Both, say scientists. Joseph Stromberg, writing for Vox, reports on new research that shows that a hit of caffeine (coffee, not tea or soda, which has less caffeine than coffee), followed by a power nap, is the best way to reenergize for the rest of the day.
Here’s why: “After [caffeine] is absorbed through your small intestine and passes into your bloodstream, it crosses into your brain. There, it fits into receptors that are normally filled by a similarly-shaped molecule, called adenosine.
Adenosine is a byproduct of brain activity, and when it accumulates at high enough levels, it plugs into these receptors and makes you feel tired. But with the caffeine blocking the receptors, it’s unable to do so.”
Adenosine clears from the brain when you sleep. If you snooze for 20 minutes or less, you won’t enter the deep, sluggishness-inducing stages of sleep, you’ll lose some adenosine so the caffeine has fewer of those molecules to compete with, and you’ll wake up just in time for the coffee to kick in. It’s the maximum utility of both sleep and coffee.
The trick, of course, is the timing: This is a high-wire act of downing a hit of caffeine and simultaneously willing yourself to nod off. You have to chug the coffee super fast—think espresso, downed like a shot. Then lie down, shut your eyes, and go to sleep, damnit!
Go to sleep! Go to sleep before the coffee kicks in!
What, you can’t fall asleep when your brain is screaming at you to fall asleep? Oh, too bad. Guess it doesn’t work for you. Still tired? Um, maybe try another cup of coffee.