Naps should be timetabled for secondary school children, a study by the University of Delaware suggests.
Researchers studied the link between a post-lunch sleep and brain function in early adolescents.
They found that youngsters who napped five to seven days in a week had sustained attention, better nonverbal reasoning ability and spatial memory.
The best amount of time to nap for was found to be between 30 and 60 minutes, but the researchers said not to nap after 4pm.
The researchers were also surprised to find that people who napped more often tended to have better night time sleep.