- Abstract -

Caffeine (1,3,7-trimethyl xantine) is the most widely used behavior influencing substance consumed on earth. It has been used to enhance the physical fitness component (ergogenic aid) in sports. Caffeine enhances performance during both low-intensity endurance events (which last several hours) and high intensity exercise (mainly of short-duration). Possible mechanisms involved include increased fat oxidation, stimulation of the central nervous system activity and/or energy metabolism, decreased perception of pain and attenuation of the elevation in potassium concentration. Also, caffeine delays fatigue and improves the contractile strength of cardiac and skeletal muscles.

The hypoalgesic effect of caffeine might stem from its action on peripheral or central adenosine A1 and A2A receptors, involved in the nociceptive system.

Key words: caffeine, performance, ergogenic aid, hypoalgesic effect, adenosine