Cardiopulmonary exercise test (CPET)
A monitored exercise test on a bike or treadmill, while your breathing and heart are measured, to assess how well your heart, lungs and muscles work together — often before major surgery or to investigate breathlessness.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- CPET measures how your heart, lungs and muscles cope with exercise, using a bike or treadmill while your breathing and heart are monitored.
- It is often used to judge fitness before major surgery and to investigate unexplained breathlessness, rather than to diagnose one specific disease.
- It is generally a safe, closely supervised test, but because you exercise hard it carries a small risk of problems such as an abnormal heart rhythm, faintness or breathlessness.
- You exercise only as hard as you safely can, the test can be stopped at any time, and you should wear suitable clothing and follow advice on medicines beforehand.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Gives an objective, whole-body measure of fitness rather than relying on how fit you feel.
People with certain unstable heart conditions, such as a recent heart attack, unstable angina, uncontrolled arrhythmia or severe symptomatic aortic...
You exercise to your limit with continuous monitoring. Breathlessness, a pounding heart and tired legs are expected.
A proper cool-down and monitoring until your heart rate and breathing have settled.
You exercise to your limit with continuous monitoring. Breathlessness, a pounding heart and tired legs are...
You ease off and are monitored as your heart rate, blood pressure and breathing return towards normal.
You can usually go home and resume normal activities, though you may feel tired and your legs may ache.
A specialist reviews the measurements and a report is usually available within days, often discussed at a...
What is a cardiopulmonary exercise test (CPET)?
A cardiopulmonary exercise test, or CPET, measures how your heart, lungs and muscles work together when you exercise. You pedal a static bike or walk on a treadmill while the effort is gradually increased, wearing a mask that measures the oxygen you breathe in and the carbon dioxide you breathe out, with your heart traced on an ECG throughout.
From this, the team can work out values such as your peak oxygen uptake and your anaerobic threshold — the point at which your body starts to rely more on energy pathways that do not need oxygen. Together these give an objective picture of your overall fitness and how your heart and lungs respond to effort.
CPET is commonly used to assess fitness before major surgery, to investigate breathlessness when its cause is unclear, and to help manage heart or lung conditions. It is a test, not a treatment: it measures how your body copes with exercise, helps weigh up the risks of an operation, and can guide planning, but it does not by itself diagnose a single disease.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Options at a glance
These are the main approaches described in this guide. The right option depends on the diagnosis, your goals and what your clinician thinks is safe.
Cycle (bike) CPET
Done on a static exercise bike with the resistance gradually increased. The most common type, as it keeps the upper body steady for accurate measurements.
Treadmill CPET
Walking, then walking faster or uphill, on a treadmill. Sometimes preferred when walking is more relevant to the question being asked.
Pre-operative CPET
Used before major surgery to assess fitness and help weigh up the risks and the level of care you may need afterwards.
Diagnostic CPET
Used to investigate unexplained breathlessness or reduced exercise tolerance, and to tell apart heart, lung and fitness-related causes.
Preparing for your test
- Ask which medicines to take or pause beforehand — some heart and blood pressure medicines may be adjusted, but never stop medication without advice.
- Wear loose, comfortable clothing and suitable shoes or trainers for exercise.
- Avoid a heavy meal, caffeine, alcohol and smoking for a few hours before the test.
- Avoid strenuous exercise on the day of the test.
- Bring any inhalers you use and a list of all your medicines.
- Tell the team about chest pain, palpitations, blackouts, joint or mobility problems, or any recent illness.
- Allow about an hour for the appointment, and expect to feel tired afterwards.
What happens
The test is done in a supervised unit by trained staff, with a clinician available if needed. Sticky electrodes are placed on your chest for a continuous ECG, a blood pressure cuff is fitted, a clip or probe measures your oxygen levels, and you wear a close-fitting mask or mouthpiece that measures the air you breathe.
You then exercise on a bike or treadmill, starting gently, with the effort increased step by step. Throughout, the team watches your ECG, heart rate, blood pressure, oxygen levels and breathing. You are encouraged to keep going until you reach your limit, but the test can be stopped at any time, by you or the staff, if there is chest pain, marked breathlessness, dizziness, a worrying change on the monitors or other concerns.
The exercise part usually lasts about 8 to 12 minutes. Afterwards you cool down and are monitored for a short while as your heart rate and breathing settle. A specialist then reviews and interprets the measurements.
Is this test right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- People with certain unstable heart conditions, such as a recent heart attack, unstable angina, uncontrolled arrhythmia or severe symptomatic aortic stenosis.
- Those unable to exercise meaningfully on a bike or treadmill because of mobility, joint or balance problems.
- Anyone with an acute illness, uncontrolled high blood pressure or another condition that makes hard exercise unsafe on the day.
- It is the wrong test when the question can be answered by a simpler assessment, or when urgent treatment, not testing, is needed.
