Sports Medicine

, Volume 36, Issue 10, pp 881–909

Central Fatigue

The Serotonin Hypothesis and Beyond
  • Romain Meeusen
  • Philip Watson
  • Hiroshi Hasegawa
  • Bart Roelands
  • Maria F. Piacentini
Review Article

DOI: 10.2165/00007256-200636100-00006

Cite this article as:
Meeusen, R., Watson, P., Hasegawa, H. et al. Sports Med (2006) 36: 881. doi:10.2165/00007256-200636100-00006

Abstract

The original central fatigue hypothesis suggested that an exercise-induced increase in extracellular serotonin concentrations in several brain regions contributed to the development of fatigue during prolonged exercise. Serotonin has been linked to fatigue because of its well known effects on sleep, lethargy and drowsiness and loss of motivation. Several nutritional and pharmacological studies have attempted to manipulate central serotonergic activity during exercise, but this work has yet to provide robust evidence for a significant role of serotonin in the fatigue process. However, it is important to note that brain function is not determined by a single neurotransmitter system and the interaction between brain serotonin and dopamine during prolonged exercise has also been explored as having a regulative role in the development of fatigue. This revised central fatigue hypothesis suggests that an increase in central ratio of serotonin to dopamine is associated with feelings of tiredness and lethargy, accelerating the onset of fatigue, whereas a low ratio favours improved performance through the maintenance of motivation and arousal. Convincing evidence for a role of dopamine in the development of fatigue comes from work investigating the physiological responses to amphetamine use, but other strategies to manipulate central catecholamines have yet to influence exercise capacity during exercise in temperate conditions. Recent findings have, however, provided support for a significant role of dopamine and noradrenaline (norepinephrine) in performance during exercise in the heat. As serotonergic and catecholaminergic projections innervate areas of the hypothalamus, the thermoregulatory centre, a change in the activity of these neurons may be expected to contribute to the control of body temperature whilst at rest and during exercise. Fatigue during prolonged exercise clearly is influenced by a complex interaction between peripheral and central factors.

Copyright information

© Adis Data Information BV 2006

Authors and Affiliations

  • Romain Meeusen
    • 1
  • Philip Watson
    • 2
  • Hiroshi Hasegawa
    • 1
    • 3
  • Bart Roelands
    • 1
  • Maria F. Piacentini
    • 1
    • 4
  1. 1.Department Human Physiology and Sportsmedicine, Faculty of Physical Education and PhysiotherapyVrije Universiteit BrusselBrusselsBelgium
  2. 2.School of Sport and Exercise SciencesLoughborough UniversityLeicestershireUK
  3. 3.Laboratory of Exercise Physiology, Faculty of Integrated Arts and SciencesHiroshima UniversityHigashihiroshimaJapan
  4. 4.Department of Human Movement and Sport SciencesIstituto Universitario di Scienze MotorieRomeItaly
  5. 5.Human Physiology and Sportsmedicine, Faculty LKVrije Universiteit BrusselBrusselsBelgium