Development of a VO2Peak prediction equation in elderly

Abstract

Introduction. Aging decreases aerobic capacity as determined by direct maximal tests (Hassel et al. 2015). There are indirect methods to assess aerobic capacity such as the 6-min walking test (6MWT). Some equations to predict aerobic capacity have been developed from the 6MWT distance; however, there are no equations to predict aerobic capacity in Latin American elderly. Therefore the purpose of this study was to develop an equation to predict peak aerobic capacity (VO2peak) from the 6MWT and anthropometric variables in functional Costa Rican elderly. Methods. Participants were 79 Costa Rican functional elderly (69.5 ± 24.5 yr.). Volunteers were excluded if they presented gait problems. Anthropometric measures included body height, weight, body mass index (BMI), and body fat percentage as measured by dual-energy X-ray absorptiometry. Indirect calorimetry was used to determine VO2peak on a graded exercise test using the modified Balke protocol, and the 6MWT (Rikli & Jones, 1998) to determine total walking distance. Statistical analyses included Pearson’s correlation, repeated measures t-student, Lin’s concordance coefficient and Bland-Altman, and multiple linear regression. Results. The regression equation for Costa Rican elderly from predictor variables is VO2peak = 17.59 + 0.028 (6MWT in meters) – 0.256 (BMI) -2.567(Gender), with an R2 = 0.48 and a standard error of estimation (SEE) = 3.25 ml/kg min. No significant differences between predicted (23.26 ± 3.08 ml/kg min) and measured (22.95 ± 4.45 ml/kg min) VO2peak values were found (p > 0.05). A high correlation between predicted and measured VO2peak values was obtained (r = 0.70, p < 0.01); however, there was a poor concordance between tests according to Lin’s coefficient (r = 0.61). Discussion. Some variables like the body adiposity (Carpio‐Rivera et al. 2015), 6MWD (Fernandes et al. 2016) or the VO2max cannot be predicted using reference equations derived from different kind of populations. The new equation to predict aerobic capacity in Costa Rican elderly explains 48% of the variance and has an acceptable predictive error.