A Simple Equation to Estimate Maximal Oxygen Uptake in Older Adults Using the 6 min Walk Test, Sex, Age and Body Mass Index.

Purpose: The 6 min walk test (6MWT) is used in clinical and epidemiological practice as a simple tool to evaluate the maximal aerobic exercise capacity (VOmax). To date, little evidence has been provided regarding regression equation models to predict VOmax in older adults. Therefore, the main purpose of the study was to develop a reference equation to estimate objectively measured VOmax, based on the 6MWT, sex, age and body mass index (BMI).

Patients And Methods: In this observational prospective study, we collected the data from 233 asymptomatic participants aged 60-80 years (52.4% women). VOmax and the 6MWT were measured using standardized protocols. BMI was calculated as weight (kg) divided by height squared (m). To be able to develop the predictive equation for VOmax, we used linear generalized estimating equations (GEE).

Results: Older men performed better in VOmax (30.9 ± 8.8 vs. 26.3 ± 6.3 mL/kg/min, < 0.001) and the 6MWT (673.9 ± 58.7 vs. 642.3 ± 48.0 m, < 0.001), compared to women. VOmax was correlated with the 6MWT ( = 0.71, < 0.001), sex ( = -0.29, < 0.001), age ( = -0.62, < 0.001) and BMI ( = -0.38, < 0.001). The model to predict VOmax included: VOmax (mL/kg/min) = 59.44 - 3.83 *, sex (1-men; 2-women) - 0.56 *, age (years) - 0.48 *, BMI (kg/m) + 0.04 *, and the 6MWT (m) ( = 0.85; = 72.3%, = 3.99 mL/kg/min, < 0.001).

Conclusion: The newly developed regression equation can be a guideline in clinical and epidemiological practice to predict the VOmax in apparently healthy older adults.