'Lots of sleep' boosts your brain
Regular naps and early nights may not be the hallmarks of a wild social life, but they are the smart way to live, research suggests.
Getting lots of sleep - and even nodding off for an hour or two - boosts brain power dramatically, according to scientists.
Conversely, the more hours people spend awake, the more sluggish their minds become, evidence shows.
The findings may even indicate a link between older people sleeping less and suffering "senior moment" memory lapses.
New research by a team of US experts shows that memories are "downloaded" in the brain during a specific phase of sleep.
Scientists believe sleep is needed to clear the brain's short-term memory storage and make space for new information.
"Sleep not only rights the wrong of prolonged wakefulness, but at a neurocognitive level, it moves you beyond where you were before you took a nap," said lead researcher Dr Matthew Walker, from the University of California at Berkeley.
In one recent study the team divided 39 healthy young adults into two groups named "nap" and "no nap".
At noon, all the volunteers were subjected to a rigorous learning task designed to tax the hippocampus - the brain region that helps store fact-based memories.
Two hours later the nap group took a 60-minute siesta while the no nap group stayed awake. Later the same day, at 6pm, participants were given a new round of learning exercises.