Jump to content

Cardiopulmonary exercise test

Add links
From Wikipedia, the free encyclopedia
This is an old revision of this page, as edited by 202.189.105.117 (talk) at 02:31, 8 April 2025. The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

This sandbox is in the article namespace. Either move this page into your userspace, or remove the {{User sandbox}} template.

Cardiopulmonary exercise test

An illustration of a treadmill cardio exercise test

Cardiopulmonary exercise testing (CPET) is a non-invasive diagnostic assessment that assesses the combined performance of the cardiovascular, respiratory, and musculoskeletal systems during physical exercise.[1] Developed in the early 20th century, CPET has become a gold-standard method for evaluating cardiorespiratory function[2]. It is useful in evaluating individuals' tolerance towards exercise, diagnosing cardiopulmonary diseases and guiding personalized treatment plans.

This test involves continuously monitoring key physiological responses, such as heart rate, blood pressure, oxygen consumption and ventilation patterns while the patient performs gradually increasing exercise intensity, typically on a treadmill or cycle ergometer[3][4]. Advanced data analysis is also incorporated as a part of CPET. It helps clinicians interpret how the body responds to physical stress, identifying abnormalities that may not be apparent at rest.

However, CPET may not be suitable for high-risk patients, such as those recovering from a recent heart attack (myocardial infarction) or experiencing acute respiratory failure.[5] It should always be conducted under medical supervision, particularly for individuals with known cardiovascular conditions.[5]

History

The origins of cardiopulmonary exercise testing (CPET) trace back to the early 20th century, when scientists first began systemically studying the body's physiological responses to physical exertion. A key breakthrough came in the 1920s, when researchers first recognized that measuring oxygen consumption (VO2) during exercise could serve as an indicator of cardiopulmonary function, marking the foundation of modern CPET.[6]

Another major milestone occurred in the 1950s with the introduction of the Douglas bag method, a technique that allowed for precise measurement of gas exchange (oxygen uptake and carbon dioxide output) during exercise, significantly improving diagnostic accuracy.[7] Further progress is made with the advancement of computerized systems in the 1980s, which automated data collection and analysis, enhancing the reliability and clinical utility of the test.[4]

Today, cardiopulmonary exercise testing (CPET) has become a gold-standard diagnostic tool, valued for its ability to identify the underlying causes of exercise intolerance and evaluate integrated cardiopulmonary function. It plays a critical role in the assessment and management of various conditions, including heart failure, chronic obstructive pulmonary disease, and metabolic conditions.[2][8] Cardiopulmonary exercise testing has broad applications across multiple disciplines like sports science, physiotherapy and rehabilitation, and clinical medicine.[9]

Procedure

Cardiopulmonary exercise testing (CPET) systematically evaluates integrated physiological responses through graded exercise while monitoring gas exchange, cardiovascular function, and respiratory dynamics. The standardized protocol employs breath-by-breath analysis[2] to measure oxygen and carbon dioxide uptake and output, alongside respiratory volumes, synchronized with real-time workload data. The progressive increase in workload challenges the cardiovascular and respiratory systems, exposing limitations in oxygen delivery, metabolic efficiency, or ventilatory capacity. The protocol of this test is structured into four distinct phases to assess adaptation to stress.[8]

