LOSING SLEEP

Sleep deprivation among teens is a silent epidemic that has serious health implications and it’s not all about stress and screen time

Max was a thoughtful, active teen who simply could not sleep. As much as his parents tried to help him, he stayed up late – his mind racing and his body feeling so wound up it was impossible to relax. He tried listening to music, following guided meditations his mum had suggested he install on his phone, and tracking his sleep with the watch his dad got him. Still, everyone else in the house would fall asleep and his mind would ramp up again. His parents worried that he had a real problem, and that his late-night pattern and lack of sleep were starting to affect his mood. During the school week, he woke up early every morning, and felt like he was in a fog. On the weekends, when he didn’t have lacrosse practice, he could sleep until 11am.

Summer came and Max went to sleepaway camp. Leaving his computer, phone, fitness tracker, and every other gadget he owned behind, he took off for the woods with his siblings. Within three nights, the formerly sleep-resistant night owl was falling asleep, deeply and peacefully around 10pm, sleeping a long and restorative night, and waking easily with the group for a full day of activities.

Why? You might assume it was the mental break from school and the hustle of everyday teenage life – and you’d be partially correct. The truth is, though, that the sleep correction Max experienced was as much biological as it was psychological.

Max was experiencing what we call paleo-sleep – sleep in a natural setting, without technology, light, and all the other aspects of modern life – and his body’s internal clock was reset.

Almost without effort, his evolutionary old sleep systems synced and breathed a sigh of relief. Once you understand these natural sleep mechanisms, you’ll see – even without a trip to summer camp – how you can harness these ideas and unleash the power of sleep.

Middle childhood is the sunny springtime

of sleep. When kids are aged six to 10, the resistance to bedtime routines has often faded, nightmares are less frequent, and most school-age kids can go full speed all day long, running, swinging, reading, eating – and then naturally fall into a deep and long sleep. During this time, good sleep becomes the norm in many homes, and parents often forget it was ever a concern.

In adolescence, the pressure begins to build, and clouds of sleep-loss move across the sky. This sweet honeymoon of sleep comes to an end.

In middle school, most kids lose their footing on healthy sleep habits. By age 15 the vast majority are sleep-deprived.

A lab study of 10th graders showed that, when given the opportunity to sleep during the day, nearly half fell directly into REM sleep – a symptom normally associated with the sleep disorder narcolepsy. It took these kids an average of 3.4 minutes to fall asleep when given the chance at 8.30am (a time when the average high schooler might be expected to take a calculus test). A large US study showed that 57 per cent of middle schoolers do not meet the recommended number of hours of sleep, and in high school that rose to 93 per cent.

Meanwhile, the severity of the problem goes largely unnoticed. Many parents don’t realise how sleep-deprived their teen is, and the nature of the mental and physical toll this takes on the body.

Sleep is when growth hormone is secreted, muscles and tissues repair, and neural connections are refined and strengthened. Deep sleep sends soothing signals to the body’s fight or flight system. Healthy sleep gives us an infusion of neuro chemicals like dopamine (the reward chemical) and norepinephrine (akin to the brain’s natural adrenaline), fuelling us with positive energy. Our waking hours, on the other hand, are when stress hormones are higher and the body is taxed.

When teens do not sleep enough, brain and body repair is cut short, positive neurochemicals are dampened, and the scales are tipped toward chronic stress.

Regions of the brain, like the prefrontal cortex that help us regulate emotions, are dulled which is why studies of even partially sleep-deprived people show they become more irritable, volatile, and negative.

A recent study of adolescents in the UK found that teens who slept less at age 15 were significantly more likely to have symptoms of depression and anxiety at age 17 and in their early 20s.

Those diagnosed with depression went to bed later, woke up more during the night, and were more likely to say they felt very sleepy during the day than those without a mental health diagnosis.

We are all discussing teen mental health, but sleep is a glaring hole in this conversation. To effectively address teen mental health is to address sleep.

Do you remember, as a teen, that you

could stay awake into the wee hours and sleep deeply through the morning – sunlight streaming in the windows, neighbourhood dogs barking, and other family members banging pots and pans in the kitchen? Many teens have zero interest in climbing into bed before midnight and can sleep through a fire drill in the early morning.

What’s the reason for this teen nocturnal transformation? It’s not rebellion or laziness – as we once might have thought. The answer starts with an interesting shift in the adolescent sleep clock – a neurological change that sets teenagers on a later rhythm than the rest of us.

What we know about the curious sleep patterns of adolescents began to unfold in the 1970s, with the work of Mary Carskadon and William Dement at California’s Stanford University. To investigate how sleep changes through the pre-teen and adolescent years, the researchers created the Stanford Sleep Camp and embarked on a multiyear study. Starting with a group aged 10, 11 and 12, the researchers organised camp-like activities during the day and measured the kids’ sleep at night. The same kids returned to campus in the summers for several years, giving a longitudinal view of how their sleep developed through adolescence. They expected kids would naturally sleep less as they got older.

