The human brain is genetically programmed to become sleepy in the mid-afternoon, creating an energy slump that can serious dent your productivity. This can be a big problem if you're trying to work reasonable hours because if you don't take action, you'll be running at low energy for the rest of the day.

According to WebMD, the source of the energy slump is adenosine, a chemical that your body creates that tells your brain it's time to go to sleep. Adenosine builds up during the day and peaks at mid-afternoon and early evening. There are four ways to counteract adenosine build-up. Unfortunately, all four have disadvantages.

  1. Coffee gives you a jolt because it blocks the adenosine thereby keeping you from feeling sleepy. However, the effect is only temporary and, especially when coffee is sugared, can create a secondary slump that's worse than the original one.
  2. Napping can be problematic because your brain wants you to take a long nap. That's OK if you live in a culture that has an hours-long siesta, but if you're trying to get home at 6PM, you can't afford to spend an hour in dreamland.
  3. Sunlight kills the slump because your body can't produce melatonin when you're in the sun, but as anyone who works in a room with natural light knows, it's not enough, by itself, to kill the slump.
  4. Exercise floods your body with endorphins but, funny thing about energy slumps... it's hard to get yourself to exercise when you're in the middle of one.

Recently, scientists have recommended something called a "coffee nap." Turns out it takes the caffeine in coffee about 20 minutes to get into your bloodstream to counteract the adenosine. Therefore, if you drink a cup of coffee and immediately take a nap, you can get the benefit of both.

A coffee nap, however, will backfire if you don't do it correctly. For example, if you're asleep, caffiene usually won't, by itself, wake you up, so you can easily end up sleeping too long. Therefore, to get the best of all four methods, here's how to take the ultimate coffee nap:

  1. Make a good cup of black coffee, preferably expresso. As long as you're drinking coffee you might as well get all the health benefits. If you don't like black coffee, make an espresso because...
  2. Chug the coffee rather than drink it leisurely. Time is of the essence here. If you drink your coffee at normal speed, it will start flooding your bloodstream before you can get to sleep.
  3. Take a timed, 20-minute power-nap.  Get comfortable and take a nap. If you're in an open plan office, use eyeshades and noise-cancelling headphones. Put the countdown timer and "Power Nap--Do Not Disturb" on your screen.
  4. Take a brisk 5 minute walk, preferably in the sunlight. When the timer goes off, the caffeine will be hitting your system, so you'll actually feel like exercising. You'll now have both endorphins and caffeine flowing into your system.

The above recipe work because endorphins are longer-acting than caffeine so you get a sustained energy boost rather than a temporary one. Also, the sunlight simultaneously interrupts the adenosine, thereby preventing a secondary slump.

Assuming 5 minutes to make the coffee, you've now spent only a 30 minutes to win another 3 to 4 hours of peak performance. That's great trade-off when the alternative is spending that same amount of time running on half-empty.