For the study,they aimed for at least ten hours of sleep each night during the season.

VOA: special.2010.06.09

A new study found better results in four-year-olds who go to bed around the same time every night and sleep at least eleven hours.

VOA: special.2010.06.09

Adults should try to get seven to eight hours of sleep a night.

VOA: special.2010.06.09

They did fine on just six hours of sleep a day.

VOA: special.2009.08.26