When the “post-lunch slump” hits—what’s the right thing to do? Should we pick up a coffee on the way back to our desk, or should we find a quiet place where we can lean back and close our eyes for fifteen minutes?

Napping during the day isn’t considered an option for most of us who live in industrialized countries. It’s even frowned upon in the workplace as a sign of low productivity. But while the so-called “super-achievers” are out on their coffee breaks, researchers say real achievers have discovered a much more effective “pause that refreshes”—the afternoon nap.

Cornell psychologist Dr. James Maas, author of Power Sleep writes that a 20 minute nap in the afternoon actually provides more rest than sleeping an extra 20 minutes in the morning. He also writes that napping, instead of being discouraged, should be considered a part of one’s “daily exercise routine.”

Naps should be performed at mid-day—about eight hours after we wake up—so as to not disturb the natural biorhythm of our sleep-wake cycles. Naps also should be short; definitely no longer than 30 minutes. (Longer naps allow us to settle into deep sleep, from which it is difficult to awaken).

Another nap secret? Don’t worry if you fall asleep or not. Just closing your eyes and relaxing peacefully will be refreshing in itself. The final anxiety to eliminate is concern about over-sleeping. Professional nappers set a timer for 15-30 minutes, which allows them to enjoy the full rest period without looking at the clock.

Next time you feel the post-lunch slump, consider having a glass of water and closing your eyes for 15 minutes. You’ll be surprised how refreshed you feel from your power nap!