Exercise stress testing
What is exercise stress testing?
Exercise stress testing is a procedure used by doctors to measure the performance and capacity of the heart, lungs and blood vessels during exercise. The testing is sometimes referred to as a 'clinical exercise stress test', a 'cardiac stress test', or simply a 'stress test'.
A common type of exercise stress test involves using an electrocardiogram (ECG) to record electrical signals from your heart during exercise. Alternatively, an echocardiogram may be used instead of an ECG. An echocardiogram uses sound waves (ultrasound) to produce images of your heart. A third type of exercise stress test involves injecting a radioactive material and following its progress through the heart’s blood vessels. This is often called a 'nuclear stress test' or a 'myocardial stress test'.
In some people, exercise stress testing is not suitable. In such cases, medicines may need to be used instead of exercise to stimulate the heart. This is called 'pharmacological stress testing'.
Why is exercise stress testing done?
Exercise stress testing is commonly used by doctors to help them make a diagnosis in people with suspected heart disease.
Exercise stress testing may also be carried out in people known to have heart disease to help identify those people at highest risk, to assess the progress of their heart disease, to assess the effect that a particular treatment (e.g. angioplasty) is having, or to assess the person’s capacity to undertake physical activity safely.
What do I need to do to prepare for the test?
Any type of exercise stress test will involve you doing some exercise. Therefore, you need to wear comfortable clothing and shoes suitable for walking or cycling. For women, it is best to wear a shirt with non-metallic buttons.
ECG exercise stress testing
If you are having an ECG exercise stress test, no special preparations are usually necessary. However, it is best to avoid drinking cold water or exercising straight before your test.
Echocardiogram exercise stress testing
If you are having an echocardiogram exercise stress test, your doctor may ask you not to eat for a few hours leading up the test.
Nuclear stress testing
If you are having a nuclear stress test done, you will be provided with a number of specific instructions to follow leading up to the test. You will be advised not to drink or eat any liquids or foods that contain caffeine for 24 hours before the test. This includes any type of coffee (including decaffeinated), any type of tea (including herbal teas), cola drinks, chocolate drinks, bars or biscuits. The centre where you are having the test done may also require you to fast for a number of hours before your test.
A number of heart and blood pressure medicines can interfere with the testing. You will need to check with your doctor whether you should stop taking certain medicines and, if so, when.
If you have diabetes, you need to inform the centre where you are having the testing done at the time that you book your test. If you are pregnant (or may be) or you are breastfeeding you should also let the centre know, as the test is not usually performed on women in these conditions.
What happens during the test?
What you can expect to happen during testing will depend on the type of test you are having done.
ECG exercise stress testing
If you are having an ECG exercise stress test, you will have several electrodes attached to your arms, legs and chest. You will then be asked to walk on a treadmill. The speed and gradient (steepness) of the treadmill will be increased every few minutes. The test will be stopped if you develop symptoms such as severe fatigue, breathlessness, tired legs or chest pain. If at any time during the test you feel unwell, you need to tell the doctor immediately.
Throughout the test, and for some time after the test finishes, a doctor will monitor your pulse and blood pressure as well as the electrocardiogram. If the doctor is concerned about any changes observed during the test, it will be stopped early.
Echocardiogram exercise stress testing
If you are having an echocardiogram stress test, the exercise part of the test will be the same as in an ECG stress test. Before and immediately after exercise, you will be asked to lie on a table. A cool gel will be spread on your chest and a device called a transducer will be pressed against your skin to produce ultrasound images of your heart.
Nuclear stress testing
If you are having a nuclear stress test, a small amount of a radioactive chemical will be given as an injection into a vein in your arm (thallium or technetium). The injected chemical is called a ‘tracer’. As the tracer moves through the blood vessels of your heart, a special camera or scanner will be used to take images.
The test will take place in 2 stages: at rest and during exercise. While you are being tested, you will be connected to an ECG machine and a blood pressure monitor. The exercise stage of the test will involve either walking on a treadmill, or riding an exercise bicycle. The difficulty of the exercise will be increased every few minutes. It is important that you tell the doctor immediately if you feel unwell at any time during the test, particularly if you have shortness of breath or chest pain.
In total, this test should take anywhere between 3 and 5 hours, including a break between the rest and the exercise stages. However, it is best to plan to be available all day.
Are there any risks or side effects?
Every effort will be made to minimise the risk of something going wrong. However, exercise stress testing does carry a small risk of complications. Emergency equipment and trained personnel will be available to deal with any complications that may arise.
Complications of exercise stress testing may include:
- severe hypotension (drop in blood pressure);
- a major disturbance of heart rhythm, requiring resuscitation;
- heart failure or prolonged heart pain;
- heart attack; and
- death (approximately 1 in 10,000 chance — this may be higher in patients with known severe heart disease).
If you are having an ECG or echocardiogram exercise stress test, there is a small chance that removal of the electrodes from your skin may cause irritation, redness or swelling.
Your doctor will have taken all these risks into account when recommending the testing for you. However, you should feel free to discuss these issues before agreeing to the testing.
After the test
A full report of the test will be sent to your regular doctor, usually the day after the test. The test will have shown if any part of your heart is not receiving enough blood because of blockages in the vessels that supply the heart or other irregularities in heart structure or function.
If the test results are normal, no further testing may be needed. However, if the results indicate a problem and your doctor suspects heart disease, you may be required to repeat the same test, or undergo further testing with other diagnostic procedures. In some cases, you may be referred to a heart specialist (cardiologist).
Further information and support
Talk to your doctor if you have any questions or concerns about the testing. You may also like to contact the hospital or centre where you will be having the test done.
Last Reviewed: 20/04/2011
1. Heart Foundation. Coronary heart disease diagnosis (last modified 19 Aug 2009). (http://www.heartfoundation.org.au/Heart_Information/Heart_Conditions/Coronary_Heart_Disease/Coronary_Heart_Disease_Diagnosis/Pages/default.aspx (accessed Apr 2011).
2. MayoClinic.com. Exercise stress test (15 Dec 2009). http://www.mayoclinic.com/health/stress-test/MY00977 (accessed Apr 2011).
3. MayoClinic.com. Echocardiogram (16 Jul 2010). http://www.mayoclinic.com/health/echocardiogram/MY00095 (accessed Apr 2011).
4. MayoClinic.com. Nuclear stress test (15 Dec 2009). http://www.mayoclinic.com/health/nuclear-stress-test/MY00994 (accessed Apr 2011).
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