Skip to main content
Cardiothoracic Services

This site is best viewed with a modern browser. You appear to be using an old version of Internet Explorer.

Cardiopulmonary Exercise testing (CPET)

Cardiopulmonary Exercise Testing (CPET) lets your doctor assess how your lungs, heart and muscles work when you exercise.

During the test, we will ask you to cycle on a stationary exercise bike (or, in some cases, walk on a treadmill). We will measure how much air you breathe, how much oxygen you need and how fast your heart is beating when you exercise.

Preparing for your CPET

Wear comfortable, loose-fitting clothing and flat shoes that will not slip off, such as trainers.


Before the test, you can take breathing medications, such as inhalers, and any other medications that you normally take. Continue your normal medication regime, unless otherwise stated by your doctor.

Smoking, eating and drinking

If you smoke, please avoid smoking for at least eight hours before the test.

Do not eat, or drink coffee, tea or any other drinks containing caffeine for at least three hours before the test.

This is to make sure that the measurements we take are as accurate as possible.

Your health

Please tell us about any conditions (temporary or permanent) that could affect your ability to move, walk, stand, or keep your balance while on the exercise bike (or treadmill).

If you are unable to cycle or walk, the best time to discuss this is when you are first told about the test. Please contact the doctor who referred you for the test as soon as possible to let them know.

Your CPET appointment

Arrive 10 minutes before the test. If you are more than 10 minutes late, we may have to cancel the test. This is because each test takes between 45 minutes and one hour and will delay other patients for the rest of the day.

Make sure you are well rested and avoid any heavy exercise on the day. You may need to reschedule the test if you feel unwell (for example, if you have a cold or chest infection).

The test is a maximum effort exercise test, so we want you to continue for as long you possibly can. It is normal to be cycling (or walking) for between eight and 12 minutes.

Initially the effort required is low and it gradually increases throughout the test. The last one to two minutes of the test will involve more intense effort.

The test

Before the test begins, the cardiac physiologist(s) will explain it to you. You can ask them any questions or share any concerns you may have.

To track your heart during exercise, we will put sticky patches called electrodes on your chest. We will clean your chest with alcohol and shave in some areas (if necessary) before we put the electrodes on.

We will attach an inflatable cuff on your upper arm to measure your blood pressure, put a plastic probe over your fingertip to measure the amount of oxygen in your blood, and put on a facemask to check your lungs. These will not hurt.

We will ask you about the symptoms you have had while exercising in the past.

Try to describe any:

  • chest discomfort
  • breathing problems
  • lightheadedness
  • dizziness
  • fluttering in the chest
  • weakness
  • tiredness or anything else you think may be relevant.

Usually, one to two Cardiac Physiologists will carry out the test: sometimes a doctor may supervise

During the test we will check:

  • your heart rate and rhythm
  • blood pressure
  • breathing rate
  • the amount of oxygen you use
  • how much oxygen is in your blood (finger probe)
  • how much work you are doing.

In some cases, we will perform an echocardiogram (echo) at rest and immediately following peak exertion.

We will first take your resting measurement, which will be for two minutes, while you sit still on the exercise bike. You then start to turn the pedals with no resistance for another two minutes.

After this, the resistance on the pedals increases gently and gradually until you are unable to keep turning the pedals at at least 60 rotations per minute.

Keep cycling until we ask you to stop, or until you are unable to carry on.

During the recovery stage, keep cycling gently. There will be no resistance in the pedals.

In the recovery period, we will continue checking your breathing, heart rate, blood pressure and oxygen level.

After the test

You can eat and drink as usual.

Depending on how you feel you may go about your normal routine or take it easy if you feel tired.

Do not take a hot shower for at least an hour after the test. Your blood vessels expand with exercise and need time to return to normal. A hot shower may expand them more causing low blood pressure and dizziness.

If you have any questions about the test, please ask.


We will look at the data and produce a report. The CPET doctor will review the report and interpret the findings, before passing the report and interpretation to the doctor who referred you for the test.

Find us and contact us

Please see Electrocardiogram (ECG) - Find us and contact us