An exercise tolerance test measures your heart's rhythm and electrical activity and your blood pressure during exercise, and takes place on a treadmill within the clinic. During the test, ten electrodes are attached to your chest for the 12 lead ECG and an inflatable cuff is placed around your upper arm to monitor your blood pressure.
The test commences by taking resting measurements for the blood pressure and ECG. Then, you will stand on the treadmill which when you are ready, will start moving and every 3 minutes the speed and slope will be increased. The standard protocol is the Bruce protocol, with the modified Bruce protocol used if a reduced level of effort is required.
The time on the moving treadmill will continue until certain criteria are achieved. Such criteria may be attaining an age related predicted maximum heart rate, you experience your symptoms with some associated ECG changes, your symptoms are uncomfortable and you would prefer to stop, the ECG develops changes, your blood pressure or heart rate do not follow expected patterns or you become tired and can not continue. You are ultimately in charge, and if you wish to stop the test, it will be stopped.
The test usually lasts 30 minutes and afterwards you are able to continue a normal day; however if you are not used to exercise, you may feel fatigued. Results are usually available instantly and your consultant may wish to discuss them immediately with you, rather than requiring you to attend a separate appointment.
It may be necessary to stop some medications prior to an exercise test; if this is the case, your consultant will advise this.
An exercise tolerance test is often used as part of a screening medical for certain jobs with safety critical responsibilities such as public service drivers, ie taxi, bus and train drivers, particularly after a heart attack or chest pain. Pilots and some categories of motor racing licenses may also require this test.