  1. Resting phase: Before exercise begins, a 2-3 minute baseline period establishes pre-test measurements of heart rate, blood pressure, and respiratory gas exchange values. This data serves as a crucial reference point for interpreting subsequent exercise-induced physiological changes.
  2. Unloaded phase: This phase transits from rest to exercise, typically done by a 2-3 minute period of low intensity exercise, either cycling without resistance on an ergometer or walking at a slow pace on a treadmill. This warm-up period serves multiple purposes: it allows patients to acclimate to the equipment, stabilizes physiological variables, and prepares the body for more intense exertion while minimizing abrupt cardiovascular demands.[10]
  3. Incremental exercise phase: The core of the test involves an 8-12 minute period of progressively increasing workload, referred to as a ramp modality.[2] The ramp protocol is individually tailored based on fitness level.[8] Severely impaired individuals will have a slower increment rate than fitter subjects. Fitter subjects will have a workload increment rate as high as 25 - 30W/minute, while for debilitated patients, 5W/minute may be used.[11] This phase continues until maximal exertion is achieved, determined either by patient symptoms or objective criteria including respiratory exchange ratio (RER). RER is calculated as the ratio of VCO2 to VO2 (RER = VCO2/VO2); when this ratio exceeds 1.15, it indicates maximal metabolic stress.[1][12]
  4. Recovery phase: Following peak exertion, a 3-5 minute active recovery period monitors the body's return to baseline. For cycle ergometer tests, the workload should be kept below 15W.[10] For treadmill tests, a lower speed between 1.0 and 1.6 km/hour should be applied.[10] It allows clinicians to monitor post-exercise stabilization of heart rate, blood pressure, and ventilation. An abnormal recovery profile may indicate underlying cardiovascular or autonomic dysfunction.

CPET is invaluable for diagnosing in a clinical setting. CPET’s holistic analysis distinguishes cardiovascular, respiratory, or metabolic dysfunction, guiding targeted therapeutic strategies.

Analysis

Parameter analysed[1][9][13]

  • Pulmonary metrics: O2 consumption (VO2), CO2 production (VCO2), oxygen saturation in blood (SpO2), minute ventilation (VE)
  • Cardiovascular metrics: Heart rate, blood pressure, ECG-derived contractility
  • Functional capacity: Peak workload (watts/speed) and maximal oxygen uptake

9-panel analysis

In Cardiopulmonary Exercise Testing (CPET), the interpretation relies heavily on the standardized nine-panel display.[1][9] This display arranges key physiological variables across nine coordinated plots to reveal the relationships between different systems during exercise.[3] Each panel highlights specific aspects of cardiopulmonary function, such as ventilatory efficiency, oxygen uptake kinetics.

9-panel analysis of cardiopulmonary exercise test.[1]

The Nine Panels[1][2]:

The nine panels are arranged in order from left to right, from top to bottom. In nine panels, Panel 2,3,5 indicates the cardiovascular system; Panel 1,4,7 shows ventilation; Panel 6,8,9 represents ventilation-perfusion relationships.[1]

  1. VO₂, VCO₂, VE vs. time: Tracks oxygen uptake, CO₂ output, and ventilation, showing exercise response. VE is supposed to increase with workload smoothly. EOV (exercise oscillatory ventilation) is noted.[2]
  2. Heart rate & O₂ pulse vs. time: Monitors heart rate and oxygen delivery efficiency. It shows the maximum cardiac ability to pump blood for oxygen delivery.
  3. VE vs. VCO₂: Measures ventilatory efficiency via the slope of ventilation to CO₂ output.
  4. VE vs. VO₂: Assesses breathing efficiency relative to oxygen use.
  5. VO₂ vs. work rate: Links oxygen uptake to workload, spotting abnormal responses.
  6. VCO₂ vs. VO₂: Marks the anaerobic threshold where CO₂ exceeds O₂ due to lactic acid.
  7. PetO₂ & PetCO₂ vs. time: Reflects lung gas exchange through end-tidal O₂ and CO₂.[2]
  8. VE/VCO₂ & VE/VO₂ vs. time: Indicates gas exchange efficiency. It represents the ventilatory limitations during exercise.
  9. RER vs. time: Shows respiratory exchange ratio (VCO₂/VO₂), highlighting fuel use and anaerobic shift.

