CPET: reading VO₂max, VT1 and VT2 in the report
Cardiopulmonary exercise testing (CPET) examines how the body responds to exercise. To do this, it measures respiratory gases and other variables. Oxygen uptake, ventilatory thresholds and the respiratory exchange ratio must be assessed together with the protocol and the course of the load.
Distinguishing VO₂peak and VO₂max
VO₂peak is the highest value of oxygen uptake measured in the test. Whether it can be classified as VO₂max depends on test quality and the assessment of maximal effort3. Secondary criteria such as respiratory exchange ratio, maximal heart rate or lactate are only of limited reliability. A single criterion does not prove the maximum2.
Oxygen uptake alone can neither predict a race result nor say anything about movement economy.
Ventilatory and lactate thresholds
VT1 and VT2 are determined from the course of respiratory gases and ventilation4. Lactate thresholds come from other measured variables and model rules. Both kinds of threshold are closely correlated, but systematically different5. Do not treat the values as identical measurements.
If the values differ, this needs professional interpretation. On its own, a difference proves neither a measurement error nor a disease.
Naming RER correctly
RER stands for respiratory exchange ratio, the ratio of carbon dioxide output to oxygen uptake. It cannot simply be equated with the respiratory quotient at cellular level1.
At high loads, bicarbonate buffering and hyperventilation, among other things, affect the value1. Fat oxidation cannot be read directly from it.
The cited ATS/ACCP statement1 describes clinical cardiopulmonary exercise testing. What carries over to sports performance diagnostics are the methodological principles on RER and maximal effort, not automatically clinical cut-off or reference values.
The report in context
Whoever interprets the report professionally takes protocol, calibration, symptoms and other measurements into account. Medical questions must be assessed by someone with the appropriate qualification.
Sources
- 1
American Thoracic Society, American College of Chest Physicians. ATS/ACCP Statement on cardiopulmonary exercise testing. American Journal of Respiratory and Critical Care Medicine. 2003;167(2):211–277.
Position statementDOI 10.1164/rccm.167.2.211PubMed 12524257
- 2
Poole DC, Jones AM. Measurement of the maximum oxygen uptake V̇o2max: V̇o2peak is no longer acceptable. Journal of Applied Physiology. 2017;122(4):997–1002.
- 3
Midgley AW, McNaughton LR, Polman R, Marchant D. Criteria for determination of maximal oxygen uptake: a brief critique and recommendations for future research. Sports Medicine. 2007;37(12):1019–1028.
- 4
Keir DA, Iannetta D, Mattioni Maturana F, Kowalchuk JM, Murias JM. Identification of Non-Invasive Exercise Thresholds: Methods, Strategies, and an Online App. Sports Medicine. 2022;52(2):237–255.
- 5
Dickhuth HH, Yin L, Niess A, Röcker K, Mayer F, Heitkamp HC, et al. Ventilatory, lactate-derived and catecholamine thresholds during incremental treadmill running: relationship and reproducibility. International Journal of Sports Medicine. 1999;20(2):122–127.
Original researchDOI 10.1055/s-2007-971105PubMed 10190774
Specialist information. No medical advice and no substitute for individual assessment by qualified professionals.
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