Overworked, not sleeping well or just feeling tired? If you have a spare 15-20 minutes and a place to lie down, we suggest giving a coffee nap a try.

While drinking coffee before a 20-minute nap might sound crazy, science says it is a great way to boost energy. Studies have found that combining caffeine with a nap improves performance more than a coffee or a nap alone.

So how does it work? Coffee naps work by reducing your levels of the sleep-promoting chemical, adenosine, just in time for the caffeine to kick in. After you fall asleep, levels of adenosine drop, allowing the competing caffeine to begin to take over your brain receptors. Once you fall asleep, there is more room in your brain receptors for the caffeine to go to work.

When you’re tired and think that you could use a few minutes of shut-eye, quickly drink a coffee and then immediately lay down and go to sleep. Be sure to set your alarm first to wake up within 20-minutes just in case the caffeine is delayed in kicking in or you will fall into a deep sleep after 30 minutes or more. Once you get into that type of sleep, it’s hard to shake the drowsiness once you wake up.

But how much coffee should you drink before your nap then? Researchers suggest 200 mg of caffeine before napping is around the amount needed to drive you to alertness, wake you up and keep you energized. Even if you do not fall asleep during your nap, that period of rest still proves to be beneficial.

Research also suggests that you should not have your coffee nap within six hours of your usual bedtime, or else the caffeine will hinder that period of rest.

So, the next time you’re feeling groggy and have time for a nap, drink a coffee, set your alarm and lay down for 20 minutes. You might be surprised by how you feel when you wake up!