Avoid caffeine when you need to be at your sharpest—its effects don’t last. Instead, chew peppermint or cinnamon gum, or suck on peppermint hard candy.
Research at Wheeling Jesuit University in West Virginia found a strong link between the smell of peppermint and improvements in mood, motivation, and athletic performance. That study complements previous research tying the scent of peppermint to enhanced energy levels and cognitive functioning.
Another study at Wheeling found that the smell of cinnamon boosts brainpower and improves mental dexterity.