Endurance exercise-induced and mental fatigue and the brain.

It appears that the noradrenergic neurotransmitter system hastens central fatigue during prolonged exercise, a finding that coincides with a faster rate of increase in the rating of perceived exertion. Mental fatigue will affect several neurotransmitter systems, with presumably an important role for dopamine and adenosine, in multiple brain regions such as the prefrontal cortex and the anterior cingulate cortex ABSTRACT: In sports and exercise science fatigue is an elusive concept that has important implications in performance during exercise. It has been described in many ways -tiredness, exhaustion, lethargy or weariness - and describes a physical and/or mental state of being tired and lack of energy. Exercise-induced fatigue can be defined as an acute impairment of exercise performance and a distinction has been made between peripheral and central fatigue. Mental fatigue can be defined as a psychobiological state caused by prolonged exertion that has the potential to reduce cognitive as well as exercise performance. Recent studies have given clear indications that brain catecholamines are involved in the onset of fatigue during endurance exercise. Evidence is provided indicating that the noradrenergic neurotransmitter system hastens central fatigue, a finding that coincides with a faster rate of increase in the rating of perceived exertion. Brain neurotransmission is also suggested to play an important role in mental fatigue. Several neurotransmitter systems might be implicated -with the most important role for dopamine and adenosine- in multiple brain regions such as the prefrontal cortex and the anterior cingulate cortex, and the summation of these alterations might explain the impairment in endurance performance in a mentally fatigued state. Obviously, we have to keep in mind that fatigue is a very complex construct, and that besides brain neurochemistry, several other factors play a role in its onset. This article is protected by copyright. All rights reserved.