Late Breaking Abstract - Muscle oxygenation and cardiorespiratory responses during one and two-leg exercise tests in chronic obstructive pulmonary disease

<bold>Background:</bold> Exercise tests are essential to determine exercise capacity in chronic obstructive pulmonary disease (COPD). Due to lower work, one-leg exercise tests (OLET) may be an alternative to two-leg exercise tests (TLET). Impaired muscle oxygenation (SmO₂) in COPD leads to the early onset of leg fatigue during exercise. <bold>Objective:</bold> We aimed to compare SmO₂ and cardiorespiratory responses to OLET and TLET in COPD. <bold>Methods:</bold> Ten males with COPD (age=66±6 years, FEV₁=52±19%) were included. Lung function was assessed. OLET and TLET were performed incrementally at the cycle ergometer. Peak oxygen uptake (VO₂peak) and work rate (Wpeak), ratio of air expired to carbon dioxide volume (V_E/VCO₂), O₂pulse, oxygen saturation (SpO₂), dyspnea and fatigue (modified Borg Scale), and SmO₂ were measured before, during, and after tests. <bold>Results:</bold> VO₂peak, Wpeak, and O₂pulse were lower in OLET than in TLET (p>0.05). There were no significant differences in V_E/VCO₂, SpO₂, dyspnea, fatigue, and SmO₂ during OLET and TLET (p>0.05). <bold>Conclusions:</bold> OLET reveals lower VO₂peak, Wpeak, and O₂pulse despite similar dyspnea, fatigue perception, and SmO₂. Due to its lower workload, tolerable fatigue, and perception of exertion, OLET may be a practical tool for assessing exercise capacity in COPD. <fig><object-id>erj;64/suppl_68/PA611/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>