Analysis of the performance of the portable Cortex Metamax 3B gas analysis system in simulated and real workouts with Vietnamese teenagers

The aim of this study was to investigate the performance of the mobile Cortex Metamax 3B (MM3B) automated gas meter in simulated and real workouts involving teenagers. A total of 28 healthy volunteers (13 men, 15 female) were selected with the following characteristics (mean ± SD): age 17.2 ± 3.1; height 167.1 ± 13.5 cm; weight 54.6 ± 10.4 kg. The following equipment were used: Hypermax 3B (breath-by-breath breathing system), Validator for Gas Exchange Systems (VGES), and Douglas-bag technique (DBT). The results have shown that MM3B is stable at the permitted range during 3 hours while monitoring the gas fractions, as well as the VE, VO2, and VCO2 created by GESV, especially at moderate and high metabolic rates (2% deviation and modest physiological significance). MM3B rated both VO2 and VCO2 significantly higher by about 10-17% at moderate and strenuous activity than DBM and at all exercise levels than Oxycon Pro, although without a significant margin of error in VE. Between the two criteria systems, none of the metabolic variables showed any discernible change (DBM and Oxycon Pro). The MM3B provided acceptable data on stability and reliability, but it was decided that without further adjustment for VO2 and VCO2, the data were not valid during moderate and strenuous activity.