According to an article in this month’s Wired, a little caffeine goes a long way. As the day progresses, your brain produces adenosine which is thought to create mental fatigue. Caffeine blocks the brain’s adenosine receptors, so you don’t lose your focus. But test subjects report that they felt clearheaded and calm-and thus ready for optimal performance-when they consumed small doses of caffeine throughout the day. So skip the Venti French roast and try cups of tea (with its lower dose of caffeine) throughout the day. And have a small high carb snack at the same time: it seems that glucose and caffeine together clear your head better than either does alone. The sacrifices you have to make to keep alert!