Delay or rearrange if…
- You have a recent chest infection, fever or other acute illness.
- You have new or unstable chest pain, palpitations or blackouts that need assessment first.
- Your blood pressure is very high or your heart condition is currently unstable.
- You have not received clear advice on which medicines to take or pause.
Alternatives to discuss
- A six-minute walk test or other simpler walking test where a less demanding measure is enough.
- A standard (ECG) exercise stress test without breathing-gas analysis.
- An echocardiogram or other heart imaging to assess heart function.
- Breathing tests such as spirometry and lung volumes to assess the lungs.
- Clinical assessment alone where exercise testing is not feasible or appropriate.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Gives an objective, whole-body measure of fitness rather than relying on how fit you feel.
- Helps assess the risk of major surgery and plan the right level of aftercare.
- Can help work out whether breathlessness is mainly from the heart, the lungs or fitness.
- Measures useful values such as peak oxygen uptake and anaerobic threshold.
- Closely monitored throughout, so problems can be picked up and the test stopped promptly.
- Can guide exercise advice and track changes over time.
Risks & complications
- Breathlessness, tiredness and aching legs from the exercise itself.
- Sweating, a flushed face and a pounding heartbeat during hard effort.
- Mild discomfort from the mask, mouthpiece or chest electrodes.
- Feeling faint, dizzy or sick, especially just after stopping.
- A temporary abnormal heart rhythm during or after exercise.
- Chest tightness or wheeze, particularly if you have a lung condition.
- A drop in oxygen levels with exertion in people with heart or lung disease.
- A serious heart rhythm problem, fainting (collapse) or, very rarely, a heart attack.
- A fall or injury related to the treadmill or bike.
- Very rarely, an event needing emergency treatment or hospital admission.
CPET asks you to exercise to your limit, so it is done with continuous ECG, blood pressure and oxygen monitoring and trained staff ready to act, and the test is stopped at the first sign of a problem. Serious events are rare but not impossible, which is why it is carried out in equipped units and why people with certain unstable heart conditions are not tested. Tell the team about any chest pain, palpitations, blackouts or recent illness, and stop and speak up during the test if you feel unwell.
Published figures to discuss
CPET is a maximal exercise test, so most discomfort (breathlessness, tiredness, aching legs) is expected, while serious events are rare. Reported safety data from specialist statements give an order of magnitude rather than a precise personal risk, and depend heavily on careful patient selection and continuous monitoring. The figures below are drawn from the ARTP 2021 statement and should be read as cautious estimates that vary with the population tested and the setting.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Death related to the test | Around 2–5 per 100,000 tests | Very rare; the test is stopped early and emergency support is on hand if problems arise. Reported in the ARTP 2021 statement. | CPET as a predictor of complications in major surgery (PMC)ncbi.nlm.nih.govPublished figure |
| Major cardiac event | Around 1.2 per 10,000 tests | Rare; continuous ECG and monitoring allow prompt recognition. Reported in the ARTP 2021 statement. | CPET as a predictor of complications in major surgery (PMC)ncbi.nlm.nih.govPublished figure |
| Complication needing hospital admission | Up to about 2 per 1,000 tests | Uncommon; covers a range of events, most of which are managed at the time. Reported in the ARTP 2021 statement. | CPET as a predictor of complications in major surgery (PMC)ncbi.nlm.nih.govPublished figure |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
Most people recover within minutes once they stop and cool down, though you may feel tired and your legs may ache for a while. You are monitored briefly until your heart rate and breathing settle. There is usually no lasting effect and you can go home the same day.
- Tiredness and aching legs for the rest of the day.
- Feeling out of breath and hot during and just after the test.
- A briefly pounding or fast heartbeat that settles as you recover.
- Small marks where the ECG electrodes were attached.
Aftercare
- Cool down properly and stay until the team is happy your heart rate and breathing have settled.
- Restart any medicines you were asked to pause, as advised.
- Drink fluids and avoid further strenuous exercise for the rest of the day.
- Use your reliever inhaler as advised if you feel wheezy afterwards.
- Ask when and how you will get your results and who will explain them.
- Seek urgent help if you have chest pain, severe breathlessness, palpitations or feel faint after going home.
- Mention any symptoms you had during the test when you discuss the results.
- Loose, comfortable clothing and suitable footwear
- Advice on which medicines to take or pause
- A list of all your medicines and any inhalers
- A note of symptoms such as chest pain, palpitations or blackouts
- Avoided a heavy meal, caffeine, alcohol and smoking beforehand
- Someone to accompany you if you are anxious or have far to travel
- Questions about what the results will be used for
⚠ Get urgent help if…
- Chest pain, pressure or tightness during or after the test — tell the team immediately or call 999.
- Severe breathlessness that does not settle with rest or your reliever inhaler — seek urgent help.