Key interpretation

Cardiopulmonary exercise testing provides a multidimensional assessment of cardiovascular, respiratory, and metabolic function during physical exertion. It can provide several key interpretations (integrated information). Below are the critical parameters, arranged in alphabetical order:[14]

  • Anaerobic threshold (AT)

The anaerobic threshold marks the exercise intensity at which energy production of an individual shifts from aerobic respiration (oxygen-dependent) to anaerobic respiration. This transition occurs when oxygen delivery to muscles becomes insufficient to meet demand, leading to lactate accumulation.[2] This threshold can be identified by VCO2 (volume of carbon dioxide exhaled) and VO2 (volume of oxygen exhaled). A sudden increase in VCO2 relative to VO2 signifies the anaerobic threshold.  The anaerobic threshold usually occurs between 47% and 64% of VO2 max, meaning 47-64% of maximum oxygen uptake in the test. [14]

  • Electrocardiographic findings[2][13]

Through this test, we can check the heart contractility during exercise stress, with the heart's recovery after exercise. The ECG should show minimal waveform changes and no significant deviation from normal sinus rhythm. [13]. It gives insight into the stability of cardiac rhythm under stress. [13]

  • Gas exchange efficiency

The ability to oxygenate blood and remove CO2 can also be measured during the test.[2] By increasing the exercise intensity, we expose the maximum efficiency of individuals’ gas exchange efficiency. Especially the appearance of exercise-induced desaturation, which signifies a ventilatory error during exercise with a SpO2 drop of more than 4%. It may indicate potential interstitial lung disease.[15]

  • Peak oxygen uptake

The highest rate of oxygen consumption is achieved during maximal exercise, which reveals the maximal pulmonary capacity during stress. Indicated by a plateau in the VO2 curve. During the plateau, VO2 no longer increases even with progressive increments in exercise workload.[14] The VO2 max will be compared to a predicted value based on age, sex, and height. Decreased VO2 max is defined as a measured value smaller than 85% of the predicted value.[14]

  • EOV (exercise oscillatory ventilation)[13]

It is described as the oscillating frequency of ventilation during exercise. In normal individuals, a continuous linear rise instead of oscillating, an oscillating pattern that persists ≥60% of the exercise test at an amplitude of ≥15% of the average resting value represents potential respiratory conditions.[2][13]

These act as further proof to evaluate if the key indicators match the preliminary diagnosis of the clinicians.

Equipment

Cardiopulmonary exercise testing relies on specialized equipment to collect precise physiological data during controlled physical exertion. The core equipment includes: [16]

  • Cycle ergometer or Treadmill[2]

This equipment determines the exercise modality. While treadmills better simulate natural walking/running patterns, cycling is preferred for patients with balance issues, severe obesity, or orthopedic constraints.[17]

A cycle ergometer is a stationary exercise bike which allows the respondents to pedal the bike under medical supervision. It can measure the amount of work done (in units of watts) by the respondent when he is performing the test. To increase the exercise intensity, the resistance will be increased over time.

The treadmill simulates walking/ running, the speed of which is adjusted incrementally to increase metabolic load in the test.

Spirometers record pulmonary parameters including tidal volume (VT), respiratory rate (RR),  forced expiratory volumes (FEV), and airflow rates.[2] It aids in diagnosing restrictive lung diseases or obstructive lung diseases.[9]

  • Metabolic cart or gas analyzer[16]

This kind of tool is used to measure the composition of exhaled gas, mostly to detect the oxygen concentrations (VO) and carbon dioxide concentrations (VCO2) in exhaled air.[18] This system makes use of infrared CO2 analyzers and zirconium oxide O2 sensors to detect the concentrations.[19] These measurements synchronize with workload data for comprehensive assessment of gas exchange efficiency.

This electrocardiography system continuously tracks cardiac electrical activity, detecting exercise-induced arrhythmias, ischemia, ST-segment changes (a key landmark for contractility error in the heart), or conduction abnormalities. This represents the primary cardiac assessment tool, allowing visualization of cardiac performance.

