Automated VO2max calibrator for open-circuit indirect calorimetry systems

Area of Science:

• Physiology
• Biomedical Engineering
• Exercise Science

Background:

• Accurate calibration of indirect calorimetry is crucial for assessing athletes' aerobic power and ventilation.
• Existing calibrators often fail to replicate the high ventilatory flows characteristic of intense exercise.

Purpose of the Study:

• To develop and validate a novel calibrator capable of simulating high aerobic power (VO2max) and ventilatory demands of athletes.
• To assess the accuracy and precision of conventional indirect calorimetry systems using the new calibrator.

Main Methods:

• Fabrication of a VO2max calibrator designed to mimic athlete ventilation and expired gases.
• Testing the calibrator against indirect calorimetry systems measuring expired volume (VE systems) and inspired volume (VI system).
• Comparison of predicted VO2 and ventilation with measurements from conventional systems.

Main Results:

• The calibrator demonstrated excellent absolute accuracy (bias) for VO2 (< 35 mL.min-1) and ventilation (< 0.50 L.min-1).
• Precision for measured VO2, VCO2, and VE BTPS was approximately 1%.
• Gas analyzer accuracy was also confirmed with minimal bias for O2 and CO2 percentages.

Conclusions:

• The developed VO2max calibrator accurately and precisely simulates athlete physiological conditions for calibration purposes.
• This versatile device can be used for routine calibration of most indirect calorimetry systems.
• The findings support improved reliability in assessing athletes' ventilation and aerobic power.