CARDIOPULMONARY EXERCISE TEST (CPET)

Direct cardiopulmonary exercise testing (CPET) is considered the gold standard of cardiovascular fitness testing. A CPET involves measurement of cardiac and respiratory function whilst the subject exercises up to maximum capacity.

A CPET is a useful tool for:

  • Identifying physical causes for shortness of breath on exertion.

  • Assessing the contribution of cardiac or respiratory pathologies to incapacity.

  • Quantifying the extent of any impairment and thus the prognosis.

  • Assessing the risk to the patient of any potential surgical procedure.

  • Measuring the response to any (e.g., exercise, pharmacological and surgical) intervention.

CPET is a safe test if done properly - adhering to some strict pre-test criterion. The test aim is to determine maximal exercise ability which with athletes could mean exercise up to a point of failure or inability to continue. Maximum ability for people with medical conditions refers to the presence of symptom limits (i.e., HR, BP, RPE, ECG, ventilation, RER indicating the start of physiological overload). We often first do a submaximal stress ECG assessment with medically referred patients. This baseline submax ECG test might include or be followed-up with a breath-by-breath oxygen consumption CPET if we believe it could provide added value to the assessment. As patients’ fitness improves the CPET test has benefit as a health assessment tool and as part of refining the exercise prescription.

The CPET provide the following cardiovascular health and fitness information:

  • Oxygen uptake or VO2max

    (A diminished VO2 (< 18 ml/kg) is sensitive marker of underlying disease in the respiratory, cardiac, and neuromuscular systems)

  • Heart rate responses on exercise

    (Rhythm, and speed - too high or too low within context of O2 exchange might indicate issues with either the lungs or heart)

  • Oxygen pulse

    (Millilitres of O2 per heartbeat which is an indication of stroke volume – low O2 pulse indicate poor left ventricle function)

  • Ventilation

    (i.e., minute ventilation (VE) and size of each breath (VT) – if VO2max is low and ventilation is high it could indicate that something is wrong with the pulmonary system)

  • Carbon Dioxide output

    (Exhaled CO2 (VCO2) is tightly linked to alveolar ventilation. VE/VCO2 is a surprisingly good predictor of all-cause mortality)

  • Respiratory exchange ratio (RER)

    (The RER or VCO2 divided by VO2 provides info on the intensity of exercise at peak effort)

  • Ventilatory equivalents

    (Indication of how well the lungs are working)

  • Anaerobic threshold (AT)

    (The point where anaerobic sources start to become the main source of energy during exercise or the onset of blood lactate accumulation. A low AT predicts poor outcome in major surgery)

  • Respiratory compensation point (RCP)

    (Only present at maximal effort. Moment when ventilation start to exceed what is required to eliminate CO2. A clear RCP is not attainable in presence of lung disease)

  • Oxygen saturation

    (Disorders of the lung are the most common reason for O2 desaturation)

Athletes who excel in endurance sports generally have a high aerobic capacity or VO2max (i.e., 70 to 85 ml/kg). It is not the sole determinant of endurance performance, but it is considered a fundamental measure of physiologic functional capacity for exercise. The AT and RCT points are useful markers for setting training intensities to enhance athletic performance. The RER and AT levels are useful markers to improve if the aim is to improve surgical survival.

Allow 60-90 mins for the entire process including the presentation of results. The exercise part is less than 15 minutes. Preparation Notes – to get the most from the test, it is best not to exercise for 24 hours prior to the test. We also recommend that you avoid food and caffeine 3 hours prior to the test. Water is fine.

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Email: clinic@orakinetics.co.nz  |  Phone: Lukas 020 4065 6902