Abstract
Fatigue is not only a widespread subjective experience but also a complex physiological and pathological state involving multiple organs and systems. Currently, there is no consensus on the definition and classification of fatigue. Based on its causes, this paper categorizes fatigue into sports fatigue, occupational fatigue, and pathological fatigue. It elaborates on the specific manifestations and underlying mechanisms of fatigue in the motor, nervous, cardiovascular, digestive, urinary, endocrine, and reproductive systems, aiming to uncover the intrinsic connections of fatigue phenotypes across different systems. These findings may provide key targets for gene-assisted therapy of fatigue-related complications, thereby establishing a new theoretical foundation for the clinical management of fatigue and related research.