Wandering off for an afternoon nap might not the best way to impress your boss – but scientists say it could improve your performance at work.

Researchers at the University of Pennsylvania found a short sleep in the afternoon improves people’s thinking and memory skills and makes the brain perform as if it were five years younger.

The team studied 3,000 elderly Chinese people and looked at whether those who frequently took afternoon naps performed better on mental ability tests.

The participants were given recall tasks and some maths problems, as well as being asked to copy drawings of shapes.

Scientists found people who took a nap after lunch did better on the tests than those who did not sleep in the middle of the day. In total, 60 per cent of people in the study slept after lunch, with the average nap time being 63 minutes.

The study suggested an hour was the best length of nap; people who had longer or shorter rests performed up to six time worse on the tasks. Taking an afternoon nap of the right length is so beneficial that it has the same effect as being five years younger, the researchers said.

How sleep can save your life Show all 2 1 /2 How sleep can save your life How sleep can save your life 654082.bin How sleep can save your life 653899.bin Going to bed and getting up at roughly the same time programmes your body to sleep better Rex

They concluded: “The results support the hypothesis that a moderate-duration nap taken during the post-lunch dip is associated with better overall cognition.

“Older adults who did not nap or napped longer than 90 minutes (extended nappers) were significantly more likely than those who napped for 30 to 90 minutes after lunch (moderate nappers) to have lower overall cognition scores.

“This study suggests that absence of napping and too much napping are associated with poorer cognition, but naps of a moderate duration are associated with better cognition and may be an important part of optimizing cognition in elderly adults.”