Despite a similar level of resting hyperinflation (as
measured by residual volume/total lung capacity) to that
seen in subjects with moderate/severe COPD that we have
studied [35] , our asthmatic subjects achieved considerably
higher 6MWDs and reported less dyspnoea at the end of the 6MWT. It is possible that differences in transfer
factor and the magnitude of dynamic hyperinflation
occurring during the 6MWT in patients with asthma
compared to COPD may account for their different performances
in the 6MWT [13, 36] . Further, over 50% of the
study cohort reported that they walked on a regular basis,
possibly contributing to the high 6MWDs.