Validity of Expired Gas Simulation Model during Constant Load Exercise

Abstract

The purpose of this study was to examine the validity of System Dynamics Model (SDM) of expired gas dynamics during constant load exercise. Five healthy males conducted an incremental test to determine maximal oxygen uptake (VO₂max) and anaerobic threshold (AT). Subjects then undertook constant load tests of low intensity (80%AT), middle intensity (100%AT), and high intensity (120%AT) using a cycle ergometer. The SDM of expired gas dynamics was constructed from incremental load test data. Constant load test data was used as the validity criterion of simulation. For simulation of each intensity constant test, simulation of VO₂ and VCO2 showed significantly high determination coefficient (r²>0.7, P<.05). In the comparison of residuals of simulation, no significant differences was seen among work rate constant tests, indicating the robustness of simulation. In conclusion, the simulation of expired gas dynamics used the SD model was valid and robust to constant exercise.