Teenagers 30 years ago were polled on their sleep habits, and researchers gleaning the data found that they were sleeping one hour less than their parents’ generation. Teens of the current generation have lost another hour of sleep beyond what the previous generation lost.
School Districts Experiment with Later Start Times
Two school districts in Minnesota consciously chose to change the start time of the secondary schools and requested a study be done by the University of Minnesota on attendance and grades. The Minneapolis and Edina school districts instituted an 8:40 a.m. start time instead of the previous 7:15 a.m. start time.
The researchers found, when they studied the students’ sleep habits, that common bedtimes, weekdays and weeknights, did not change. However, students gained an hour of sleep each night over previous school years. This finding supported medical research that shows that teenagers typically become sleepy around 11:00 p.m.
Attendance in Minneapolis schools improved after the change in statistically significant amounts. The chances were one in a thousand that the improvement came from some cause other than the start time change.
Sleep Deprivation Causes Memory Deficits
Scientists have known for about 80 years that sleep and memory are connected. Sleep deprivation has been shown to cause memory deficits, lack of alertness, and impaired information processing. The idea that sleep deprivation somehow interferes with the retention of new information is not new, but how this occurs has not been clearly understood.
Recent studies at Duke University have shown that new information is replayed or reverberated in the brain for up to 48 hours during sleep cycles. Apparently, interrupting these reverberations will decrease retention of a new memory.
A 1995 study by Dahl and Carskadon showed that teenagers have a need for at least nine hours of sleep each night, as opposed to adults, who need eight hours. Carskadon also showed that teens need more sleep as they go through puberty, rather than less even though they are approaching adulthood.
Successful Experiment for Students in Minnesota
Parents at the Edina schools overwhelmingly approved of the change. Only students with extensive extra-curricular activities that caused morning and evening demands to cancel out the later start time couldn’t take advantage of the time change. Students who had employment or excessive homework also found it difficult to gain from it. Many parents commented that the convenience to students of eating breakfast and preparing for school made several positive changes in behavior and possibly in grades. Researchers found it difficult to compare grades, but perhaps future studies using test scores will be conducted.
Why Schools Start So Early
Transportation is a common reason for the earlier start times. School districts can run the same buses and the same drivers in waves to pick up first the high school or middle school students and later the elementary students. Cost conscious districts are instituting these methods to save money. The problem is that secondary students are being forced into schedules that do not fit their circadian rhythms, the sleep schedule their developing minds and bodies find most comfortable.
School administrators are struggling through these challenging questions as they try to weigh the prospect of spending money for transportation versus student performance. The challenges of budget can overcome the need for later secondary start times. Perhaps future innovations will help schools coordinate start times with the sleep needs of their students.
Resources:
National Institutes of Health:
Brain Activity during Slow-Wave Sleep Points to Mechanism for Memory
University of Minnesota Studies
Eilene Toppin Ording - Eilene Toppin Ording comes from a wide industrial and educational background. A farmer's daughter from Minnesota, Eilene is an active ...
