High School Second and Third Graders Sleep 5.4 Hours On Average

“Teenagers, go to bed.”

It was found out that the sleeping hours of teenagers of Korea suddenly decrease after entering high school, and their sleeping hours are much less compared to teenagers from other countries.

A psychiatry team led by Professor Yang Chang-gook of Dong-ah Medical School recently researched the hours that 1,457 teenagers from fifth grade in elementary school through third grade of high school spend sleeping.

The result showed that those teenagers spent seven hours sleeping on average. However, after entering high school, their sleeping hours dropped to 6.02 hours. The hours dropped steadily after that. Average high school second graders spent 5.62 hours sleeping and third graders spent 4.86 hours sleeping.

Especially, it was found out that the average sleeping hours of second and third graders of high school, 5.4 hours, was much less than those of the U.S., seven to eight hours, and Japan, where students slept six to seven hours on average.

As for the reasons for this lack of sleep, 31.9% of students answered “early class times,” 25.9 percent answered “entertainment like the Internet and TV,” 18.9 percent answered “assignments,” and 14.9 percent answered “studying at night.” Especially, 53.4% percent of second and third graders of high school answered “early class time,” and 42.6 percent of students answered that they don’t get enough sleep on weekdays.

Sang Hoon Kim corekim@donga.com