Exercise tolerance test (ETT)

An exercise tolerance test (ETT), or treadmill test, measures how your heart performs during and after exercise.

Image showing a patient walking on a treadmill during an exercise tolerance test, while a clinician monitors the heart’s electrical activity and vital signs using ECG leads and equipment in a clinic setting.

It helps diagnose different heart conditions such as coronary artery disease, or heart rhythm problems (arrhythmias).

Your doctor may order this test if:

  • you’re having symptoms such as chest pain, breathlessness or dizziness
  • they suspect you have narrowing or blockages of the coronary arteries (vessels that supply blood to the heart)
  • you have an unusual heart rate or rhythm.

Before your appointment

Wear shoes and clothes that are comfortable for walking on a treadmill.

What happens?

The test will be done in a clinic or a hospital.

You’ll be asked to remove clothing from above the waist, and you’ll be given a gown. Sticky pads (electrodes) will be placed on your chest to record the activity of your heart while you exercise. Your blood pressure will also be monitored.

You will walk on a treadmill for up to 15 minutes. The treadmill speed and slope will slowly increase, making it gradually harder. You’ll be monitored to make sure you’re safe.

The test may be stopped if you have any symptoms such as:

  • abnormal heart rate or rhythm
  • chest pain
  • high or low blood pressure
  • shortness of breath
  • dizziness
  • feeling unwell.

You’ll be monitored for a short while after you’ve stopped exercising.

The appointment can take up to an hour.

After the test

You won’t get the results on the day. They will be sent to the doctor who ordered the test.

Key things to remember

Key things to remember

Infographic explaining exercise tolerance test (ETT) preparation, with icons showing the appointment takes about 1 hour, wear comfortable clothes and walking shoes, and that you will walk on a treadmill while your heart rate, rhythm and blood pressure are