Having survived med school, internship, and residency, you probably consider yourself somewhat of an expert in the art of taking naps. Now continuing research is leading to nap-taking advice that sounds counter-intuitive, but apparently works.
In short: If you're feeling drowsy and decide you need a nap, drink a cup of coffee first. The so-called "coffee nap," "caffeine nap," or "nappuccino" works because the caffeine's stimulant effect doesn't kick in immediately. So if you drink the coffee when you're exhausted enough for a nap, you'll still be able to fall asleep. But about twenty minutes later the caffeine will take effect and help you wake up feeling clear-headed.
The combination of sleep and caffeine is doubly efficient at ridding the brain of drowsiness-inducing adenosine molecules. It's kind of like adding a doubleshot of espresso to your coffee bar drink. . . but one of the shots is sleep!