Fatigue after stroke: a systematic review of associations with impaired physical fitness

Background Fatigue is a common and distressing post stroke symptom. One important hypothesis is that fatigue after stroke may be triggered by physical deconditioning, which sets up a vicious, self- perpetuating cycle of fatigue, avoidance of physical activity, further deconditioning, and more fatigue. If an association between physical activity and fatigue after stroke could be established, this would provide a rationale for developing a physical activity- based treatment. Aims Systematically review all observational studies, which have measured both fatigue poststroke and one or more measures of physical fitness and/or physical activity at the same time-point and reported the association between fatigue and fitness variables. Method Publications were identified by systematically searching databases MEDLINE, EMBASE, CINAHL, PsychInfo, and Sportdiscus using keywords 'fatigue', 'stroke', 'fitness', or 'activity' and their associated terms or synonyms. Publications that provided data on associations between fatigue in stroke patients and levels of physical activity, cardiorespiratory fitness and/or muscle strength and mass were included. Results Twenty-nine potential studies were retrieved after scrutinizing the titles and abstracts, of which only three fulfilled our inclusion criteria. No association between fatigue and any measures of physical activity or fitness were found. One study did find, through structural equation modeling techniques that fatigue indirectly influences exercise through self- efficacy expectations. Conclusions There is very limited evidence regarding associations between exercise, fitness, and fatigue after stroke. It still remains highly plausible that exercise can have a positive influence on fatigue. Future research should be longitudinal in design.