TABLE 4 Slopes of the relationships with breathlessness before and the breathlessness threshold
V′EVT%VCpredEMGdi%maxEMGdi%max/VT%VCpred
Cycle exercise
 Before0 (0–2.3)0 (0–2.6)0 (0–0.9)0 (0–1.2)
 After10.4 (7.0–19.8)9.9 (4.1–31.5)5.7# (3.0–6.6)6.5 (4.7–15.2)
p-value0.00050.10.00050.0005

  • Data are presented as mean (IQR) unless otherwise stated. V′E: minute ventilation; VT%VCpred: tidal volume expressed as a percentage of predicted vital capacity; EMGdi%max: mean root mean square (RMS) diaphragm electromyogram (EMGdi) activity per breath, expressed as a percentage of maximum RMS EMGdi recorded during maximal inspiratory manoeuvres. #: indicates that the slope of the normalised EMGdi%max and breathlessness relationship was significantly less than the slope of the normalised V′E and breathlessness relationships.