Scientists say people learn more after a siesta

Curling up for an afternoon nap can improve the brain's ability to learn by clearing out cluttered memory space, psychologists say.

People who nodded off for an hour after lunch performed better in learning tests than those who stayed awake all afternoon, the scientists found.

A study of students revealed that their brains were refreshed by napping only if they entered what is called stage 2 non-REM sleep, which takes place between deep sleep and the dream state, known as REM or rapid eye movement sleep.



The findings support a habit made famous by Sir Winston Churchill, who considered it part of his daily routine to climb into bed at some point between lunch and dinner.

The research follows a recent study by the same group that showed that staying up all night reduced students' ability to cram new facts by nearly 40%, a consequence, they said, of brain regions effectively shutting down through sleep deprivation.

"Sleep not only rights the wrong of prolonged wakefulness but, at a neurocognitive level, it moves you beyond where you were before you took at nap," said Matthew Walker at the University of California, Berkeley.