They were astounded to see this was not the case at all. At the beginning of the study, the pre-teens slept an average of 9.25 hours of the 10 hours allotted. But every year they returned to sleep camp they continued to sleep the same number of hours. Not only that, when they were younger, after nine or 10 hours of sleep, the kids tended to wake up naturally and easily, and were alert when tested during the day.

The older teenagers, on the other hand, despite also sleeping nine to 10 hours, often had to be woken up in the morning (after an allotted 10-hour sleep period) and were less alert during the day.

It was truly a surprise to see how much the older teens continued to sleep, and even with this long night of sleep, the data seemed to show they were drowsier than their younger counterparts.

Dr Dement wrote that one of his first takeaways from the early years of the sleep camp was just how alert and well rested the pre-teens were. He described them as “like puppies, bursting with energy; at night they slept about 10 hours” and referred to this age as the pinnacle of sleep perfection.

Seeing that the older adolescents, by measures taken in the lab, were sleepier during the day initially led Carskadon and Dement to think that teens might need about an hour more sleep than younger kids. They later revised their thinking to reflect that the drowsiness resulted from the sleep debt these older teens carried (even though they were instructed to sleep for 10 hours a night the week before the lab assessments), as well as the developmental force we’ll explore in a moment – the natural timing shift in the teen sleep clock.

Regardless, the adolescents averaged about nine and a quarter hours at every age. Since these classic studies, much more research has backed up this need for an average of nine to 10 hours per night through adolescence.

This remarkable desire for sleep has amazed scientists and parents alike. In lab studies, researchers have seen just how long teens’ bodies want to sleep, if given the chance. In a later study, Carskadon found that teenagers, studied in the lab for three nights, given an 18-hour opportunity to sleep, slept an average of nearly 12.5 hours the first night (again, a sign of teens making up for lack of sleep) and 10.1 hours by the third night. Most parents tell us they, too, are in awe of their teen’s sleeping powers.

On holidays, (co-author) Heather Turgeon has seen her young adolescent routinely sleep 11 hours and still need a nudge to get out of bed. In fact, as a young adult, (co-author) Julie Wright’s son can still sleep 10 hours at night. If they’re allowed to

sleep to their body’s full desire, many kids will sleep even more at age 16 than they did at age 10.

If this sounds surprising, consider how much sense it makes. As we have learned, the brain and body are going through massive changes during adolescence, and much of this transformation in the brain happens during sleep.

Remember when you worked so hard to get your baby sleeping on a schedule, or you noticed your toddler became hyper and overtired, so you created an elaborate bedtime routine to help him wind down? We take such good care of our little ones’ sleep because we know their brains are exploding with growth. Teenagehood is the same. Changes related to puberty and a reorganisation of the brain mean that the period of adolescence, similar to earlier massive developmental explosions, is a time when sleep becomes more important, not less. Meanwhile, recent estimates put the average teen at a loss of about two hours of sleep every school night.

Now we understand the remarkable

abilities teens have to sleep when given the chance. But despite this huge biological thirst for sleep, teens do tend to naturally stay up later than their younger siblings and often their parents.

The average bedtime as kids move through middle and high school goes from 9pm to 11pm or midnight, and some stay up much later than that.

This late-night tendency is due to a shift in the teen sleep clock. The master clock synchronises the multiple clocks in other tissues throughout the body. Clocks in the digestive system know that we eat around a certain time, so our tummy begins to grumble, and clocks in our neurological system know when we’ll need energy and when we’ll need to wind down. These clocks affect when we are tired, alert, creative, and hungry, as well as our body temperature, metabolism, and other physiological processes.

When the brain’s clock knows that night is coming, the hormone melatonin is released, signalling the time for sleep is approaching, allowing us to wind down, become drowsy, and let sleep take over.

Toward biological morning, the brain sends signals to tell us, “It’s day!” Melatonin levels go down and cortisol and other activating hormones rise. We become alert, productive, and ready to enjoy the day.

Little kids’ circadian rhythms, otherwise known as their internal clocks, tell them to go to bed early and wake up early. Most little kids can fall asleep at 8pm and be awake and ready to play around 6am.

As kids enter adolescence, though, they experience a natural shift to a later biological timing. This is not just a preference; it happens at a chemical level.

Studies measuring the melatonin levels of adolescents have found that these rise about two hours later than younger kids’ (pushing natural bedtime and natural wake time two hours later as well).

This phenomenon of shifting to a later rhythm is called a “sleep phase delay”.

The sleep phase delay has been linked to the onset of puberty, suggesting that something in the neurological and chemical changes related to puberty triggers the delay in the master clock. The brain becomes paced differently, and from a chemical standpoint, the biological night of an adolescent is shifted later.

This is key to understanding how to support teenagers’ sleep: the brain tells them to go to bed later and wake up later than young kids and grown-ups.

From a chemical standpoint (and given all that is on their plate), most are unable to fall asleep early enough to regularly get eight to 10 hours of nightly sleep. High schools that start at 7.45am or even 8am go hand-in-hand with sleep deprivation.

