1. a) Tidal volume (VT) plotted as a function of ventilation (V′E), and b) exertional dyspnoea intensity (in Borg scale units) plotted as a function of inspiratory reserve volume (IRV), expressed in absolute value, during symptom-limited constant work rate cyc...
a) Tidal volume (VT) plotted as a function of ventilation (V′E), and b) exertional dyspnoea intensity (in Borg scale units) plotted as a function of inspiratory reserve volume (IRV), expressed in absolute value, during symptom-limited constant work rate cycle exercise. Patients who reached a critically low IRV at the VT inflection point (n=6) were compared with those who did not (n=10). Arrows indicate the VT inflection points. Patients who reached a critically low IRV had dynamic hyperinflation with lower inspiratory capacity at peak exercise, which translated to markedly higher dyspnoea intensity (mean Borg rating 7 “very severe”) in this group after the VT inflection point. The dashed vertical line indicates the total lung capacity (TLC). Graphs represent mean values at rest, at isotime, at VT inflection point, and at peak exercise. *: p<0.05 between groups at the same measurement point. Reproduced and modified from [21] with permission.
Jason Weatherald et al. Eur Respir Rev 2017;26:170015
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