A comparison of the 6-minute walk test and symptom limited graded exercise test for phase II cardiac rehabilitation of older adults

Abstract

Background and Purpose: Older adults often find it difficult to bicycle or walk on a treadmill. Therefore we prospectively evaluated whether the 6-minute walk test (6MWT) could be used as a valid substitute for symptom limited graded exercise testing (SLGXT) to determine exercise capacity in a group of cardiovascularly stable older adults after cardiac surgery. Subjects: Ten older adults who had undergone cardiac surgery participated in the study. Methods: The pedaling speed of the SLGXT was 55-60 rpm, beginning at 20 watts and increasing incrementally until exhaustion. Perceived exertion was rated using the Borg rating scale. Four 6MWTs were performed during the same day with a rest periods of 15-60 minutes. The best distance achieved in the four 6MWTs was used in subsequent analysis. Descriptive statistics and Pearson’s correlation coefficients were calculated. Results: Performance at the 6MWT and the SLGXT were highly and significantly correlated (r = .93, p< .001). The maximum heart rate achieved during the best 6MWT and the SLGXT were moderately and significantly correlated (r = .64, p< .009). The correlation between maximum systolic blood pressure during the 6MWT and SLGXT was somewhat lower (r = .52, p< .038). Conclusions: The 6MWT can be used as a valid substitute for ‘the golden standard’ SLGXT to evaluate exercise capacity after phase II rehabilitation of cardiovascularly stable older adults who have undergone cardiac surgery.