Limits of Human Endurance

Editor(s): L. van Loon, R. Meeusen NNI Workshop Series (NNIW) Vol.76 , 2013


Nutrition is one of the key factors that modulates exercise performance. In this book, a group of expert scientists discuss the ergogenic properties of various nutritional interventions and present research to show that dietary strategies can be applied to extend the limits of human endurance, lower the risk of illness or injury, and speed recovery rates. More specifically, they discuss recent finding on topics such as caffeine and its effect on the brain, carnitine and fat oxidation, ergogenic properties of beta-alanine, dietary protein and muscle reconditioning, nutrition and immune status, and the importance of proper hydration. 

  • Caffeine, Exercise and the Brain

    Author(s): R. Meeusen, B. Roelands, L. Spriet

    Caffeine can improve exercise performance when it is ingested at moderate doses (3–6 mg/ kg body mass). Caffeine also has an effect on the central nervous system (CNS), and it is now recognized that most of the performance-enhancing effect of caffeine is accomplished through the antagonism of the adenosine receptors, influencing the dopaminergic and other neurotransmitter systems. Adenosine and dopamine interact in the brain, and this might be one mechanism to explain how the important components of motivation (i.e. vigor, persistence and work output) and higher-order brain processes are involved in motor control. Caffeine maintains a higher dopamine concentration especially in those brain areas linked with ‘attention’. Through this neurochemical interaction, caffeine improves sustained attention, vigilance, and reduces symptoms of fatigue. Other aspects that are localized in the CNS are a reduction in skeletal muscle pain and force sensation, leading to a reduction in perception of effort during exercise and therefore influencing the motivational factors to sustain effort during exercise. Because not all CNS aspects have been examined in detail, one should consider that a placebo effect may also be present. Overall, it appears that the performance-enhancing effects of caffeine reside in the brain, although more research is necessary to reveal the exact mechanisms through which the CNS effect is established.

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