Dyspnoea
Dyspnoeamay be an important determinant of the 6MWDin patients with chronic respiratory disease [52–55],
where it reflects both the physiology of exercise limitation [56, 57] and the impact of exercise limitation on
daily life [58]. Dyspnoea scores collected during the 6MWT exhibit good reliability, with the modified Borg
dyspnoea scale [59] (ICCs 0.59–0.92) showing greater reliability than the 15-count dyspnoea scale (ICC 0.66)
and visual analogue scale for dyspnoea (coefficient of variation 0.22) [1]; however, few studies have investigated
these latter measures.