The 6-min walk test: is it an effective method for evaluating heart failure therapies?

The 6-min walk (6MW) is a self-paced test for measuring functional capacity. Lower 6MW distances have been associated with adverse outcomes in patients with heart failure. The purpose of this article is to describe the history of the 6MW test and to evaluate its reliability, validity, and predictive value as well as the responsiveness of the test to therapies. In the literature we reviewed, reliability was affected by several factors including learning effects and protocol deviations. The 6MW distance was moderately correlated with peak oxygen consumption derived from cardiopulmonary exercise stress testing. In some studies the 6MW distance was predictive of hospitalization and mortality. In pharmacological and cardiac resynchronization trials the 6MW distance did not consistently detect clinical improvements. Despite limitations, the 6MW test is a viable alternative to stress testing for objectively evaluating functional capacity in some settings. We provide recommendations for using the 6MW test in future studies.