here's what ive found so far...
Low levels of caffeine may decrease performance on complex cognitive tasks. To test this hypothesis 63 psychology students participated in a study examining the effects of 45 mg of caffeine on the Stroop task. The participants consumed either a 12-oz (355-ml) can of Coca-Cola or a 12-oz (355-ml) can of caffeine-free Coca-Cola. A short questionnaire was then answered by the participants, after which they completed a computerized version of the Stroop task. We observed that women had slower reaction times than men (p < .001), and that the effects of caffeine were sex specific, having a significant effect only on men (p < .01). We also found a significant main effect of display (p < .001), and an interaction between sex and display (p < .05), which occurred only in the conflict condition of the Stroop task. These sex differences may reflect the lipid-soluble nature of caffeine. The decreased performance in the caffeine group can be explained by the Yerkes-Dodson law.
From:http://www.psichi.org/pubs/articles/article_276.asp
Description of Caffeine (and its effects)
Description of Caffeine (and its effects)
Caffeine is classified as a central nervous system stimulant. Ingested in moderate doses, caffeine can increase alertness; it also can increase the amount of time it takes to fall asleep, cause headaches and nervousness, and reduce fine motor coordination.
Caffeine enters the bloodstream via the stomach and small intestine. Its effects can begin as quickly as 15 minutes after it is ingested. Caffeine stays in the body for hours