Here is a neurological gulp to go along with my sip on coffee previously espressoed (See my post of Dec. 19, 2007: grounds for insight.).
Your brain continuously creates adenosine, a chemical that scientists believe causes mental fatigue. Caffeine blocks the brain’s adenosine receptors, which counters the chemical’s dulling effects. This stimulating news comes, appropriately enough, from Wired, May 28 at 110-111.
If you drink something caffeinated to increase your alertness, but you do not want to suffer jitters, it is better to drink frequent small doses rather than a mega blast. No venti; several demitasses. Even better, munch some sugary or carbohydrate-rich snack at the same time and enjoy an extra cognitive kick, for “it seems that glucose and caffeine together do more to enhance cognition than either does alone.”