An exercise tolerance test (ETT) – also known as an exercise electrocardiogram (ECG) – helps to diagnose ischaemic heart disease, which is the common cause of angina and other heart problems. It can also help to assess the severity of ischaemic heart disease.

What is an exercise tolerance test?

An exercise tolerance test (ETT) records the electrical activity of your heart whilst you exercise.

How is an exercise tolerance test done?

Small electrodes are placed on to your chest. Wires from the electrodes are connected to the ECG machine. You will then be asked to exercise on a treadmill or on an exercise bike. The exercise starts at a very easy pace, and is gradually made more strenuous by increasing the speed and incline of the treadmill, or by putting some resistance on the bike wheel. During exercise ECG tracings are performed looking for abnormalities in the electrical activity of the heart

Why is an exercise tolerance test done?

The ETT is a test to diagnose and assess the severity of coronary artery disease and narrowings of the coronary arteries. It is routinely used in the investigation of patients with chest pains and breathlessness. The test is also used in screening patients for sudden cardiac death and in the assessment of patients for certain insurances, and licenses including DVLA and EASA.

Most people manage to do the ETT. It can be hard work, but the level of exercise chosen aims to match your normal capabilities. At any stage you can tell the person doing the test if you feel it is too difficult, and the test will be stopped. The test will also be stopped if you develop unpleasant pains or if you become very tired, or very short of breath.

Are there any risks when doing an exercise tolerance test?

An ETT is done without any problems in the vast majority of cases. If you do not have coronary artery disease then complications are rare. However, serious complications of heart attack or arrhythmia occur in a very small number of people who have coronary artery disease. Dr Jagathesan personally supervises all his private exercise stress tests to ensure patient safety at all times.