Teenagers and sleep
There are a number of commonly reported difficulties associated with teenagers’ sleep. Parents often report concerns that their teenager is staying up late at night using his or her computer or i-phone, has difficulty waking in time to go to school, is often tired during the day, and “binge-sleeps” on the weekends. Sleep research shows that to function optimally teenagers need between nine and ten hours of sleep each night, which is actually more sleep than that needed by many younger children. Research has found that 80% of teenagers are failing to get sufficient sleep, and so are likely to be experiencing the effects of chronic sleep deprivation. In addition to the well-known and obvious effects of ongoing sleep deprivation such as problems with concentration, memory and decision making, chronic lack of sleep in adolescence is associated with increased moodiness and aggression, decreased enthusiasm, anxiety, depression and substance abuse problems. All of these factors will have significant impact on quality of life overall, and on academic performance in particular. A recent US study found that insufficient sleep was a common factor in teenagers who received poor to average school marks.
Circadian rhythms
Before considering some particular problems of teenagers and sleep it is helpful to understand some basic information about sleep cycles. The term circadian rhythms refers to biological cycles that underlie our sleep cycle as well as many other daily cycles in our body such as appetite, body temperature and hormone release. In most people these natural cycles are longer than twenty four hours, so that when adults are placed in laboratories with no natural light or clocks, they will begin to go to sleep later each day and get up later each morning. In other words, their circadian rhythms will “free run” at their inherent rate. Under normal circumstances our cycles are reset each day by a range of cues, with time of waking being particularly important. If we allow our circadian rhythm to free run on weekends and holidays by not waking at about the same time as we do during the week, we will tend to go to sleep later and wake later, resulting in the well-known “Monday-itis”, a difficulty alerting ourselves on Monday morning at our usual weekday time.
Sleep phase delay
A particular feature of adolescents’ sleeping patterns has been called ‘sleep phase delay’, and refers to the way in which many adolescents begin to fall asleep one or two hours later at night during their mid-teens. As we have seen above, sleep phase delay is the likely outcome of insufficient sleep cueing, and until fairly recently this phase delay was attributed to increasing academic and social demands, and decreased parental control of sleep behaviour. However, research now suggests that sleep phase delay may in fact be initiated by a biological process associated with puberty, and the corresponding increase in levels of reproductive hormones. The combined effect of our natural tendency to free run at a cycle slightly longer than twenty four hours and this puberty-related sleep phase delay has the effect of making it even more difficult for teenagers to get to sleep at a time that would allow them to achieve sufficient sleep. School and sport routines often require teenagers to wake up earlier than younger children do, when in fact, because of the sleep phase delay, many adolescents would function better if they woke up later.
Melatonin and the problem of screens
Researchers believe that a hormone called melatonin has an important role in our sleep cycles. It is secreted by a small gland near the back of the brain called the pineal gland, and circulates in the body at high levels during darkness, helping to produce sleep. When light signals fall on the retina of the eye, a specific neural pathway from retina to pineal gland causes melatonin production to cease abruptly, resulting in wakefulness. Clearly before the advent of electric lighting, humans would be awake during daylight hours due to the melatonin-suppressing effects of daylight, and would sleep during the hours of darkness when melatonin levels are high.
Our circadian rhythms have been affected by the use of electric lights during the evening, which have some melatonin-suppressing effects, and so delay the onset of sleep beyond sunset. However, in the last decade an additional factor has been thrown into the complex mix of teenage behaviour and sleeping patterns; electronic device use. Research has found that the short wave length blue spectrum light emitted by back lit screens such as computers and i-pads, has a particularly strong melatonin-suppressing effect. With recent progression from larger desk top screens to smaller hand-held devices such as i-phones and tablets, the effect is amplified, because these devices can be used in bed and are held closer to the face, having the effect of bathing the retina in blue spectrum light. Many teenagers use these devices regularly in the evening and in bed, and this may severely disrupt the production of melatonin and so delay the onset of sleepiness. In addition, engaging with social media such as Facebook, and playing electronic games has been shown to have a more stimulating effect on the brain than watching television or listening to music, further compounding the problem.
It is therefore clear that the combination of the biological changes in adolescence and electronic device use can severely affect teenagers’ sleep, and has the capacity to create very significant and chronic sleep deprivation. The sleep phase of some teenagers becomes very significantly delayed, so that they are not falling asleep until 2am or later, and having enormous difficulties waking in time for school or work. This of course has profound effects on all aspects of life and health.
There are a range of psychological strategies to help with sleep phase problems and other aspects of sleep hygiene. If you or your teenager is having difficulties in this area, please consider making an appointment with me so that we can discuss appropriate treatment strategies.