An Equation for the Prediction of Oxygen Consumption in a Brazilian Population

Background:

The equations predicting maximal oxygen uptake (VO_{2max or peak}) presently in use in cardiopulmonary exercise testing (CPET) softwares in Brazil have not been adequately validated. These equations are very important for the diagnostic capacity of this method.

Objective:

Build and validate a Brazilian Equation (BE) for prediction of VO_2peak in comparison to the equation cited by Jones (JE) and the Wasserman algorithm (WA).

Methods:

Treadmill evaluation was performed on 3119 individuals with CPET (breath by breath). The construction group (CG) of the equation consisted of 2495 healthy participants. The other 624 individuals were allocated to the external validation group (EVG). At the BE (derived from a multivariate regression model), age, gender, body mass index (BMI) and physical activity level were considered. The same equation was also tested in the EVG. Dispersion graphs and Bland-Altman analyses were built.

Results:

In the CG, the mean age was 42.6 years, 51.5% were male, the average BMI was 27.2, and the physical activity distribution level was: 51.3% sedentary, 44.4% active and 4.3% athletes. An optimal correlation between the BE and the CPET measured VO_2peak was observed (0.807). On the other hand, difference came up between the average VO_2peak expected by the JE and WA and the CPET measured VO_2peak, as well as the one gotten from the BE (p = 0.001).

Conclusion:

BE presents VO_2peak values close to those directly measured by CPET, while Jones and Wasserman differ significantly from the real VO_2peak.

Oxygen Consumption; Forecasting; Respiratory Function Tests; Population; Brazil