Tens of thousands of people welcome the stimulative effects of coffee every morning as they prepare for work. Caffeine is a central nervous system stimulant, entering the bloodstream through the stomach and small intestine, and can be found in coffee, tea, chocolate, and soft drinks.
Caffeine is absorbed rapidly, with peak plasma concentration reached within 45-60 minutes. It also clears from the body fairly rapidly, taking about 3-6 hours for blood caffeine concentrations to decrease by one half. The body adapts to caffeine consumption fairly rapidly—usually 4 to 5 days.
Caffeine has recently been removed from the International Association of Athletics Federations (IAAF) banned list of performance enhancing substances as it has been demonstrated that a small amount of caffeine has the same performance enhancing properties as a large dose.
Many articles (http://www.rice.edu/~jenky/sports/caffeine.html), early studies, and research have suggested that caffeine use may benefit endurance sports performance by mobilizing free-fatty acids into the blood stream and sparing glycogen consumption during endurance sports training and competition. However, the University of Michigan Sport Medicine Department contends more recent caffeine studies don't support this theory (Read Sport Medicine bulletin 2004.2: http://www.med.umich.edu/1libr/sma/sma_caffeine_sma.htm) . The report suggests that when caffeine improves endurance, it does so by acting as a stimulant. Unfortunately, the research report referenced was not provided on-line.
The bottom line:
- 1-3 cups of coffee may benefit endurance sport performance, but additional doses have little performance benefits
- Do not try something new on race day
- Thoroughly test use of caffeine in training
- Too much caffeine may lead to an upset stomach and nervousness
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