Stress testing provides information about how your heart works during physical stress. Some heart
problems are easier to diagnose when your heart is working hard and beating fast.
testing, you exercise (walk or run on a treadmill or pedal a stationary bike) to make your heart
work hard and beat fast. Tests are done on your heart while you exercise.
You might have arthritis or another medical problem that prevents you from exercising during a
stress test. If so, your doctor may give you medicine to make your heart work hard, as it would during
exercise. This is called a pharmacological (FAR-ma-ko-LOJ-ih-kal) stress test.
Doctors usually use stress testing to help diagnose
disease (CHD). They also use stress testing to find out the severity of CHD.
CHD is a disease in which a waxy substance called plaque (plak) builds up in the coronary arteries.
These arteries supply oxygen-rich blood to your heart.
Plaque narrows the arteries and reduces blood flow to your heart muscle. The buildup of plaque
also makes it more likely that blood clots will form in your arteries. Blood clots can mostly or
completely block blood flow through an artery. This can lead to chest pain called
(an-JI-nuh or AN-juh-nuh) or a
You may not have any signs or symptoms of CHD when your heart is at rest. But when your heart
has to work harder during exercise, it needs more blood and oxygen. Narrow arteries can't supply
enough blood for your heart to work well. As a result, signs and symptoms of CHD may occur only during
A stress test can detect the following problems, which may suggest that your heart isn't getting
enough blood during exercise:
- Abnormal changes in your heart rate or blood pressure
- Symptoms such as shortness of breath or chest pain, especially if they occur at low levels
- Abnormal changes in your heart's rhythm or electrical activity
During a stress test, if you can't exercise for as long as what is considered normal for someone
your age, it may be a sign that not enough blood is flowing to your heart. However, other factors
besides CHD can prevent you from exercising long enough (for example, lung disease,
or poor general fitness).
Doctors also may use stress testing to assess other problems, such as
heart valve disease
or heart failure.
Standard Exercise Stress Test
A standard exercise stress test uses an
to detect and record the heart's electrical activity.
An EKG shows how fast your heart is beating and the heart's rhythm (steady or irregular). It also
records the strength and timing of electrical signals as they pass through your heart.
During a standard stress test, your blood pressure will be checked. You also may be asked to breathe
into a special tube during the test. This allows your doctor to see how well you're breathing and
measure the gases that you breathe out.
A standard stress test shows changes in your heart's electrical activity. It also can show whether
your heart is getting enough blood during exercise.
Imaging Stress Test
As part of some stress tests, pictures are taken of your heart while you exercise and while
youíre at rest. These imaging stress tests can show how well blood is flowing in your heart and how
well your heart pumps blood when it beats.
- One type of imaging stress test involves
(echo). This test uses sound waves to create a moving picture of your heart. An exercise stress echo
can show how well your heart's chambers and valves are working when your heart is under stress.
A stress echo also can show areas of poor blood flow to your heart, dead heart muscle tissue,
and areas of the heart muscle wall that aren't contracting well. These areas may have been damaged
attack, or they may not be getting enough blood.
- Other imaging stress tests use radioactive dye to create pictures of blood flow to your heart.
The dye is injected into your bloodstream before the pictures are taken. The pictures show how much
of the dye has reached various parts of your heart during exercise and while you're at rest.
Tests that use radioactive dye include a thallium or sestamibi stress test and a positron
emission tomography (PET) stress test. The amount of radiation in the dye is considered safe for
you and those around you. However, if you're pregnant, you shouldn't have this test because of risks
it might pose to your unborn child.
Imaging stress tests tend to detect CHD better than standard (nonimaging) stress tests. Imaging
stress tests also can predict the risk of a future heart attack or premature death.
An imaging stress test might be done first (as opposed to a standard exercise stress test) if
- Can't exercise for enough time to get your heart working at its hardest. (Medical problems,
such as arthritis or leg arteries clogged by plaque, might prevent you from exercising long enough.)
- Have abnormal heartbeats or other problems that prevent a standard exercise stress test
from giving correct results.
- Had a heart procedure in the past, such as
bypass grafting or
coronary intervention, also known as coronary angioplasty, and
Who Needs Stress Testing?
You may need stress testing if you've had chest pains, shortness of breath, or other symptoms
of limited blood flow to your heart.
Imaging stress tests, especially, can show whether you have
disease (CHD) or a heart valve problem. (Heart valves are like doors; they open and shut to let
blood flow between the heart's chambers and into the heart's arteries. So, like CHD, faulty heart
valves can limit the amount of blood reaching your heart.)
If you've been diagnosed with CHD or recently had a
attack, a stress test can show whether you can handle an exercise program. If you've had
coronary intervention, also known as coronary angioplasty, (with or without
or coronary artery
bypass grafting, a stress test can show how well the treatment relieves your CHD symptoms.
You also may need a stress test if, during exercise, you feel faint, have a rapid heartbeat or
a fluttering feeling in your chest, or have other symptoms of an
(an irregular heartbeat).
If you don't have chest pain when you exercise but still get short of breath, your doctor may
recommend a stress test. The test can help show whether a heart problem, rather than a lung problem
or being out of shape, is causing your breathing problems.
For such testing, you breathe into a special tube. This allows a technician to measure the gases
you breathe out. Breathing into the tube during stress testing also is done before a
to help assess whether you're a candidate for the surgery.
Stress testing shouldnít be used as a routine screening test for CHD. Usually, you have to have
symptoms of CHD before a doctor will recommend stress testing.
However, your doctor may want to use a stress test to screen for CHD if you have diabetes. This
disease increases your risk of CHD. Currently, though, no evidence shows that having a stress test
will improve your outcome if you have diabetes.
... ... ...
Your doctor uses the test to:
- Help to assess symptoms, such as chest pain, shortness of breath or palpitations, to determine
whether they are coming from the heart
- See if enough
to your heart as you get more active
- Learn how your heart
medications are working
- Find out if it's likely that you have
coronary heart disease
and need more testing
- Identify abnormal
- See how well your heart valves are working
- Help you develop a safe
What Happens During the Exercise Stress Test?
First, a technician will gently clean 10 small areas on your chest and place small, flat, sticky
patches called electrodes on them. They'll be attached to an electrocardiogram monitor -- called
an EKG -- that charts your heart's electrical activity during the test.
Before you start
exercising, the technician will perform an EKG to measure your
at rest. He'll also take your
You will begin to exercise by walking on a treadmill or pedaling a stationary bicycle. The
incline or resistance will gradually increase. You will be asked to exercise until you feel exhausted.
If medication is used, or it is a nuclear stress test, an IV will be inserted in your arm in order
to have the medication administered.
At regular intervals, the lab personnel will ask how you are feeling. Tell them if you feel:
- Chest or arm discomfort
- Short of breath
- Any other unusual symptoms
It's normal for your heart rate, blood pressure, breathing rate, and perspiration to increase
during the test. The lab personnel will watch for anything on the EKG monitor that suggests the
test should be stopped.
After the test, you'll walk or pedal slowly for a couple of minutes to cool down. Your heart
rate, blood pressure, and EKG will continue to be monitored until the levels begin returning to
Although the appointment lasts about 60 minutes, the exercise time is usually between 7
and 12 minutes.