  • Ancillary equipment[16]

This kind of equipment is not compulsory but is often added to this test to ensure precise measurement and safety. Blood pressure cuffs track systolic and diastolic pressures at 2-3 minute intervals to monitor the blood pressure of the individual in the test.[20] Pulse oximeters measure peripheral oxygen saturation to detect exercise-induced hypoxemia. Safety gear, some bronchodilators, or defibrillators are prepared to address rare complications like asthma in the test.[2]

Before testing, all devices should undergo rigorous calibration by technicians to ensure accurate measurement, with medical supervision mandated throughout.[11]

Contraindications

Although cardiopulmonary exercise testing (CPET) is a well-established diagnostic tool, it carries certain risks depending on the patient's health condition. These risks can be categorised as absolute contraindications (conditions where CPET should not be performed) and relative contraindications(conditions requiring careful risk-benefit assessment before testing).[2][5][16]

Absolute Contraindications[16]

Absolute contraindications involve acute cardiopulmonary conditions that significantly increase the risk of adverse events during exercise. These include:

These conditions compromise cardiopulmonary function, limiting oxygen delivery during exercise and increasing the risk of hypoxemic hypoxia (oxygen deficiency in tissues).

Relative Contraindications[16]

Relative contraindications include chronic conditions that may elevate risk but do not outright prohibit testing. Key examples are:

  • Hypertension – Persistently elevated blood pressure, often linked to endothelial dysfunction(impaired blood vessel dilation due to reduced nitric oxide bioavailability). Chronic hypertension can damage arterial walls, promoting atherosclerosis. [24]
  • Coronary heart disease (CHD) – Atherosclerotic plaque buildup in the coronary arteries, which may rupture during exercise, triggering thrombosis (blood clot formation) and vessel occlusion. This can lead to acute myocardial ischemia or infarction. [24]
  • Pregnancy
  • Symptomatic tachycardia or bradycardia

Both conditions impair cardiovascular efficiency, increasing the strain on the heart and lungs during CPET. And may lead to severe consequences if CPET is in progress.

If the below are observed in the patients during the test, this test needs to be terminated immediately[1].

Clinical significance[2][17]

The cardiopulmonary exercise test is widely used in clinical treatment, from pre-operative risk stratification to determining a specific disease process. CPET is used for many things, such as checking whether your body condition is suitable for having surgery, evaluating how well heart failure treatments are working, or assisting athletes in designing their treatment plans.

  • Prognosis in heart failure, assessing severity and guiding decisions on therapy, device implantation, or transplantation. Monitoring disease progression and treatment efficacy, tracking changes in functional capacity over time.[2]
  • Used in preoperative assessment to evaluate surgical risk, especially in patients with known or suspected cardiopulmonary disease. It could also be used to assess fitness for transplantation, especially determining cardiopulmonary reserve for procedures like heart or lung transplants.[17]
  • Identify the intolerance to exercise of an individual, especially athletes. It could be used to show the cardiopulmonary vascular limitation and to show the improvement in individuals who are in rehabilitation programs.[2][16]

Future directions

More applications of the CPET may appear by combining the results with other medical tests, as well as introducing wearable technology, which makes it more accessible to the public.[25] Future developments include integrating CPET with imaging like echocardiography for detailed cardiac function. Automated interpretation tools can also be incorporated in cardiopulmonary exercise testing in the future, to reduce subjectivity during clinicians' diagnoses.[10]

