The 6MWT was conducted according to a standardized protocol,
23 using an internal hallway with the 100-foot distance marked
by colored tape on the floor. Participants were told that “the
purpose of this test is to see how far you can walk in six minutes.”
They were then instructed to “walk from end to end of the
hallway at your own pace, in order to cover as much ground as
possible.” Each minute, technicians encouraged the participants
with the standardized statements “You’re doing well” or “Keep up
the good work,” but were asked not to use other phrases.
Participants were allowed to stop and rest during the test, but
were instructed to resume walking as soon as they were able to do
so. The technician used a mechanical lap counter to count the
number of laps completed, and an electronic timer with a buzzer
that sounded 6 min after the walk started. Before the walk started
and at the end of the 6-min walk, participants were shown a
modified Borg dyspnea scale24 printed on a card and asked to
“indicate your current degree of shortness of breath” on a scale of
“0 nothing at all” to “10 very, very severe.” At the end of the
walk, they were asked if they had experienced any of the
following specific symptoms: dyspnea, chest pain, light-headedness,
or leg pain, or any other symptoms.