[Reference Equations for the 6-Minute Walk Test in Healthy Individuals.]

The six-minute walk test (6MWT) has been broadly used in clinical settings. Several reference equations for prediction of the total distance walked during the test (6MWD) are available in literature. The present review aimed to critically discuss studies, published in Portuguese and English (LILACS, SCIELO, MEDLINE, PUBMED), which evaluated normal values and created reference equations for predicting 6MWD in healthy subjects, comparing them with the results that were recently obtained in Brazilian individuals. Age, sex, weight, height and body mass index were the main demographic and anthropometric features more often correlated with 6MWD. The equations derived from these characteristics were able to explain between 25 and 66% of the total variability in the 6MWD. Unfortunately, the foreign equations were not applicable to the Brazilian population. Even when the 6MWT was performed following strict standardization, the difference in 6MWT performance between foreign and Brazilian individuals remains, indicating the necessity of providing specific reference equations for each population and/or ethnic group. Accordingly, these equations developed in Brazil are probably the most appropriate for interpreting 6MWT performance in Brazilian patients with chronic diseases affecting the exercise capacity. Future studies are necessary with larger sample sizes (e.g. multicentric ones) and randomized design for the reference values of the 6MWD to be considered reliable.