A quick snooze is good for the brain

AFTERNOON naps are good for the brain, as long as they don’t last too long, say U.S. researchers. Based on two years of data from 3,000 men and women aged 65 and over, they found those who often napped for less than 90 minutes a day performed better on cognitive and memory tests.

The worst performers were those who napped for longer than this, according to the study by the Center for Sleep and Circadian Neurobiology at the University of Pennsylvania. One theory is the longer the nap, the greater the likelihood of going into deeper sleep stages, which can leave people groggy when they wake up.