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 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 study by the same group that showed that staying up all night reduced students’ ability to learn by nearly 40%, a consequence, the study said, of brain regions shutting down because of sleep deprivation.
‘Sleep not only rights the wrongs of prolonged wakefulness but, at a neurocognitive level, it moves you beyond where you were before you took a nap,” said Matthew Walker at the University of California, Berkeley.
The findings may explain why our ability to learn falls as we age, because people sleep less as they grow older.Walker’s steam recruited 39 students for the study and divided them into two groups.
At midday the volunteers took part in a learning test designed to exercise a region of the brain called the hippocampus, which is involved in storing memories.
Two hours later one of the groups settled down for a siesta while the other group stayed awake. Later that afternoon, at 6pm, both groups took part in a second round of learning tests.
Those who had napped for an hour not only performed better than the group that stayed awake, they also scored better than they did in the first tests.
The findings suggest that sleep clears the brain’s short-term memory and makes room for new facts to be remembered, Walker told the American Association for the Advancement of Science meeting in San Diego.
Previous studies have established that factbased memories are stored temporarily in the hippocampus before they are moved to the prefrontal cortex region of the brain.
‘It’s as though the email inbox in your hippocampus is full and, until you sleep and clear out those fact emails, you’ re not going to receive any more mail.” Walker said. —