  1. ^ a b c d e f g h Chambers, D. J.; Wisely, NA. (2019-03-20). "Cardiopulmonary exercise testing-a beginner's guide to the nine-panel plot". BJA education. 19 (5): 158–164. doi:10.1016/j.bjae.2019.01.009. ISSN 2058-5357. PMC 7807922. PMID 33456885.
  2. ^ a b c d e f g h i j k l m n o p q r s Dores, Hélder; Mendes, Miguel; Abreu, Ana; Durazzo, Anaí; Rodrigues, Cidália; Vilela, Eduardo; Cunha, Gonçalo; Gomes Pereira, José; Bento, Luísa; Moreno, Luís; Dinis, Paulo; Amorim, Sandra; Clemente, Susana; Santos, Mário (2024-09-01). "Cardiopulmonary exercise testing in clinical practice: Principles, applications, and basic interpretation". Revista Portuguesa de Cardiologia. 43 (9): 525–536. doi:10.1016/j.repc.2024.01.005. ISSN 0870-2551.
  3. ^ a b Glaab, Thomas; Taube, Christian (2022-01-12). "Practical guide to cardiopulmonary exercise testing in adults". Respiratory Research. 23 (1): 9. doi:10.1186/s12931-021-01895-6. ISSN 1465-993X. PMC 8754079. PMID 35022059.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  4. ^ a b Lawson, Tom; Anderson, Helen (2024-04-04). CPET Made Simple A Practical Guide to Cadiopulmonary Exercise Testing. England: Cambridge University Press (published 2024-04-11). pp. 159–168. ISBN 9781009412889.{{cite book}}: CS1 maint: date and year (link)
  5. ^ a b c "Cardiopulmonary Exercise Testing (CPET) In Adults". Physiopedia. Retrieved 2025-04-02.
  6. ^ "The History of Measuring Oxygen Consumption - VO2 Master". vo2master.com. 2019-12-13. Retrieved 2025-04-03.
  7. ^ Shephard, Roy J. (July 2012). "A Critical Examination of the Douglas Bag Technique". Medicine & Science in Sports & Exercise. 44 (7): 1407. doi:10.1249/MSS.0b013e318253b1c3. ISSN 0195-9131.
  8. ^ a b c Radtke, Thomas; Crook, Sarah; Kaltsakas, Georgios; Louvaris, Zafeiris; Berton, Danilo; Urquhart, Don S.; Kampouras, Asterios; Rabinovich, Roberto A.; Verges, Samuel; Kontopidis, Dimitris; Boyd, Jeanette; Tonia, Thomy; Langer, Daniel; Brandt, Jana De; Goërtz, Yvonne M. J. (2019-12-18). "ERS statement on standardisation of cardiopulmonary exercise testing in chronic lung diseases". European Respiratory Review. 28 (154). doi:10.1183/16000617.0101-2018. ISSN 0905-9180.
  9. ^ a b c d Deborah, Riebe (2018). ACSM's Guidelines for Exercise Testing and Prescription (10th ed.). America: American College of Sports Medicine. pp. 49–69. ISBN 9781496384010.
  10. ^ a b c d Kabbadj, Kaoutar; Taiek, Nora; Hjouji, Wiame El; Karrouti, Oumaima El; Hangouche, Abdelkader Jalil El (2024-10-16). "Cardiopulmonary Exercise Testing: Methodology, Interpretation, and Role in Exercise Prescription for Cardiac Rehabilitation". US Cardiology Review (18): 22.
  11. ^ a b "ATS/ACCP Statement on Cardiopulmonary Exercise Testing". American Journal of Respiratory and Critical Care Medicine. 167 (2): 211–277. 2003-01-15. doi:10.1164/rccm.167.2.211. ISSN 1073-449X.
  12. ^ Malhotra, Rajeev; Bakken, Kristian; D'Elia, Emilia; Lewis, Gregory D. (2016-06-08). "Cardiopulmonary Exercise Testing in Heart Failure". JACC. Heart failure. 4 (8): 607–616. doi:10.1016/j.jchf.2016.03.022. ISSN 2213-1787. PMID 27289406.
  13. ^ a b c d e f Guazzi, Marco; Adams, Volker; Conraads, Viviane; Halle, Martin; Mezzani, Alessandro; Vanhees, Luc; Arena, Ross; Fletcher, Gerald F.; Forman, Daniel E.; Kitzman, Dalane W.; Lavie, Carl J.; Myers, Jonathan (2012-10-30). "Clinical Recommendations for Cardiopulmonary Exercise Testing Data Assessment in Specific Patient Populations". Circulation. 126 (18): 2261–2274. doi:10.1161/CIR.0b013e31826fb946.
