Comparison of hallway and treadmill six-minute walk tests

The 6-min walk test (SMWT) performed in the hallway (HW) is used as a clini cal indicator of functional capacity in patients with lung disease. A 6-min walk test utilizing a treadmill (TM) is easier to perform and allows easie r patient monitoring. Therefore, we formulated a standardized TM SMWT proto col and compared the results with those of a HW SMWT. All patients were enr olled in a pulmonary rehabilitation program. Patients with current infectio n, recent change in inhaled medications or oral steroid use, and significan t cardiovascular disease were excluded. Each subject performed three HW SMW Ts and three TM SMWTs assigned randomly on subsequent days. There was a 30- min rest between each walk and at least a 48-h rest between each test day. All patients completed both HW and TM SMWT within 7 d. Supplemental oxygen was utilized or increased if the saturation fell below 88%. The best of the three tests was used for data analysis. Twenty-one subjects completed the protocol. The mean age was 65 st 10.9 yr (range, 35 to 79 yr). Ten subjects were receiving supplemental oxygen. The mean FEV, was 1.07 +/- 0.53 i. The mean HW SMWT distance was 1,228 +/- 255 ft (range, 612 to 1,679 ft) and th e mean TM SMWT distance was 1,060 +/- 389 ft (range, 475 to 1,819 ft), whic h were statistically different (p = 0.01). The mean difference was 168 +/- 280 ft (range, -326 to 743 ft). Oxygen saturation and supplemental oxygen r equirements did not differ significantly. The intra-test variability of the three HW SMWTs was similar to the three TM SMWTs and no significant differ ence in the coefficient of variation was found. A standardized TM SMWT is f easible and allows easier patient monitoring, but there is a statistically significant difference between the HW and TM SMWT distance and therefore th ey are not interchangeable. However, the intratest reproducibility of the T M and HW SMWTs are similar when three walks are performed in a single test session. The role of the TM SMWT in pulmonary rehabilitation requires furth er exploration.