Cardiorespiratory responses to exercise related to post-stroke fatigue severity

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 severity with oxygen uptake (V) over dotO(2)) at peak exercise and the time constant of (V) over dotO(2) kinetics (tau(V) over dotO(2)) at exercise onset. The secondary objective was to examine the associations between fatigue and cardiorespiratory variables potentially affecting (V) over dotO(2) 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 (range 27-42) points. The FSS score was not associated with (V) over dotO(2) at peak exercise during a symptom-limited graded exercise test (rho=-0.264; p=0.224), whereas it was significantly associated with tau(V) over dotO(2) during a submaximal constant-load exercise test (rho=0.530; p=0.009). A higher FSS score also significantly correlated with a longer time constant of cardiac output (CO) kinetics (rho=0.476; p=0.022). Our findings suggest that severe post-stroke fatigue is associated with delayed increases in (V) over dotO(2) and CO at the onset of exercise. Our findings can contribute to the development of an appropriate rehabilitation programme for individuals with post-stroke fatigue.

Automated summary

This study found that the severity of post-stroke fatigue is associated with delayed increases in oxygen uptake (V) over dotO(2) and cardiac output (CO) at the onset of exercise, but not with oxygen uptake at peak exercise.