Davis J M, Bailey S P
Department of Exercise Science, School of Public Health, University of South Carolina, Columbia 29208, USA.
Med Sci Sports Exerc. 1997 Jan;29(1):45-57. doi: 10.1097/00005768-199701000-00008.
Fatigue of voluntary muscular effort is a complex phenomenon. To date, relatively little attention has been placed on the role of the central nervous system (CNS) in fatigue during exercise despite the fact that the unwillingness to generate and maintain adequate CNS drive to the working muscle is the most likely explanation of fatigue for most people during normal activities. Several biological mechanisms have been proposed to explain CNS fatigue. Hypotheses have been developed for several neurotransmitters including serotonin (5-HT; 5-hydroxytryptamine), dopamine, and acetylcholine. The most prominent one involves an increase in 5-HT activity in various brain regions. Good evidence suggests that increases and decreases in brain 5-HT activity during prolonged exercise hasten and delay fatigue, respectively, and nutritional manipulations designed to attenuate brain 5-HT synthesis during prolonged exercise improve endurance performance. Other neuromodulators that may influence fatigue during exercise include cytokines and ammonia. Increases in several cytokines have been associated with reduced exercise tolerance associated with acute viral or bacterial infection. Accumulation of ammonia in the blood and brain during exercise could also negatively effect the CNS function and fatigue. Clearly fatigue during prolonged exercise is influenced by multiple CNS and peripheral factors. Further elucidation of how CNS influences affect fatigue is relevant for achieving optimal muscular performance in athletics as well as everyday life.
随意肌肉运动的疲劳是一种复杂的现象。尽管在正常活动中，大多数人疲劳最可能的解释是中枢神经系统（CNS）不愿意向工作肌肉产生并维持足够的驱动，但迄今为止，相对较少关注中枢神经系统在运动疲劳中的作用。已经提出了几种生物学机制来解释中枢神经系统疲劳。针对包括血清素（5-HT；5-羟色胺）、多巴胺和乙酰胆碱在内的几种神经递质提出了假设。最突出的一种涉及大脑各区域5-HT活性的增加。有力的证据表明，长时间运动期间大脑5-HT活性的增加和减少分别会加速和延迟疲劳，并且旨在在长时间运动期间减弱大脑5-HT合成的营养干预可提高耐力表现。其他可能影响运动疲劳的神经调节剂包括细胞因子和氨。几种细胞因子的增加与急性病毒或细菌感染相关的运动耐力降低有关。运动期间血液和大脑中氨的积累也可能对中枢神经系统功能和疲劳产生负面影响。显然，长时间运动期间的疲劳受多种中枢神经系统和外周因素的影响。进一步阐明中枢神经系统如何影响疲劳，对于在体育以及日常生活中实现最佳肌肉表现具有重要意义。
