Critical review of the equations predicting 6-minute walking distance in obese subjects

The correlation between the 6-minute walking distance and obesity has been only partially explored. Results obtained from the existing predictive equations are influenced by a variety of factors (health status, severity of obesity, reduced muscle strength and mobility, decreased aerobic capacity, presence of comorbidities). The aim of our study was to verify, compare and discuss the 6MWD predictive capacity of the equations currently available in the literature in a sample of obese subjects. Despite similar study design, the considered articles varied with regard to the number of individuals included and to age range. None of the equations available in the literature was able to accurately predict the six-minute walked distance performed by the obese subjects involved in our study. The six-minute walked distance performed by obese subjects seems to be influenced by other factors than the variables included in the equations from the literature, suggesting that they may not thoroughly capture the complexity of disability in obese people. Future research should be designed in order to validate population-specific equations, by including variables related to clinical, functional, and psychological areas, which are usually impaired in obese individuals.