Physical fatigue Fatigue (medical)

physical fatigue, or muscle fatigue, temporary physical inability of muscle perform optimally. onset of muscle fatigue during physical activity gradual, , depends upon individual s level of physical fitness, , upon other factors, such sleep deprivation , overall health. can reversed rest. physical fatigue can caused lack of energy in muscle, decrease of efficiency of neuromuscular junction or reduction of drive originating central nervous system. central component of fatigue triggered increase of level of serotonin in central nervous system. during motor activity, serotonin released in synapses contact motoneurons promotes muscle contraction. during high level of motor activity, amount of serotonin released increases , spillover occurs. serotonin binds extrasynaptic receptors located on axon initial segment of motoneurons result nerve impulse initiation , thereby muscle contraction inhibited.

muscle strength testing can used determine presence of neuromuscular disease, cannot determine cause. additional testing, such electromyography, can provide diagnostic information, information gained muscle strength testing alone not enough diagnose neuromuscular disorders.

people multiple sclerosis experience form of overwhelming lassitude or tiredness can occur @ time of day, duration, , not recur in recognizable pattern given patient, referred neurological fatigue .