Related Experiment Video
Updated: Aug 17, 2026
Exercise Test for Evaluation of the Functional Efficacy of the Pig Cardiovascular System
Published on: May 12, 2023
The 6-minute walk test does not reliably detect changes in functional capacity of patients awaiting cardiac
Craig Cheetham1, Roger Taylor, Valerie Burke
1School of Human Movement and Exercise Science, University of Western Australia, Perth, Western Australia, Australia.
Background:
Peak oxygen consumption (Vo(2)peak) is a strong independent predictor of prognosis in patients with severe chronic heart failure (CHF) and is used to guide optimal timing of transplantation. However, its assessment is relatively expensive and time-consuming and requires sophisticated equipment and highly trained personnel. The purpose of this study was to determine whether changes in 6-minute walk test (6WT) distance, a simple, inexpensive potential alternative measure of functional capacity, can predict changes in Vo(2)peak in patients with severe CHF.
Methods:
Sixteen subjects (ejection fraction 23+/-2%, Vo(2)peak 16.2+/-1.1 ml kg (-1)min(-1)) underwent repeated 6WT and Vo(2)peak assessments that included familiarization and 4 serial measures, 6 weeks apart (baseline and at Weeks 6, 12 and 18). Analysis compared baseline performance with each subsequent testing occasion.
Results:
At baseline, mean (+/-SE) VO(2)peak was 16.3+/-1.1 ml kg(-1) min(-1) and 6WT distance was 458+/-21 m. 6WT and Vo(2)peak were strongly correlated at all timepoints (average r=0.82; all p<0.05). However, mixed model analysis, assessing the capacity of the changes seen in 6WT to predict changes in Vo(2)peak, showed no statistical significance (F=0.11; p=0.74).
Conclusions:
The 6WT is commonly used to assess functional capacity in patients with heart failure. This study demonstrates that, despite a strong cross-sectional correlation with Vo(2)peak, changes in the 6WT are not a reliable predictor of changes in Vo(2)peak within patients. Therefore, the 6WT has limited utility as a serial measure to assess changes in the clinical status of patients with severe heart failure.
