Treadmill Electrocardiogram (ECG) (Exercise Stress Test)
An exercise stress test is a special non-invasive diagnostic test used to assess the response of your heart to an increased workload and oxygen demand during physical stress. It measures the heart performance to detect if there are significant blockages of the arteries supplying the heart muscles (i.e. a condition called ischemic heart disease as a result of reduced blood supply to the heart muscles due to coronary artery disease).
The exercise stress test is done by recording a modified 12-lead electrocardiogram (ECG) of your heart during rest, walking and jogging on a treadmill machine which is programmed at varying speeds and elevations. This test is also able to check the heart rhythm and blood pressure response to exercise as well.
How does the exercise stress ECG works?
A normal resting ECG may not be sensitive enough (and therefore inadequate) to detect the lack of blood supply to the heart muscles due to blockages of the arteries supplying the muscles.
The stress ECG can unmask this as the requirement and demand for oxygen via the blood supply to the heart is increased due to the increased workload of the heart through physical stress.
During the exercise stress test, the doctor in attendance will constantly assess and monitor your vital signs (i.e. heart rate and rhythm, blood pressure) and general state of health and the heart’s response to exercise. Recordings are taken simultaneously at every 3 minutes intervals, with the speed and elevation of the treadmill being gradually increased in the course of the test until you either reach your target exercise heart rate or develop symptoms of breathlessness or chest pains or indicate you are unable to continue the test.
The higher the level of exercise, the greater the workload and oxygen demand is required by the heart muscles. This test will therefore allow the doctor to assess whether the blood supply to the heart is sufficient to meet with the different stages of the exercise intensity and also the amount of physical exercise you can undertake comfortably (i.e. exercise tolerance).
Ideally this should be done with a cardiologist in attendance and require a specialist to read and interpret the results.