when the sounds disappear.
What Is Hypertension?
Hypertension is the medical term for high blood pressure. Most
people associate high blood pressure with getting older, so it may
seem odd that teens can have the condition. Although high blood
pressure is rare in young people (only about 1% to 3% of kids in
the United States have hypertension), it's important to check
for it. Even babies can have high blood pressure!
Almost 60 million Americans age 6 and older have high blood
pressure. That means about 1 in 5 Americans has the condition.
Because a third to a half of the people who have high blood
pressure don't even know it, doctors are careful to check their
patients for hypertension regularly.
Blood pressure of less than 120 over 80 is considered a normal
reading for people 18 and over. A borderline high systolic pressure
of 120 to 139 or a diastolic pressure of 80 to 89 needs to be
closely monitored. A blood pressure reading equal to or greater
than 140 over 90 is considered high in people over the age of
18.
Because of the way blood pressure readings are calculated for
children and teens, readings that doctors consider high in teens
can be lower than the blood pressure readings that are considered
high in adults.
In teens up to age 18, high blood pressure is defined as a blood
pressure greater than the 95th percentile for their age, height,
and gender (in other words, 95% of kids at the same age, height,
and gender will have blood pressure below this number).
Measurements between 90% to 95% of the expected range are
considered high - normal or prehypertension.
Teens with blood pressure readings that are greater than 90% of
the expected range are three times more likely than those with
average readings to develop high blood pressure as adults.
A doctor will average at least three blood pressure measurements
taken at different times before determining that a teen has
hypertension. Most teens will have their blood pressure checked
during an annual physical exam. Doctors recommend that older teens
with normal blood pressure get their blood pressure checked
yearly.
If your blood pressure is near the top of the normal range or if
you have a family history of high blood pressure, you're at a
higher risk for developing hypertension. Your doctor can advise you
as to how often you should have your blood pressure checked in this
situation.
What Causes Hypertension?
Most blood pressure doesn't have a cause and is called
essential
or
primary
hypertension
. In cases where the cause of high blood pressure is known (called
secondary hypertension
), it is usually the result of kidney problems, hormonal disorders,
abnormalities of the aorta (the main artery that carries oxygenated
blood to the body), or a narrowing of certain smaller arteries.
Doctors screen teens with high blood pressure for secondary causes
with physical examination and laboratory testing.
Some teens may inherit the tendency toward higher blood pressure
from one or both parents. Although hypertension often runs in
families, some people with a strong family history of high blood
pressure may never develop it.
Kids and teens who are obese are at a higher risk for
hypertension. Lack of exercise makes it easier to become overweight
and increases the chance of high blood pressure. People who drink a
lot of alcohol or take illegal drugs like amphetamines and
cocaine are also at risk of developing the condition. In some
cases, medications like steroids or birth control pills can cause
high blood pressure.
Pregnant women also may be diagnosed with hypertension. This
type of hypertension is known as preeclampsia (pronounced: pree-ih-
klamp-
see-uh), or toxemia. It's uncommon, though: Only about 6% to 8%
of pregnant women get this condition.
How Does High Blood Pressure Affect the Body?
High blood pressure adds to the workload of the heart and
arteries. The heart must pump harder and the arteries must carry
blood that's moving under greater pressure. If high blood
pressure continues for a long time, the heart and arteries may no
longer work as well as they should. Other body organs, including
the kidneys, eyes, and brain also may be affected.
People can live with hypertension for many years without having
any symptoms. That's why high blood pressure is often called
"the silent killer." Though a person may not have any
symptoms, it doesn't mean that the high blood pressure
isn't affecting the body.
Having high blood pressure puts a person at more risk for
strokes, heart attacks, kidney failure, loss of vision, and
atherosclerosis (hardening of the arteries). In rare cases, severe
hypertension can sometimes cause headaches, visual changes,
dizziness, nosebleeds, and nausea.
A person who has high blood pressure and experiences any of
these symptoms should be treated immediately.
How Do Doctors Diagnose High Blood Pressure?
For most teens, the only way to know if you have high blood
pressure is to get your blood pressure checked. It's painless
and fast.
A single reading showing high blood pressure doesn't
necessarily mean that you have hypertension, but it is an
indication that it should be watched carefully. Some people have
what's called "white coat hypertension," meaning that
their blood pressure rises at a doctor's office because they
are anxious. When they feel more relaxed, their blood pressure
usually decreases. Ambulatory blood pressure monitoring, a test
where your blood pressure is measured over a whole day, helps in
separating white coat hypertension from true hypertension.
Someone may need to get his or her blood pressure checked
several times over a period of days or weeks to determine if they
have hypertension. A doctor should recommend how to go about
this.
Doctors usually ask for the following information to help
determine what might cause someone's high blood pressure:
- a complete medical history, including questions about a
person's present and past health and the health of family
members
- whether that person is taking any medications
- whether that person smokes or drinks alcohol
- eating and exercise habits
The doctor will probably take weight and height measurements,
and might perform urine or blood tests to check for other physical
problems, such as a kidney problem or a
thyroid disorder
that sometimes can be the underlying cause of high blood pressure.
A doctor may also test for high blood
cholesterol
and other conditions that can increase someone's risk for
developing heart disease or stroke.
How Is Hypertension Treated?
Hypertension can be a temporary or lifelong disease, depending
on the cause. Regardless of what causes high blood pressure, the
important thing is to keep it under control. People who manage
their high blood pressure with a treatment program lower their risk
of having serious complications as they get older.
Although medication may be necessary to control high blood
pressure, in many cases it can be managed with lifestyle
improvements, such as weight loss and dietary changes.
If you've been diagnosed with hypertension, you and your
doctor will work as a team to decide on the best course of action
for you. Your doctor will most likely recommend that you make
lifestyle changes such as eating less fat and salt, avoiding
alcohol and cigarettes, and making sure you get plenty of
exercise.
Exercise is an important treatment for hypertension. Only people
with severe uncontrolled hypertension, which is very
rare, need to be careful about exercise. The American Academy
of Pediatrics (AAP) recommends that teens with severe hypertension
avoid certain sports only until their hypertension is under
control. Sports on the "avoid" list include weight
lifting and bodybuilding, especially if done competitively - in
other words, sports that focus on building muscle mass but do not
balance it with aerobic activity. People whose hypertension is less
severe or under control are encouraged to participate in sports as
a way of managing their condition.
Can I Prevent Hypertension?
Here are some suggestions that can lessen your chances of
developing high blood pressure and help keep you healthy in many
other ways:
- Maintain a normal
weight for your height
.
- Exercise regularly. This can help prevent you from becoming
overweight or help you in losing pounds if you need to. Exercise
also helps keep your heart and blood vessels strong and
healthy.
- Eat a healthy diet that includes mostly whole grains, low-fat
dairy products, fruits, and vegetables.
- Don't smoke. Smoking and high blood pressure are major
risk factors for having a heart attack or stroke later in
life.
- Keep your stress levels in check. It may help to practice
relaxation techniques such as deep breathing exercises.
- Decrease your sodium (salt) intake. Consuming less sodium has
been proven to help lower blood pressure in some people and may
prevent some from developing high blood pressure in the first
place. Salt is often found in breads, baked goods, and other
processed/canned foods.
- Avoid drinking too much alcohol, which is associated with
high blood pressure.
- Know your blood pressure. Have it checked regularly -
although high blood pressure is more common in adults, it can
occur at any age.
Reviewed by:
Samuel S. Gidding, MD
Date reviewed: August 2008
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
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