The biology of human sleep timing, like that of other mammals, changes as we age. As puberty begins, bedtimes and waking times get later. This trend continues until 19.5 years in women and 21 in men. Then it reverses. At 55 we wake at about the time we woke before puberty. On average this is two hours earlier than adolescents. This means that for a teenager, a 7 am alarm call is the equivalent of a 5 am start for a person in their 50s.
However, biology is only part of the problem.
Additional factors include a more relaxed attitude to bedtimes by parents, a general disregard for the importance of sleep, and access to TVs, DVDs, PCs, gaming devices, cellphones and so on, which promote alertness.
Researchers at Brown University in Providence have shown that teenagers need about 9 hours of sleep per night.
Observations at a school in Liverpool suggested many were getting just 5 hours on a school night. Unsurprisingly, teachers reported students falling asleep in class.
Evidence that sleep is important is overwhelming.
Research has demonstrated its critical role in memory consolidation and our ability to generate innovative solutions 22 to complex problems. Similar studies have shown that long-term sleep deprivation might be an important factor in predisposing people to diabetes, obesity and hypertension.
Adolescents are increasingly using stimulants to compensate for sleep loss, and caffeinated and/or sugary drinks are the usual choice. The half-life of caffeine is 5 to 9 hours. So a 28 caffeinated drink late in the day delays sleep at night. Tiredness also increases the possibility of taking up smoking.
In the US, the observation that teenagers have 31 biologically delayed sleep patterns compared to adults has led several schools to start the school day at a later time. An analysis of the impact of this decision by the University of 34 Minnesota found that academic performance was enhanced, as was attendance. Sleeping in class declined, as did self-reported depression.
In the UK, a specific high school instituted a 10 am start in 2009 and saw an improvement in academic performance. However, a later start by itself is not enough.
Society in general, and teenagers in particular, must start to take sleep seriously. Sleep is not a luxury or an indulgence but a fundamental biological need.
Russell Foster. Why teenagers really do need an extra hour in
bed. April 22, 2013. Internet: <www.newscientist.com> (adapted).
Judge the following item according to the text.
In the sentence “Society in general, and teenagers in particular, must start to take sleep seriously”, the verb “must” can be correctly replaced with should without changing in the meaning of the text.
