The resting ECG looks at the electrical activity of the heart when the patient is lying comfortably and therefore doesn’t test the heart under load.
The exercise test allows the cardiologist to see how the heart performs under load. Although the exercise test has some limitations it can be useful in screening, assessing exercise capacity, in the investigation of patients with chest pain and for some other indications such as heart rhythm problems.
Exercise is usually on either a treadmill or exercise bike and performed with ECG electrodes connected. The blood pressure is measured frequently during the test. All test results should be treated with caution and interpreted in the context of a clinical assessment.