This sleep phase delay means that an eight year old might be drowsy and ready to sleep by 8pm, but an adolescent is physically unable to fall asleep for the night until about 10pm or later.

This delayed timing also means that teens are not physiologically ready to wake up until later than the eight year old.

As all parents know, little kids are prone to early rising, ready to build Lego and do cartwheels at 6am or earlier. In fact, the younger the child, the earlier they tend to start the day.

But as kids reach adolescence, what was once gymnastics hour is now still the biological night. In fact the early morning hours for adolescents contain intense and valuable stages of sleep, including dreams – making this important sleep time. This explains why

a fire engine could drive through the bedroom and a teen could keep sleeping peacefully: 6am is still the night, according to a teenager’s sleep clock.

Our preference for morning or evening is called our “chronotype”, or you might hear people describe it as being an early bird or night owl.

If they’re allowed to sleep to their body’s full desire, many kids will sleep even more at age 16 than they did at age 10

Most adolescents shift into night owls, in

a clear way. Parents of these teens and the teens themselves tell us it’s very hard to imagine falling asleep before 11pm and it’s very hard to wake up in the morning.

A smaller subset seems to keep a morning tendency – such as our friend’s 16 year old who can fall asleep at 10pm and wake early and easily for school.

These teens tend to grow into adults who likewise prefer early schedules.

For most teens, the evening preference begins around age 12 and reaches its peak for girls at age 19.5, and for boys at age 21.

In our 20s, we tip back toward a morning preference again. This is a phenomenon that has been observed across cultures around the world.

In fact, researchers have also measured a sleep phase delay in other mammals that coincides with sexual maturation, which backs up the biological nature of the teen sleep delay. Rhesus monkeys, marmosets and mice, for example, experience a delay in their internal clock around the time of puberty.

So then, gaming and video chatting with

friends past midnight is just natural? Should we let teens do this if it’s what their brain clock dictates? Not so fast.

The sleep phase delay naturally shifts teenagers’ sleep somewhat later, but light, technology, school and social forces prey on this natural delay, adding an additional delay and pushing sleep times to an unnatural and often unhealthy point.

The environment takes advantage of and accentuates the sleep phase delay and keeps teenagers awake way beyond a natural bedtime.

To allow our paleo-sleep to emerge, we have to put down the VR headset and step away from the phone.

Generally speaking, light exposure in the evening will convince the brain it’s still day and will delay drowsiness. Light suppresses the release of sleep-inducing chemicals like melatonin.

Remember, over hundreds of thousands of years, our eyes and brains evolved to respond to sunlight as an indicator that it’s daytime and we should be alert, but now computer screens, phones, and even interior home lights can send the same signals. All these sources of light, along with the mental stimulation of social media, games, video chats with friends, and so forth can increase arousal and suppress sleep chemistry.

To make matters worse, research has pointed to adolescents being more sensitive to evening light and therefore prone to an accentuated delay in falling asleep.

To a large degree, this explains why teen sleep has declined alarmingly in recent years, as we have ever more sources of light and diversion from our homes and devices.

On the other hand, sunlight in the morning causes an

“advance” and sets the circadian rhythms earlier, putting us on an earlier schedule and making us sleepy earlier in the evening.

These “delaying” and “advancing” effects are a really important takeaway for adolescents and parents.

Teenagers need less light in the evening and

more light (sunlight is the absolute best) in the morning, to keep their brain clocks in sync. Otherwise the sleep phase delay becomes a runaway train.

Morning sunlight keeps the train on the tracks, constantly nudging and sending alerting “go” signals to internal clocks to keep them more in sync with the schedules imposed by school, and to somewhat counteract the tendency to become delayed. It’s amazing that morning sunlight starts a timer in the brain that sets the stage for the sleep that will come 15 or so hours later; but it’s true, morning sun makes it easier to fall asleep at bedtime.

The cells in our eyes that set the circadian rhythms respond best to the sun, so turning on the lights in your house does not have as strong an effect.

When your teen wakes, she should spend a short amount of time outside. In sunny climates, five to 10 minutes of outdoor sun in the morning may suffice.

In other areas, more time may be needed to have the same effect, although the sun through clouds is still stronger > than interior home lights.

A good rule of thumb for teens is to go outside for breakfast, walk to school if possible, spend first period outside (hint to schools), and sit outside or go for a walk or a run before 10am on the weekends.

After morning has passed, the circadian rhythms have moved on and light will no longer advance the clock. If a teen’s normal wake-up time is 7am, then the internal clock will respond to morning sun for a couple of hours after this, but going outside at noon is unlikely to help.

In the evening, lowering the lights in the home, turning off computers, and putting away phones is key to allowing a natural rise in melatonin, which invites the body to fall asleep easily.

This is an edited extract from Generation Sleepless: why tweens and teens aren’t sleeping enough, and how we can help them by Heather Turgeon and Julie Wright, Scribe by $33