What is a stress test?

Date: Aug-31-2013A stress test, also known as an exercise test or treadmill test, is used by doctors to determine how well a patient's heart works during physical activity. When the heart pumps harder during exercise, the stress test can reveal problems, such as poor blood supply through the coronary arteries - these problems might not be apparent at other times.

The stress test is also useful when the doctor is advising patients on the best type of physical activity for them.

A stress test typically involves walking on a treadmill or riding a stationary bicycle while the patient's breathing, blood pressure and heart rhythm are monitored.

According to the American Heart Association, "The (stress) test
can show if there's a lack of blood supply through the arteries that go to the heart (coronary arteries)".

Some patients may not be able to do the exercise involved in a normal stress test, examples may include people with arthritis or certain disabilities in their limbs. There is another test - the pharmacological (chemical) stress test - in which the doctor gives the patient a medicine to make the heart work harder, as it might during exercise.
Why do a stress test

The doctor may recommend a stress test to determine whether the patient:

has arrhythmia - irregular heartbeat or abnormal heart rhythm. When the electrical impulses that coordinate heart rhythm are faulty, the heart may beat irregularly.

has symptoms that are heart-related, such as difficulty breathing or chest pain
is suitable for an exercise program, and if so, how hard he/she should exercise
is suitable for a cardiac rehabilitation program, and if so, how hard he/she should exercise
is responding to heart treatment
needs other tests to detect narrowed arteries, such as a coronary angiogram

A study carried out at the Cleveland Clinic found that a stress test can identify obstructive sleep apnea patients most at risk of death.
What happens during a treadmill stress test?

During a stress test the doctor aims to determine the patient's heart rate, blood pressure, breathing, and how tired he/she feels under different levels of physical activity.

During a stress test, the patient also undergoes an electrocardiogram (ECG or EKG) test. This is a simple test that records the heart's electrical activity - it helps the doctor understand how well the heart is working. An ECG shows how fast the heart is beating, it analyzes heart rhythm, and measures the strength and timing of electrical signals as they pass through each part of the heart.

For the ECG test, wires with electrodes are hooked up to the patient's chest, arms, shoulders and legs. Toward the end the patient may have to breathe into a mouthpiece.

The stress test helps determine whether the patient has heart disease, and if so, how severe it is.

Below is a step-by-step description of what happens during a stress test using a treadmill:

You are hooked up to the device that monitors your heart
A blood pressure cuff is wrapped around the upper part of one arm
You stand on the treadmill
The treadmill starts to move and you walk slowly
The treadmill speed will gradually increase
The treadmill may go into an uphill (incline) position
The treadmill has a railing you can hold on to in case you have a problem with balance. However, try not to hold onto it all the time (unless you are told to), as this may affect the reliability of the readings
You are asked to breathe into a tube for a minute or two
After slowing down, you get off, stand still for a few seconds and then lie down
The medical team takes further readings of your blood pressure, etc.

How long does a stress test last?

Stress tests do not last more than 15 minutes. The doctor needs to work the heart harder than normal for between eight to 12 or so minutes.

If the following signs or symptoms emerge, the doctor will stop the test:

You feel dizzy
You start panting severely
Your blood pressure is too high (or low)
Arrhythmia is detected
You have chest pain
The ECG device detects certain abnormal changes

The results of the stress test

If the stress test detects no abnormality, the doctor will recommend no additional tests.

Some people, however, may appear "healthy" after a stress test, but continue having symptoms that brought them to the doctor in the first place. These symptoms may even get worse. In such cases the doctor may recommend a nuclear test, which will probably give a more detailed and accurate assessment of the state of the patient's heart.

If the stress test detects an arrhythmia or coronary artery disease, the doctor and patient will discuss a treatment plan, and possibly further tests.

According to the National Lung and Heart Institute, patients who cannot exercise for as long as what is considered normal for their age may have problems of blood flow to the heart, anemia, lung disease, or may be extremely unfit.

The stress test may have been ordered to guide treatment for an existing heart condition. If so, the results will help the doctor determine whether the current treatment is appropriate.
Video - What is a stress test?

This video explains what a stress test is, what it is for, and what happens during the test.

Written by Christian Nordqvist

Copyright: Medical News Today

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