BACKGROUND: Exercise capacity in @entity1030 ( @entity1030 ) is limited by both @entity121 . Neural respiratory drive, measured as diaphragm electromyogram (EMGdi) activity expressed as a proportion of maximum (EMGdi%max), quantifies the mechanical load on the respiratory muscles and relates closely to @entity1353 . We tested the hypothesis that end-exercise EMGdi%max would be higher in @entity1 stopping because of @entity1353 than in those limited by leg fatigue. METHODS: EMGdi, ventilation, rate of oxygen consumption (VO2), and ventilatory reserve (ventilation/maximum ventilatory volume ratio [VE/MVV]) were measured continuously in @entity1 with @entity1030 during exhaustive cycle ergometry. EMGdi was measured with a multipair oesophageal catheter passed per-nasally. Differences in physiological variables between groups of @entity1 stopping because of @entity1353 , leg fatigue, or both were assessed with one-way ANOVA. FINDINGS: 23 @entity1 were included (median FEV1, 39% of predicted, IQR 30  0-56  8). End-exercise EMGdi%max was significantly higher in @entity1 stopping exercise because of @entity1353 (n=12, median EMGdi%max 75  7% [IQR 69  5-77  1]) than in those stopping because of leg fatigue (n=8, 44  1 [39  4-63  3]) or both (n=3, 74  1 [63  6-81  2]) (p=0  02). There were no significant differences between the groups in end-exercise ventilation ( @entity1353 25  7 L/min [16  3-32  0] vs leg fatigue 31  5 [20  9-39  6] vs both 22  0 [17  7-35  7]), VO2, (13  4 mL/min per kg [11  6-14  2] vs 12  1 [10  4-14  8] vs 9  4 [9  1-12  4]), or VE/MVV (80  4% [72  6-88  3] vs 57  8 [52  1-92  6] vs 63  9 [34  5-88  9]). INTERPRETATION: These results suggest that @entity1 limited by @entity1353 due to ventilatory constraints can be identified as those reaching near-maximum levels of neural respiratory drive during exercise. Measurement of EMGdi%max during exercise could prove useful in identifying @entity1 whose functional performance would be best optimised by improvment in pulmonary mechanics rather than interventions to train peripheral muscle groups. FUNDING: None.

Neural respiratory drive and symptoms that limit exercise in XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity1353 :: ('MESH:D004417', 'Disease') :: ['breathlessness'] @entity121 :: ('MESH:D009135', 'Disease') :: ['breathlessness and leg muscle fatigue'] @entity1030 :: ('MESH:D029424', 'Disease') :: ['chronic obstructive pulmonary disease', 'COPD']
@entity1030 :: (MESH:D029424,Disease) :: ['chronic obstructive pulmonary disease']
