Mistake: Using It to Replace Cigarettes
What you do: After finally giving up smoking, your French press becomes your new best friend.
How it affects you: Lane says that smoking is one of the few things that can slightly blunt a caffeine buzz. He explains that the chemical by-products of tobacco kick the liver into high gear, which spurs it to metabolize caffeine faster. Because of that, research has shown smokers have a higher caffeine tolerance and need three to four times more than non-smokers to get the same perk-up effects.
What to try: If you're quitting cigarettes, it's important they realize that the same amount of coffee you usually drink could make you feel agitated, irritable and extra-jittery—not a welcome state at any time, but especially when trying to stick to a tough resolution.
Mistake: Drinking It Too Late...in the Morning
What you do: You follow the medical recommendations to finish your mug before 11 a.m.
How it affects you: New research shows that some people have a gene that causes them to metabolize caffeine quickly, while others can take two or three times as long, says Lane. This means that if you're one of those people who are genetically predisposed to be very sensitive to caffeine, the 8-ounce cup you drink in the morning might not be completely out of your system until after your bedtime.
What to try: There isn't an accessible genetic test to find out which kind of coffee metabolizer you are. But if you're doing everything else the sleep docs tell you to do and you're still finding it hard to nod off, make sure you don't have any caffeine for at least 12 hours before you go to bed. (You can track your caffeine consumption using an app like Caffeine Zone 2 Lite)