The Wall Street Journal explains why so many teens are night owls. In adolescence, the release of the hormone melatonin, which induces sleep, is delayed by about 90 minutes.
At the same time, teens do not become sleepy as early as they did when they were younger children. In addition, adolescents lose sensitivity to morning light while at the same time reacting more to nighttime lighting conditions.
And, if biology were not enough, many young people succumb to the temptations of late night TV viewing and computer use, making it even more difficult to get up in the morning.
The article also points out that just 7.6% of US adolescents actually sleep for a recommended nine or 10 hours, according to a study conducted by CDC researchers last year.
The study of 33 youngsters ranging in age from seven to 11 who were followed over the course of two weeks also revealed that when children did not get enough sleep, they demonstrated more tearful and frustrated behavior and lost their temper more often.
The piece also points out that according to the US National Institutes of Health, children in this age group need about 10 hours of sleep per night.