Respiratory resistance at 5 Hz (A; R5) and at 20 Hz (B; R20), and differential frequency-dependent respiratory resistance at 5 Hz and 20 Hz measured by impulse oscillometry (C; R5–20) from baseline (time 0) and at 4 h and 26 h after the start of the walk in Oxford Street or in Hyde Park for healthy volunteers and participants with COPD or IHD
Data are percentage changes (95% CI). COPD=chronic obstructive pulmonary disease. IHD=ischaemic heart disease. *p<0·05, **p<0·01, ***p<0·001, comparing Oxford Street with Hyde Park. +p<0·05, ++p<0·01, +++p<0·001, compared with timepoint −2 h.