  14. ^ a b c d Milani, Richard V.; Lavie, Carl J.; Mehra, Mandeep R.; Ventura, Hector O. (2006-12-01). "Understanding the Basics of Cardiopulmonary Exercise Testing". Mayo Clinic Proceedings. 81 (12): 1603–1611. doi:10.4065/81.12.1603. ISSN 0025-6196.
  15. ^ Hansen, James E.; Sue, Darryl Y.; Wasserman, Karlman (1984). "Predicted Values for Clinical Exercise Testing". American Review of Respiratory Disease. 129 (2P2): S49 – S55. doi:10.1164/arrd.1984.129.2P2.S49. ISSN 0003-0805.
  16. ^ a b c d e f g h Razvi, Yousuf; Ladie, Danielle E. (2025), "Cardiopulmonary Exercise Testing", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 32491809, retrieved 2025-04-02
  17. ^ a b c Balady, Gary J.; Arena, Ross; Sietsema, Kathy; Myers, Jonathan; Coke, Lola; Fletcher, Gerald F.; Forman, Daniel; Franklin, Barry; Guazzi, Marco; Gulati, Martha; Keteyian, Steven J.; Lavie, Carl J.; Macko, Richard; Mancini, Donna; Milani, Richard V. (2010-07-13). "Clinician's Guide to Cardiopulmonary Exercise Testing in Adults". Circulation. 122 (2): 191–225. doi:10.1161/CIR.0b013e3181e52e69.
  18. ^ Williams, B. A.; Gurner, P. J.; Austin, R. B. (1982). "A new infra-red gas analyser and portable photosynthesis meter". Photosynthesis Research. 3 (2): 141–151. doi:10.1007/BF00040712. ISSN 0166-8595. PMID 24458234.
  19. ^ Wasserman, Karlman (2012). Principles of exercise testing and interpretation: including pathophysiology and clinical applications (5th ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. ISBN 978-1-60913-899-8.
  20. ^ Fletcher, Gerald F.; Ades, Philip A.; Kligfield, Paul; Arena, Ross; Balady, Gary J.; Bittner, Vera A.; Coke, Lola A.; Fleg, Jerome L.; Forman, Daniel E.; Gerber, Thomas C.; Gulati, Martha; Madan, Kushal; Rhodes, Jonathan; Thompson, Paul D.; Williams, Mark A. (2013-08-20). "Exercise Standards for Testing and Training". Circulation. 128 (8): 873–934. doi:10.1161/CIR.0b013e31829b5b44.
  21. ^ Ojha, Niranjan; Dhamoon, Amit S. (2025), "Myocardial Infarction", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 30725761, retrieved 2025-04-02
  22. ^ Malek, Ryan; Soufi, Shadi (2025), "Pulmonary Edema", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 32491543, retrieved 2025-04-02
  23. ^ Mirabile, Vincent S.; Shebl, Eman; Sankari, Abdulghani; Burns, Bracken (2025), "Respiratory Failure in Adults", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 30252383, retrieved 2025-04-02
  24. ^ a b Oparil, Suzanne; Acelajado, Maria Czarina; Bakris, George L.; Berlowitz, Dan R.; Cífková, Renata; Dominiczak, Anna F.; Grassi, Guido; Jordan, Jens; Poulter, Neil R.; Rodgers, Anthony; Whelton, Paul K. (2018-03-22). "Hypertension". Nature Reviews. Disease Primers. 4: 18014. doi:10.1038/nrdp.2018.14. ISSN 2056-676X. PMC 6477925. PMID 29565029.
  25. ^ Dores, Hélder; Mendes, Miguel; Abreu, Ana; Durazzo, Anaí; Rodrigues, Cidália; Vilela, Eduardo; Cunha, Gonçalo; Gomes Pereira, José; Bento, Luísa; Moreno, Luís; Dinis, Paulo; Amorim, Sandra; Clemente, Susana; Santos, Mário (2024-09-01). "Cardiopulmonary exercise testing in clinical practice: Principles, applications, and basic interpretation". Revista Portuguesa de Cardiologia. 43 (9): 525–536. doi:10.1016/j.repc.2024.01.005. ISSN 0870-2551.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Cardiopulmonary_exercise_test&oldid=1284514836"