Similar studies have shown higher levels of the hormone ghrelin, which promotes hunger, and lower levels of leptin, which creates a sense of feeling full. The suggestion is that long-term sleep deprivation might be an important factor in predisposing people to conditions such as 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 five to nine hours. So a caffeinated drink late in the day delays sleep at night. Tiredness also increases the likelihood of taking up smoking.
Collectively, a day of caffeine and nicotine consumption, the biological tendency for delayed sleep, and the increased alertness promoted by computer or cellphone use generates what Carskadon calls a perfect storm for delayed sleep in teenagers.
In the United States, the observation that teenagers have biologically delayed sleep patterns compared with adults prompted several schools to put back the start of the school day. An analysis of the impact by Kyla Wahlstrom at the University of Minnesota found that academic performance was enhanced, as was attendance. Sleeping in class declined, as did self-reported depression.
In the U.K., Monkseaton High School near Newcastle instituted a 10 a.m. start in 2009 and saw an uptick 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, enhancing creativity, productivity, mood, and the ability to interact with others.
If you are dependent upon an alarm clock or parent to get you out of bed; if you take a long time to wake up; if you feel sleepy and irritable during the day; if your behavior is overly impulsive, it means you are probably not getting enough sleep. Take control. Ensure the bedroom is a place that promotes sleep—dark and not too warm—don't text, use a computer, or watch TV for at least half an hour before trying to sleep, and avoid bright lights. Try not to nap during the day and seek out natural light in the morning to adjust the body clock and sleep patterns to an earlier time. Avoid caffeinated drinks after lunch.
It is my strongly held view, based upon the evidence, that the efforts of dedicated teachers and the money spent on school facilities will have a greater impact, and education will be more rewarding when, collectively, teenagers, parents, teachers, and school governors start to take sleep seriously. In the universal language of school reports: We must do better.
This article originally appeared in New Scientist.