Background: The goal of the 6-min walk test (6MWT) is to enable patients to walk "as far as possible" as a measure of their functional ability. The impact of the specific walk instructions on patient 6MWT performance is unknown.
Methods: Patients with pulmonary arterial hypertension (PAH), idiopathic pulmonary fibrosis (IPF), and other forms of interstitial lung disease (ILD) were recruited to perform four identical 6MWTs with one differing instructional phrase. The standard instruction to walk "as far as possible" was substituted in random order with "as fast as possible," "at your normal pace," or "at a leisurely pace."
Results: Twenty-four patients (10 with PAH, eight with IPF, six with other ILD) were enrolled and completed all four 6MWTs. Patients attained the greatest distance with the fast instruction, exceeding the standard instruction distance by a mean of 52.7 m (P < .001). The mean difference between the fast and standard walks was 41.5 m in the PAH group, 66.5 m in the IPF group, and 53 m in the other ILD group.
Conclusions: Patients do not walk as far as they are able with the standard American Thoracic Society instruction for 6MWT. Changing the wording from "far" to "fast" may facilitate a better effort and greater distance during the test. It is possible that this modified 6MWT instruction may result in improved accuracy and reproducibility, thereby enhancing its clinical and research trial usefulness.
Trial registration: ClinicalTrials.gov NCT01789996.