We’ve known for a long time that a short afternoon nap can make a major difference to our work performance, especially if we’re involved in mental work.

Now, a new book by Harvard University sleep expert Dr Sara Mednick, Take a Nap! Change Your Life, describes the simple process of taking a nap as a “lifesaving habit”. She claims that snoozers make fewer mistakes and have boosted brainpower. One of her experiments involved one group taking a nap, another group drinking a mug of coffee (200mg of caffeine), and a control group taking a placebo.

They were then given a series of tasks, including typing and spatial skill tests. The coffee drinkers performed much worse than the placebo takers, while the nappers performed best of all. So the common assumption that coffee will keep us going through the day has probably been fed to us by the coffee industry.

Dr Mednick, a psychologist and research scientist, has accumulated a lot of evidence that a simple siesta in the afternoon is the best medicine for a happier, healthier life. People who sleep for 30 minutes at least three times a week had a 37 percent lower chance of a heart attack, according to a lead researcher from the Harvard School of Public Health.

In another study, recently published in Nature Neuroscience journal, the good doctor put 30 well-rested people through the same set of tasks four times in the course of a day, starting at 9am through to 7pm.

Performance dropped by 50 percent in those who stayed awake all day. However, the volunteers who took an afternoon nap kept up their performance throughout the day.

NASA has also made a contribution. Tests conducted by them show that astronauts who took a brief snooze doubled their alertness even if they were not tired before the nap. They also increased their work productivity by at least 13 percent.

The ideal time to nap apparently is between 1pm and 3pm which enables the most restful kind of sleep pattern for boosting performance.

I suggest you hedge your bets and take a nap now.