Aim: In this study, we aimed to determine the factors related to chronic fatigue in patients without other general medical
conditions. In particular, we tried to determine the relationship between sleep quality and chronic fatigue severity aff ected by
several explanatory factors such as anxiety, depression and emotional stress.
Materials & Methods: We used the data collected from the out-patient fatigue clinic in Seoul National Bundang Hospital. Th e study
was conducted from March 3, 2010 to March 2, 2014 and the participants were all fi rst-visit patients at the clinic. We measured
body mass index (BMI) of each patient and evaluated variables including lifestyle (smoking, alcohol consumption, regular exercise),
past medical history, past medication history, quality of sleep, anxiety, depression, stress severity and fatigue severity using a
questionnaire. A total of 214 participants who complained chronic fatigue for more than last 6 months, were evaluated.
Results: Th e factors that showed statistically signifi cant relationship with fatigue severity were regular exercise, anxiety, emotional
stress and global sleep quality. Especially, subjective sleep quality, sleep latency, sleep disturbances, daytime dysfunction in sleep
quality components were signifi cantly related to high fatigue severity, whereas sleep duration, habitual sleep effi ciency, use of
sleeping medication had no relationship with fatigue severity.
Conclusion: Poor quality of sleep was associated with high fatigue severity. Th e major factors that infl uenced fatigue severity were
subjective sleep quality, sleep latency, sleep disturbances and daytime dysfunction.