What is an exercise stress test?
A stress test is a diagnostic procedure where a person is asked to perform increasingly more strenuous exercise on a treadmill or exercise bike while the heart is being monitored with an ECG. It is designed to assess how well the heart works under a physical strain and to detect any evidence of coronary artery blockages. During exercise, the heart beats faster and requires more blood to work. It is in this state that any restriction of blood flow to the heart due to coronary artery blockages may show up. A stress test is sometimes called an exercise test or a treadmill test.
Why might my doctor order an exercise stress test?
Thee are a number of different reasons that your doctor may choose to order a stress test for you. These include:
- evaluate the significance of symptoms you may have including chest discomfort shortness of breath or palpitations
- screening test to see if there is any sign of heart disease – usually done in patients who are well and without symptoms
- check on people’s progress after angioplasty or bypass surgery
- evaluate the effects of a heart valve problem
- measure people’s level of fitness
How do I prepare for a stress test?
It is preferred that you refrain from eating and drinking for 2 hours prior to the test. You may also need to temporarily stop some of your heart medications for 24-48 hours. Your doctor will advise you about this when the test is being booked. You should wear comfortable clothes and footwear that you can exercise in.
What happens during an exercise stress test?
At the start of the procedure a technician or nurse will prepare the skin on your chest and place a number of ECG electrodes on. You will be asked to lie down and an ECG and blood pressure reading will be taken. You will then be asked to get on to the treadmill or exercise bike and begin exercising. This will be done under the direct supervision of a doctor.
The intensity of the exercise will be made gradually more difficult – usually in 3-minute stages. For a treadmill, both the speed and the incline are increased gradually. With exercise bikes, the pedalling resistance is increased.
During the test, the doctor or nurse will observe you closely and check your blood pressure and ECG at regular intervals. The test is ended when the doctor feels that you have had enough, when your heart rate reaches a certain level or when symptoms develop.
You will then be monitored for another 3-5 minutes while you are recovering.
Are there any risks with a stress test?
Stress tests are very safe. However, on rare occasions people have had problems arise during or after exercise. These include chest pain, rapid heart rates due to rhythm disturbance, faintness and even collapse. Your doctor will be with you throughout the test, and safety equipment is always immediately available.