Technological and Biological Reliability, and Validity of Five Different CPET Systems During Simulated and Human...

Area of Science:

• Exercise Physiology
• Cardiopulmonary Function Assessment
• Biomedical Engineering

Background:

• Cardiopulmonary exercise testing (CPET) systems are crucial for evaluating exercise responses.
• The validity and reliability of popular CPET systems are not well-established.
• Accurate assessment of respiratory variables, substrate use, and energy expenditure is vital in clinical and research settings.

Purpose of the Study:

• To evaluate the validity and between-day reliability of five popular CPET systems.
• To assess technological and biological variability in CPET measurements.
• To compare system performance during simulated and human exercise.

Main Methods:

• Five CPET systems (Vyntus CPX, Oxycon Pro, VO2 Master, KORR, Calibre) were tested.
• A metabolic simulator assessed breath-by-breath gas exchange validity.
• Six participants performed exercise tests on two separate days to assess reliability.

Main Results:

• Absolute percentage errors varied significantly across systems, particularly for substrate and energy expenditure.
• Technological variability for oxygen uptake (V̇O₂) and carbon dioxide production (V̇CO₂) ranged from 0.46% to 4.99%.
• Biological and technological variability contributed substantially to overall measurement variability in human testing.

Conclusions:

• There are substantial differences in the validity and reliability of popular CPET systems.
• System selection impacts the accuracy of respiratory gas, substrate, and energy expenditure measurements.
• Understanding system variability is crucial for interpreting CPET data in research and clinical practice.