Quantifying exertional symptoms throughout incremental CPET adds value to peak measurements across the range of COPD severity

<bold>Background:</bold> Isolated measurements of dyspnoea and leg effort at peak exercise may provide an imperfect picture of the actual symptom burden in patients with COPD. <bold>Aim:</bold> To investigate whether assessing submaximal symptom burden across progressively higher exercise intensities adds value to discrete peak symptom scores. <bold>Methods:</bold> After developing sex- and age-adjusted standards for CR 10 Borg dyspnoea and leg effort versus work rate, we used a novel AI-based software (<italic>DyVe-X</italic>) to determine the overall burden of each symptom (best centile of intensity) during incremental cycle ergometry in 354 patients (196 men) with COPD of varied severity. <bold>Results:</bold> Leg effort was the main limiting symptom in 158/354 patients (44.6%); 88 of them (55.7%) showed “severe-to-very severe” (>75th centile) submaximal dyspnoea. Conversely, dyspnoea was the main limiting symptom in 99/354 patients (28.0%): 45 of them (64.18%) showed “severe-to-very severe” submaximal leg effort (<italic>p</italic><0.01) (<bold>upper panel</bold>). Moreover, peak leg effort and dyspnoea typically underestimated their individual submaximal burden (<bold>lower panel</bold>) across GOLD stages (<italic>p</italic><0.01). <fig><object-id>erj;64/suppl_68/OA1955/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> <bold>Conclusions:</bold> Peak scores of dyspnoea and leg effort underestimated the severity of each symptom as measured throughout incremental exercise in COPD. A novel AI-based approach better exposed the actual extension of the overall symptom burden experienced by these patients.