Research progress on exercise fatigue from the perspective of fatigue biomarkers

Exercise-induced fatigue refers to the physiological processes of body functions that cannot be sustained at a specific level during exercise or the inability of the organs to maintain a predetermined level of intensity. Exercise-induced fatigue is a comprehensive physiological process, which is mainly reflected in the body's neuromuscular system and cardiovascular system. The study of fatigue-related physiological responses related to exercise-induced fatigue provides crucial insights into the underlying mechanisms, enables the assessment of fatigue levels, and aids in the formulation of effective recovery strategies. This review summarized the latest advancements in the research of biomarkers associated with exercise-induced fatigue, exploring the mechanisms of various biomarkers, detection methods, and their applications in sports medicine. Studies have shown that energy substances, metabolites, blood bioindicators, central neurotransmitters, free radicals, urine, saliva, etc., are related to exercise-induced fatigue-related biomarkers in human body. Among them, energy-related substances were the first fatigue markers studied, and metabolites in blood or urine were gradually used as biomarkers as research was deepened and testing methods were refined. The presence of central neurotransmitters gradually increased, and researchers gradually emphasized the important role of neurotransmitters in exercise-induced fatigue. Through a comprehensive analysis of relevant literature, this paper aimed to offer guidance for future research directions and promote a more scientific approach to managing exercise-induced fatigue.