Role of respiratory variables in indirect equation of maximal oxygen consumption

The purpose of this study was to investigate the role of respiratory variable ventilation in improving the VO₂max estimation equation using the Bruce protocol. The subjects of this study were healthy male high school and college students (Age: 21.4±2.6 years, Height: 175.0±6.4 cm, Weight: 71.3±9.5 kg, BMI: 23.0±2.1). VO₂max was measured using the Bruce Protocol (Ferrar et al., 2014), and the maximum oxygen intake was estimated using the formula VO₂max = 14.8 - (1.379 × T) + (0.451 × T²) - (0.012 × T³) (Predicted BRUCE) (Foster et al., 1984). The results showed a significant difference between the actual VO₂max measured by the Bruce Protocol (BRUCE) and the predicted VO₂max (Predicted BRUCE), though there was a significant correlation (r = 0.857). To improve the accuracy of the estimation, a new equation was calculated using multiple regression analysis, incorporating both respiratory variable ventilation (VE) and the Predicted BRUCE values as independent variables (VE+Predicted BRUCE). This new equation showed no significant difference between the actual BRUCE and VE+Predicted BRUCE, with a correlation coefficient of r = 0.862, indicating a significant correlation. In summary, this study found that the accuracy of VO₂max estimation was increased by adding a respiratory variable to the existing estimation formula.