Ability of The Cardiorespiratory System to Adapt to Exercise is Impaired in Individuals With Severe Post-Stroke Fatigue

Physical deconditioning after stroke may induce post-stroke fatigue. However, research on this association is limited. Our primary objective was to investigate the associations of post-stroke fatigue with oxygen uptake (⩒O2) at peak exercise and the time constant of ⩒O2 kinetics (τ⩒O2) at the onset of exercise. The secondary objective was to examine the associations between fatigue and cardiorespiratory variables potentially affecting ⩒O2 during exercise. Twenty-three inpatients from a subacute rehabilitation ward were enrolled in this study. The median (interquartile range) Fatigue Severity Scale (FSS) score as a measure of fatigue was 32 (27, 42) points. The FSS score was not associated with ⩒O2 at peak exercise during a symptom-limited graded exercise test (rho = −0.264; p = 0.224), while it was significantly associated with τ⩒O2 during a submaximal constant-load exercise test (rho = 0.530; p = 0.009). A higher FSS score was also significantly correlated with a longer time constant of cardiac output kinetics (rho = 0.476, p = 0.022). These results suggest that the ability of the cardiorespiratory system to adapt to exercise is impaired in individuals with severe post-stroke fatigue. Our findings can contribute to the development of an appropriate rehabilitation program for such individuals.