- Palpitations, a markedly irregular heartbeat, or feeling faint or collapsing — call 999.
- Lips or fingertips turning blue, or feeling drowsy or confused — call 999.
- Persistent dizziness, nausea or feeling generally very unwell after the test.
- New or worsening symptoms in the hours after going home — seek medical advice.
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
CPET produces several measurements, including your peak oxygen uptake (often written as peak VO2) and your anaerobic threshold, alongside how your heart rate, blood pressure, ECG, oxygen levels and breathing responded to exercise. A specialist interprets these together to judge your fitness and how your heart and lungs cope with effort.
Before surgery, the results help weigh up operative risk and plan aftercare, rather than giving a simple pass or fail. When investigating breathlessness, they help point towards a heart, lung or fitness-related cause. CPET does not diagnose a single disease on its own, cannot predict an individual outcome with certainty, and is interpreted alongside your history, examination and other tests.
CPET reflects your fitness and how your heart and lungs respond around the time of the test. Fitness can change with training, illness, treatment or time, so the result is a snapshot. It may be repeated, for example before a later operation, to track changes after treatment or rehabilitation, or if your symptoms change, and your clinician will advise if and when retesting is useful.
Related tests, treatments or support
CPET is often combined with other heart and lung tests, such as an ECG, echocardiogram, breathing tests (spirometry and lung volumes) and sometimes blood tests, to build a fuller picture. Before major surgery it forms part of a wider assessment of your fitness and risk.
Follow-up & long-term care
The measurements are reviewed by a specialist and a report is usually produced within days, then discussed with you or with the team who referred you. The results may inform decisions about surgery, the level of care you need afterwards, further tests, or advice on exercise and treatment.
- CPET may be repeated before a future operation or after treatment or rehabilitation to track change.
- Continue or adjust medicines as advised once any test-day changes are over.
- Follow any exercise or rehabilitation advice given on the basis of the results.
Repeat, follow-on and what comes next
- A test occasionally has to be stopped early or repeated if you cannot reach a useful level of effort.
- CPET may be repeated before a later operation or after treatment or rehabilitation to track change.
- Results are interpreted alongside other tests rather than as a single standalone answer.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A proper cool-down and monitoring until your heart rate and breathing have settled.
- Clear advice on restarting any paused medicines and on what to do if symptoms occur afterwards.
- A specialist report with the results explained in the context of your care.
- A named contact route and escalation plan if you feel unwell after going home.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- Whether the test is part of a wider pre-operative or cardiorespiratory assessment.
- The need for a supervised exercise-testing unit with monitoring equipment and trained staff.
- Who performs and supervises the test and which specialist interprets and reports it.
- Whether a consultation and explanation of results are included.
- Whether other tests (such as an ECG, echocardiogram or breathing tests) are done at the same time.
- The clinic or hospital and its location.
- Whether the test, the monitoring and the specialist report are all included.
- That a properly equipped, supervised unit and trained staff are provided.
- Who will perform and supervise the test and who will interpret and explain the results.
- Whether any other heart or lung tests are bundled in or charged separately.
- What happens, and what it costs, if the test is incomplete and must be repeated.
- The cancellation and rescheduling policy, and what happens if you are unwell on the day.
On the NHS? CPET is available on the NHS, often before major surgery or to investigate breathlessness when clinically indicated; private testing may be used for speed, convenience or as part of a wider fitness or pre-operative assessment.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Not explaining that the test involves exercising to your limit and carries a small but real risk.
- Failing to give clear advice on which medicines to take or pause beforehand.
- Presenting the result as a simple pass-or-fail for surgery rather than part of a risk assessment.
- No clear plan for who will explain the results and what they will be used for.
Marketing red flags
- Selling CPET as a 'VO2 max fitness test' without proper medical screening or monitoring.
- Performing maximal exercise testing outside a properly equipped, supervised unit.
- Implying the test can guarantee a safe operation or rule out all heart and lung disease.
- Down-playing the need for monitoring, recovery and clear interpretation of results.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Why is this test being done for me, and what decision will it inform?
- Which of my medicines should I take or pause before the test?
- What will happen, and how will I be monitored, if I have a heart or lung condition?
- What do my results mean for my operation, my aftercare or my breathlessness?
- Will the test need to be repeated, for example after treatment or before surgery?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my test, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this test not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Why have I been asked to do a CPET before my operation?
Is the test safe?
How hard will I have to exercise?
What is the mask for?
Should I take my usual medicines?
Will the test tell me exactly what is wrong?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: ARTP statement on cardiopulmonary exercise testing 2021 (PMC) Cardiopulmonary Exercise Testing — StatPearls (NCBI) CPET — a beginner's guide to the nine-panel plot (PMC) CPET as a predictor of complications in major surgery (PMC) Perioperative CPET — POETTS consensus clinical guidelines, British Journal of Anaesthesia (2018)
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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