Sex-Specific Equations to Estimate Maximum Oxygen Uptake in Cycle Ergometry

Abstract

BackgroundAerobic fitness, assessed by measuring VO2max in maximum cardiopulmonary exercise testing (CPX) or by estimating VO2max through the use of equations in exercise testing, is a predictor of mortality. However, the error resulting from this estimate in a given individual can be high, affecting clinical decisions.ObjectiveTo determine the error of estimate of VO2max in cycle ergometry in a population attending clinical exercise testing laboratories, and to propose sex-specific equations to minimize that error.MethodsThis study assessed 1715 adults (18 to 91 years, 68% men) undertaking maximum CPX in a lower limbs cycle ergometer (LLCE) with ramp protocol. The percentage error (E%) between measured VO2max and that estimated from the modified ACSM equation (Lang et al. MSSE, 1992) was calculated. Then, estimation equations were developed: 1) for all the population tested (C-GENERAL); and 2) separately by sex (C-MEN and C-WOMEN).ResultsMeasured VO2max was higher in men than in WOMEN: -29.4 ± 10.5 and 24.2 ± 9.2 mL.(kg.min)-1 (p < 0.01). The equations for estimating VO2max [in mL.(kg.min)-1] were: C-GENERAL = [final workload (W)/body weight (kg)] x 10.483 + 7; C-MEN = [final workload (W)/body weight (kg)] x 10.791 + 7; and C-WOMEN = [final workload (W)/body weight (kg)] x 9.820 + 7. The E% for MEN was: -3.4 ± 13.4% (modified ACSM); 1.2 ± 13.2% (C-GENERAL); and -0.9 ± 13.4% (C-MEN) (p < 0.01). For WOMEN: -14.7 ± 17.4% (modified ACSM); -6.3 ± 16.5% (C-GENERAL); and -1.7 ± 16.2% (C-WOMEN) (p < 0.01).ConclusionThe error of estimate of VO2max by use of sex-specific equations was reduced, but not eliminated, in exercise tests on LLCE.

Influence of central obesity in estimating maximal oxygen uptake

“…The merit of this approach was substantiated by noting that the magnitude of EE of VO 2 max was similar for men and women and that there were no other significant gender differences related to VO 2 max. After having previously developed these equations 12, in this study, we attempted to evaluate the influence of another potential modulator, central obesity, on the EE of VO 2 max. This was based on the assumption that this variable may adversely decrease mechanical efficiency and, consequently, increase the EE.…”

“…As previously described 12, gender-specific equations used to estimate VO 2 max assume that all individuals consume 3.5 mL of oxygen per kg of body weight per minute at rest. However, subjects with increased fat mass may have a higher absolute resting VO 2 17.…”

“…(kg.min) -1 ] was estimated by the gender-specific equations that were previously validated for a similar population in our exercise lab as follows: C-MEN = [maximal workload (watts)/weight (kg)] x 10.79 + 7 and C-WOMEN = [maximal workload (watts)/weight (kg)] x 9.82 + 7 12.…”

Estimation of specific VO2max for elderly in cycle ergometer

“…Following this investigation line, Silva and Araújo (2015) carried out a systematic review study of deep reflection on the estimation equations of VO2max in relation to sex, in which the difference of estimation regarding the gender is configured. This shows the importance of different types of equation, as in the present study, where the estimation equation refers only to male and also with respect to the ergometric instrument preferably, in this case, the cycle ergometer.…”

“…These protocols minimize the risks inherent in maximal effort tests (Silva and Araújo, 2015). Therefore, the aim of the present study was to develop and validate a specific estimation model of VO2max on a cycle ergometer test protocol for elderly men based on submaximal ventilatory thresholds.…”