Prediction of Exercise Capacity and Training Prescription from the 6-Minute Walk Test and Rating of Perceived Exertion

Abstract

Walking tests, such as the 6-min walk test (6MWT), are popular methods of estimating peak oxygen uptake (VO2peak) in clinical populations. However, the strength of the distance vs. VO2peak relationship is not strong, and there are no equations for estimating ventilatory threshold (VT), which is important for training prescription and prognosis. Since the 6MWT is often limited by walking mechanics, prediction equations that include simple additional predictors, such as the terminal rating of perceived exertion (RPE), hold the potential for improving the prediction of VO2max and VT. Therefore, this study was designed to develop equations for predicting VO2peak and VT from performance during the 6MWT, on the basis of walking performance and terminal RPE. Clinically stable patients in a cardiac rehabilitation program (N = 63) performed the 6MWT according to the American Thoracic Society guidelines. At the end of each walk, the subject provided their terminal RPE on a 6–20 Borg scale. Each patient also performed a maximal incremental treadmill test with respiratory gas exchange to measure VO2peak and VT. There was a good correlation between VO2peak and 6MWT distance (r = 0.80) which was improved by adding the terminal RPE in a multiple regression formula (6MWT + RPE, R2 = 0.71, standard error of estimate, SEE = 1.3 Metabolic Equivalents (METs). The VT was also well correlated with walking performance, 6MWT distance (r = 0.80), and was improved by the addition of terminal RPE (6MWT + RPE, R2 = 0.69, SEE = 0.95 METs). The addition of terminal RPE to 6MWT distance improved the prediction of maximal METs and METs at VT, which may have practical applications for exercise prescription.

Is the Clinical Delivery of Cardiac Rehabilitation in an Australian Setting Associated with Changes in Physical Capacity and Cardiovascular Risk and Are Any Changes Maintained for 12 Months?

“…However, in the majority of Australian cardiac rehabilitation programs, distance-based field testing protocols, such as the six-minute walk test or the incremental shuttle walk test, are the preferred option [7]. Recent research has shown that the addition of final RPE to six-minute walk test distance can improve the estimation of CRF [44]. The use of this methodology by Australian programs may assist clinicians to provide patients with a more precise exercise prescription.…”

Optimal management of patients after acute coronary syndrome

“…If the cardiopulmonary test is not available, a 6-min walking test associated with the terminal evaluation of perceived effort using the Borg scale is a useful tool for the clinician in prescribing exercise. 20 , 21 Subsequent check-ups should be based on the evaluation of the patient’s adherence to the prescribed exercise plan and they should include a brief motivational interview and a complete functional assessment to quantify progresses and readjust the exercise plan based on the needs.…”

Cardiorespiratory Fitness in the Prevention and Management of Cardiovascular Disease

“…Nevertheless, the sensitivity of estimated CRF is highest when maximal exertion (or near maximal, e.g., >85% age-predicted heart rate maximum and/or >17 on a 20 point Borg Rating of Perceived Exertion scale) is achieved, particularly when comparing repeated assessments (e.g., change in CRF) among populations. Several submaximal tests of CRF have been used in clinical and Shorter timed walk tests, such as the 400 meter and 6-minute walk, are readily used in clinical and epidemiological settings to assess physical function status as well as to predict V O 2max with reasonably high accuracy when compared against directly measured V O 2max (e.g., R 2 = 0.71-0.76; SEE <1.5 METs) [35,36]. The choice of performance-based test to assess CRF will depend on available equipment and testing personnel, population being studied, participant burden and safety, and time and budget constraints.…”