科学一刻 8：00上课太早了吗？

　　Due to their circadian rhythms, high school age students are exceptionally groggy during the early morning hours.

　　Sleepy Teens

　　For many teens, one of the hardest things about high school is having to wake up so early in the morning.

　　It’s well known that during the teen years circadian rhythms begin to change, resulting in teen brains not being capable of falling asleep until around 11 p.m. The signal for teen brains to wake up tends to kick in only around or after 8 a.m.

　　So there’s tension between when high school typically starts and the natural inclination of high school age students to be exceptionally groggy during the early morning hours. According to several studies, the later high school classes start, the better students tend to do.

　　Improving Test Scores

　　One study that looked at more than 9,000 high school students for one semester found that when classes began at 8:35 a.m. or later, grades in math, English, science and social studies were higher on average.

　　Studies focused on students at the Air Force Academy, and high schools in North Carolina had similar results. Generally speaking, all the studies have found that the later school begins, the better students do.

　　So why do many high schools begin so early? Common arguments hold that later start times interfere with after school activities such as sports and jobs. But studies have shown that school districts that have adopted later high school start times don’t encounter many problems along these lines.

　　So if schools want to see students achieve better grades and test scores, experts strongly suggest starting the day a bit later.