An exercise tolerance test (also called an exercise stress test or exercise ECG) measures how the heart responds to physical exertion. It’s usually performed on a treadmill, though a stationary bike can be used if needed. Speed and incline increase at 3-minute intervals, while heart rate and blood pressure are continuously monitored.

An ETT helps assess exercise capacity and identify conditions such as coronary artery disease and arrhythmias in patients experiencing chest pain, breathlessness, dizziness or palpitations. An ECG is recorded at rest, during exercise, and in recovery.

A typical ETT takes around 15 minutes, depending on the patient’s fitness and heart rate response. The test can be stopped at any point if needed, and can also be combined with echocardiography as part of a stress echo procedure.