Late for School ? Blame Puberty
Posted: May 3, 2008Erractic release of rest hormone in teens leads to sleep deprivation, morning fatigue: Study
Scientists have confirmed what parents of teenagers have always suspected: Adolescents are out of syn with rest of the world.
Most teens probably do not get enough sleep and suffer in their schoolwork because their internal clocks make them night owls, according to a study published some weeks ago.
Researchers in Australia showed that average teenagers misses more than an hour of sleep each night and is forced to wake up two-and-a-half hours earlier than his or her natural rhythms would dictate.
High school students with a late-night “circadian preference”, as the biological-driven cycle is called, reported doing more poorly in school, and feeling more frequently depressed and unhappy.
” For all people, there is a genetic disposition to being either a ‘morning lark’ or a ‘night owl’,”explained lead author Suzanne Warner, a professor at Swineburne University of Technology in Hawthorn, Australia.
But when hormonal changes kick in at the start of adolescence, young people start to stay up later and - given the chance- wake up later, too.
Most of the students in the study were such “evening persons”, she said. ” Teenagers find that they are most alert in the evening and do not feel sleepy until later, and so find it difficult to get enough sleep during the school term.”
The key is melatonin, a hormone that signals to the body that it needs rest and sleep. As teenagers enter puberty, it is released later and later in the evening.
These are also environmental factors that contribute to the problem. Ambient light tends to minimise the amount of melatonin secreted, and the constant use of computers could keep adolescents up past their natural bedtime, even after the lights are turned out.
“Parents can lower the lights an switch off computers and televisions an hour before bedtime,” advised Prof Warner.
In the study, Prof Warner and two colleagues compared slepp patterns of 310 students during a school term and while they were on holiday.
Whereas teenagers slept more tahn nine hours during the shcool breaks, they averaged less than eight hours when hitting the books.
Compared with “morning larks”, “night owls” were more likely to have negative attitudes about themselves, to express feelings of unhappiness and to voice irritation with their classmates, according to the study, published in the Netherlands- based Journal of Adolescence.
They also complained of low energy and ” impaired” daytime functioning.
” For classes that start before 9 am, we have to question whether the students will be alert and able to learn,” said Prof Warner.
Previous research has shown that nine hours is the optimal amount of sleep time for teenagers.
Circadian clocks are found in organisms ranging from bacteria to human beings, and impose a roughly 24 hours schedule on our activities, such as sleeping and eating.
The mechanism controlling these rhythms is found in individual nenrons located in the suprachismatic nuclei inside the brain. Scientists have identified at least one gene that determines whether one’s “clock” will be naturally set for early or late rising.
The same process is involved in jet lag. Warner pointed out. “You could say that a lot of yound perople feel quite jetlagged coming into the school term- it is a very similar feelings, ” she said.
Parents should rethink a tendency to let adolescents set their own bedtime schedule.
Source: Today
