Prediction Of Maximal Mets And Ventilatory Threshold Using 6-minute Walk Test Distance And The Rating Of Perceived Exertion

Abstract

The 6-minute walk test (6MWT) is a commonly used outcome measure in clinical exercise programs. The utility of predicting aerobic capacity (maxMETs) from the 6MWT is limited, however, due to biomechanical limitations related to maximal walking speed. This limitation also makes it difficult to prescribe training workloads from 6MWT performance. The latest exercise prescription guidelines suggest that threshold-based training may be superior to range-based training in clinical populations. It was hypothesized that the addition of the Rating of Perceived Exertion (RPE) to 6MWT distance could enhance the prediction of maximal METs from the 6MWT and increase its utility as a prescriptive tool. PURPOSE: To develop equations to predict maxMETs and ventilatory threshold ([email protected]) from 6MWT distance and terminal RPE. METHODS: Twenty-nine subjects between 40-76 years of age completed a treadmill VO2max test with direct measurement of respiratory gas exchange to identify maxMETs and [email protected] On a separate day subjects completed a 6MWT. At the conclusion of the 6MWT subjects rated their effort using the 6-20 Borg Scale. MaxMETs and [email protected] were predicted from 6MWT distance (m) and RPE using stepwise regression. The accuracy of the equations were determined using multiple correlation (R), R2, standard error of estimate (SEE), and coefficient of variation (CV). RESULTS: The resultant equations were: MaxMETs=6.428+.013 (6MWT distance)-.398 (RPE); R=.71, R2=.50, SEE=1.3, CV=13% [email protected] = 3.165 + .01 (6MWT distance) - .18 (RPE); R=.59, R2=.35, SEE=1.1, CV=15% CONCLUSION: It was found that maxMETs could be predicted with reasonable accuracy using 6MWT distance and RPE. [email protected] VT was not quite as robust, but the SEE of estimate was within 1.1 METs. These data suggest that the addition of RPE to 6MWT distance may aid in identifying both maximal and sustainable exercise workloads.