Independent Perspective News

Physicist Albert Einstein had already suggested it: having forty winks after lunch freshens the mind and stimulates creativity. Now, a study carried out by the Department of Psychology of Harvard University in the US adds one more piece of evidence and stresses that a one-hour nap is, at least, "as good" as a complete night of sleep.

The researchers published the study on the last issue of the Nature Neuroscience magazine. They found that volunteers who slept from 60 to 90 minutes in the afternoon (45 personas) had their performances regarding visual learning tasks enhanced as much as those who slept for eight hours at night.

The Harvard psychologists tested the reaction time of volunteers who had to place the position of bars on a screen. All the tests were done at 9 in the morning and at 7 in the afternoon, an again at 9 on the following day. They say the differences were noticeable between those who could snooze and those who agreed not to (28 people). Among the second group, the decline in their performance was noted as soon as the afternoon of the first day.

There's an even more significant detail: the "nappers" who didn't make it to the phase of deep sleep known as REM did not enhance their performance, but they didn't worsen it either, as did those who didn't sleep at night.

On the other hand, the performance of those who did reach the REM phase improved. "This study offers further evidence to state that REM sleep -reached 90 minutes after falling asleep- reinforces the neuronal net and consolidates attention and memory", commented Guillermo Zanniello, director of the Alterations of Sleep Unit of the Italian Hospital.

The 90-minute nap also helped enhance night-sleep. Volunteers who had the visual test at 9 in the morning following to the nap, and again 24 hours later, could remember the task 50 per cent better than those who didn't sleep in the afternoon.

"Up to now, we knew that naps are restorative, especially during its first hour", states Mirta Averbuch, Argentinian delegate at the Latin American Federation of Sleep Medicine. And she added: "There's a debate on how long the ideal nap is. This new Harvard study points out that 90 minutes would be optimum". But, what do you do when you work in the afternoon and live in a big city? "You should have a break between the morning and the afternoon and relax, you shouldn't have lunch at your working place, you should go window-shopping or walking".