Caffeine is one of the most widely consumed drugs in the world, taken socially and for its alertness- and performance-promoting actions. Extensive reports assert that caffeine increases alertness and cognitive performance levels and, when taken before exercise, demonstrates ergogenic properties. Caffeine ingestion has been associated with increased performance during endurance submaximal, and acute, high-intensity exercise. The exact mechanism of action for the performance effects of caffeine is unknown, although several physiologically and psychologically based theories exist as to how caffeine achieves increased performance capabilities. This paper outlines the known sites of caffeine activity in the body,and discusses these with respect to the effects of caffeine observed during performance assessments.
aWoolcock Institute of Medical Research, P.O. Box M77, Missenden Road, Camperdown, NSW 2050, Australia
bUnit for Experimental Psychiatry, University of Pennsylvania School of Medicine, 1013 Blockley Hall, 423 Guardian Drive, Philadelphia, PA 19104, USA
Corresponding author
This work was supported by the following grants: Howard Florey Centenary Research Fellowship 307719 from the National Health & Medical Research Council, NSW BioFirst awards, NR04281 from the National Institutes of Health, F49620-00-1-0266 from the Air Force Office of Scientific Research, NASA cooperative agreement NCC 9-58 with the National Space Biomedical Research Institute.
ABSTRACT