Six-minute walk test on a special treadmill: Primary results in healthy volunteers

The guidelines approved by the American Thoracic Society in 2002 definitely recognize the six-minute walk test (6MWT) as a useful tool for the evaluation of physical efficiency in individuals with at least moderate chronic obstructive pulmonary disease, heart failure and intermittent dysbasia. So far, the American Thoracic Society has not approved the use of a treadmill to determine the six-minute walking distance (6MWD) because patients are unable to pace themselves on a treadmill. The purpose of our work was to prove that these problems could be avoided if physical efficiency is evaluated with the use of a modified treadmill.

The work evaluates the function of a treadmill able to adjust its speed to the walking speed of healthy volunteers. The evaluation is based on a comparison of the distance covered by the healthy volunteers and the comfort of the test on the treadmill during six minutes with the distance covered and comfort during the same period in a 22-metre-long hallway in 29 healthy volunteers. Non-invasive blood pressure and pulse measurements were taken immediately before and after the test.

The average distance covered during the six-minute period on the treadmill was 57.1 m longer than in the hallway. The comfort of the treadmill test was indicated to be better by 18 subjects, worse by 4 subjects and identical by 7 subjects.

The tests confirm that the speed of the modified treadmill adjusts properly to the walking speed of the healthy volunteers. The hemodynamic effects were identical for the healthy volunteers both in the hallway and treadmill tests. The distance differences were caused by turnarounds in the corridor test. The results obtained with the special treadmill allow us to develop a new method and, at present, provide a basis for a second stage of research comprising subjects with diagnosed heart failure. (Cardiol J 2007; 14: 447-452).