According to Paul Kelley, a sleep researcher at the University of Oxford, children between the ages of eight and 10 should start school no earlier than 8:30 a.m., 16-year-olds should start at or after 10 a.m., and 18-year-olds at 11 a.m or later.
Adults could benefit from a later start, too. People between the ages of 18 and 55 should be starting work at 10 a.m. or later, Kelley added.
More at link: A sleep expert says we're all getting up too early — and reveals when school and work should startThe age range where we experience the most sleep deprivation is 14 to 24, when we get about two hours too little sleep per night. From age 24 to 30, we get about 1.5 hours too little, and from 30 to 55, we lose about an hour, Kelley told Business Insider. And the effects are cumulative. "Each day of sleep loss is added on to the next, until we have a chance to [sleep in]," Kelley said.