Here’s everything you need to know about coffee at work by Erik Sherman @FortuneMagazine September 29, 2015, 5:08 AM EDT E-mail Tweet Facebook Linkedin Share icons On National Coffee Day, it’s good to reflect how closely work and coffee go together. Heaven knows workers spend enough on it: an estimated average of $1,092 a year. An office without coffee would be a far less productive workplace — or so we think. Here, Fortune takes a look at what research proves to be true about coffee at work. Coffee heightens your powers of perception. Really. If you ever wondered whether your sense of being more alert after a cup of coffee was scientific fact or your own fancy, researchers from the London School of Hygiene & Tropical Medicine say you were right all along. Caffeine “improved concept formation and reasoning … orientation and attention … and perception.” But there was no improvement in verbal functioning and language schools, other than the ability to order, without a trip of the tongue, that “grande, quad, nonfat, one-pump, no-whip mocha.” Drinking coffee can stiffen your moral fiber. According to University of North Carolina researchers, sleep deprived people are more susceptible to social influences, like a boss who wants you to step over ethical lines. Caffeine can serve to give you backbone, “strengthening your self-control and willpower when you’re exhausted,” according to co-author Michael Christian. You’re probably drinking coffee at the wrong time of day. Having a cup the minute you roll out of bed is a mistake. Between 8am and 9am — and noon and 1pm, as well as 5:30pm and 6:30pm — most people have a spike in their level of cortisol, which helps the body metabolize and use sugar and fat for energy. In other words, you’re already revving up. A jolt of caffeine reduces production of cortisol, which is what you really need, and almost makes you more reliant on increasing caffeine intake, starting a vicious circle. So target the caffeine jolt to between 9:30 am and 11:30am, and if you want to keep sailing through the day, have another cup of java between 1:30 to 3:30. If you’re an early bird or sleep in later, just wait an hour after waking before your first coffee. Take a break with coworkers. A study by Massachusetts Institute of Technology researchers found that communal coffee breaks can increase productivity. The “strength of an individual’s social group was positively related to productivity,” according to the study, and that “giving employees breaks at the same time we increased the strength of an individual’s social groups.” But isn’t shmoozing over coffee just a waste of time? No, another study by Emily Hunter, Ph.D., and Cindy Wu, Ph.D., associate professors of management in Baylor University’s Hankamer School of Business, found that when workers take breaks doing something they enjoy, like drinking coffee, it also improved their job satisfaction. If you’re stressed out, don’t drink coffee. If a bad day at work is pushing you over the mental and emotional edge, put down the cup of coffee. A study out of Duke University Medical Center makes it clear that caffeine can elevate your blood pressure and adrenaline levels. When you’re stressed out, there are other ways to find your happy place.