An anonymous reader writes: Caffeine is a staple of most workplaces — it's rare to find an office without a coffee pot or a fridge full of soda. It's necessary (or at least feels like it's necessary) because it's sometimes hard to stay awake sitting at a desk for hours at a time, and the alternative — naps — aren't usually allowed. But new research shows it might be more efficient for employers to encourage brief "coffee naps," which are more effective at returning people to an alert state than either caffeine or naps by themselves. A "coffee nap" is when you drink a cup of coffee, and then take a sub-20-minute nap immediately afterward. This works because caffeine takes about 20 minutes to get into your bloodstream, and a 20-minute nap clears adenosine from your brain without entering deeper stages of sleep. In multiple studies, tired participants who took coffee naps made fewer mistakes in a driving simulator after they awoke than the people who drank coffee without a nap or slept without ingesting caffeine.