Are you one of the 15% of teenagers who fell asleep in school last year? Was it the boring teacher? The stale air pumping through the heating vents? Or was it just plain tiredness?

According to the National Sleep Foundation, the average teen sleeps about seven hours per night during the school week. Unfortunately, it’s not enough. Researchers say that teens actually need about nine hours per night of sleep to feel refreshed—15% more sleep than adults and pre-teens! The reason why teens need extra sleep? All those hormonal changes, growth spurts, and re-shapings of our bodies require energy—and a lot of growth occurs during sleep.

Researchers have also learned that when teens hit puberty, their sleep cycle becomes “phase delayed.” What this means is that teens start staying up later (it’s harder to fall asleep at night), and also find it harder to wake up in the morning. This wouldn’t be a problem, except that we all know that schools tend to start VERY early these days. A lot of high schools begin classes at 7:20 in the morning! Is it any wonder there are some sleepy students?

Based upon these findings, Edina High School in Minnesota decided to take action. Three years ago, Edina changed its start time from 7:25 a.m. to 8:30 a.m., in an effort to improve students mood and performance. The results? So far so good. Preliminary studies show that the later start time has improved grades and attendance.

What do you think?