We are now well into summer vacation, and it is time for a quiz. How many hours per night does your teen sleep during vacation? How many hours of sleep does your teen get on school nights during the school year?

During the summer most teens get more sleep, staying up later and sleeping much later than they do during the school year. Are teens simply being lazy during the summer?

Most sleep researchers believe that it is impossible to get too much sleep. If teens sleep more during the summer, it is because they need the extra hours of sleep. During the school year, when they are getting less sleep, they are sleep deprived. Sure, teens have to get up early for school, but they could simply go to bed earlier on school nights and get plenty of sleep. Right?

Wrong. The time at which we feel tired for bed is strongly influenced by physiological factors. Some people are morning people and have great difficulty staying up late. Other people are night owls and have trouble getting up early even if they set an alarm. Our culture views morning people as being more virtuous than night people:

Early to bed, early to rise, makes a man healthy, wealthy and wise. The early bird catches the worm.

Being a morning person is not, however, an indication of moral superiority. It reflects one’s biology.

The physiology of typical teens leads them to be night owls. This tendency to stay up late and sleep late is very resistant to change. Researchers have brought teens into the lab and tried everything that is known about shifting sleep cycles in an effort to cause the teens to be ready to sleep at a time that would be more conducive for getting up for school. The researchers were quite unsuccessful.

Three years ago my colleagues and I here at Grove City College began a study on character development that was funded by the Templeton Foundation. In our pilot study we asked parents about their teenagers' many possible problems. We provided a form with a blank space for the parents to tell us about any problem their teen had that we did not ask about. I was surprised by the number of parents who, without any prompting, wrote that their child had problems sleeping. Did our sample have an unusually high number of teens with sleep disorders?

The teens in our sample were probably quite typical. Sleep-research pioneer William Dement has written about when he began studying sleep patterns in Stanford University students in the 1970s. At first he thought that Stanford was recruiting a surprising number of students with the sleep disorder narcolepsy. He later concluded that the students did not have a sleep disorder; they were simply sleep deprived. Teens may appear to have problems with sleep because we force a schedule on them that is not suited to their physiological cycles.

If we send teens to bed early, knowing that they need to get up early for school, most teens will have trouble falling asleep. Indeed the typical teen will feel most productive when adults are beginning to slow down and sleep. When teens are roused for school before their brains have had enough sleep, teens will be less agreeable and will perform less well on cognitive tasks.

In response to research on the need for sleep in adolescents, schools in Edina, Minnesota changed their starting time from 7:25 a.m. to 8:30 a.m. This change of about an hour made significant changes in the students: Absenteeism was reduced. Student behavior problems were reduced. After one year on the new schedule the 11th and 12th grade students scored higher on achievement tests.

Much has been written about how to improve our schools. Suggestions have ranged from smaller classes to uniforms. A simple approach to improving both discipline and academics in schools is to start the school day later. As parents we may find our relationships with our teens improve when we show them some grace with their sleep patterns. Sleeping in during summer vacation or on weekends is not a sign of laziness; it is simply a matter of teen brains striving to get needed sleep.

Dr. Joseph J. Horton is an associate professor of psychology at Grove City College and a researcher on Positive Youth Development with The Center for Vision & Values.