“If you want to fall asleep at night, then you need to go outside in the morning and get bright light.”

Have another read of that comment above - does it make sense? Because it shouldn’t.

Yet, it is scientifically true!

Our circadian rhythms (aka, body clock, biorhythms, biological clock) can be manipulated by the shining of bright light into our eyes.

So I often say to teenagers, that besides the ‘graphics’ and ‘frame rate’ being better outside - the light is healthy for their sleep.

For teens diagnosed with Delayed Sleep-Wake Phase Disorder (DSWPD) - an extreme version of a circadian rhythm that has delayed so much that it’s affecting their life - exposing their eyes to bright light in the morning can help them fall asleep quicker.

We’ve scientifically demonstrated this with a couple of the biggest studies in the world (Gradisar et al., 2011; Richardson et al., 2018).

But because we know it works - doesn’t mean it automatically works.

First of all, you’ve got to convince the teenager that getting light in the morning will help them sleep better.

Because right now - that connection makes no sense!

Lesson 2.1 - Light’s Effect On Our Body Clock

There’s a reason it’s called a body clock.

Our bodies have evolved to wake up when the sun rises, and our visual system has evolved such that light helps to keep the timing of our sleep consistent.

Just like our ears have two purposes (hearing and balance), so too does our visual system.

Our eyes’ two purposes are to see the world around us - and to keep our body clock timing consistent.

How?

When light hits our eyes, these ‘light signals’ travel from the back of our eyes, and down the optic nerve. The optic nerve sends visual information to the back of our brain so we can see our world.

But on the way to the back of the brain, the optic nerve passes close to where the body clock resides. Right in the centre of our brain.

What I tell teenagers is that when we open our eyes in the morning and ‘see the light’ - it’s like pressing the Start button on a stopwatch.

It’s a way to tell our body clock that we’re starting the day now.

Lesson 2.2. - How Do We Know It Works?

In 2011, we published the first comprehensive clinical sleep trial to improve teenagers’ sleep (specifically, their delayed circadian rhythms; Gradisar et al., 2011).

As I mentioned in last week’s blog, I learned how to do this treatment when I worked in an Adult Insomnia Clinic. It was using Bright Light Therapy (BLT) to improve their circadian rhythm timing - and Cognitive-Behaviour Therapy for Insomnia (CBT-I) to improve any associated insomnia.

The teens who received our CBT + BLT treatment:

• fell asleep faster

• fell asleep earlier

• got more sleep on school nights

• experienced improved daytime feelings, like less sleepiness and fatigue.

• and 6 months later, these sleep benefits were still present. At this 6-month follow-up they were also showing less depression symptoms.

A few years later, Cele Richardson started her PhD with me and set out to see what happens when you just give BLT to teens (my mouth is drooling every time I write ‘BLT’ at the moment - which is odd considering I’ve been trialling a pescatarian diet for several months now…)

By the end of her PhD - ‘Dr’ Cele Richardson found that BLT:

• helped teens fall asleep faster (Richardson et al., 2018)

• meant teens fell asleep earlier (Richardson et al., 2018)

• provided more sleep on school nights (Richardson et al., 2018)

• improved their cognitive performance (eg, how fast they process info; Richardson et al., 2018)

• reduced their depression symptoms (Richardson & Gradisar, 2021)

• and decreased an array of associated insomnia symptoms (eg, rumination and worry, attentional bias towards sleep-related threats, their misperception of their sleep, etc.; Richardson et al., 2019)

In between our studies, there were other studies published in Norway showing BLT (and melatonin) improved the sleep and daytime performance of young people with a delayed circadian rhythm (Saxvig et al., 2014; Wilhelmsen-Langeland et al., 2013).

Of all techniques to help teenagers sleep better - bright light therapy … (nope, I’m still salivating) …. has the most scientific evidence to support its use.

Lesson 2.3 - Tell Me About This Thing You Call ‘Light’

In our first clinical trial, we offered teenagers the choice of getting natural light outside, or sit in front of a bright light lamp.

The light lamp is handy when the weather outside is unpleasant (windy, rainy, etc.), or the sun has not yet risen.

The other thing about the light lamp was that it was providing white light.

As mentioned in last week’s blog, my PhD supervisors had discovered that short wavelength light - which we perceive as light that is coloured green or blue - was the most effective light at changing our circadian rhythm timing.

Their studies (Wright et al., 2004) led to the development of green LED light glasses - known as Re-Timers.

In her PhD, Cele tested the Re-Timers with teenagers. But she added a twist.

• Half of the teenagers got the standard green light Re-Timers.

• The other half of the teenagers got a pair of red light glasses.

My PhD supervisors found that long wavelength light - that we perceive as red light - was not effective at changing the timing of the circadian rhythm.

However, Cele found that no matter whether the teens wore green or red glasses, their sleep improved.

That’s right - red LED glasses worked.

And she wasn’t the only one. Remember those Norwegian studies I mentioned? They too found that red light had a therapeutic effect (Saxvig et al., 2014; Wilhelmsen-Langeland et al., 2013).

Conclusion?

If you trust me - but more importantly trust what I write in these blogs - I implore you to hear me out. Because I want you to push through to the end of this blog and understand the rewards of bright light therapy for teens.

First, if you’ve got this far and wish to know more about BLT, I encourage you to become a subscriber to our free weekly newsletter.

Because in a couple of day’s we’re gonna send out this blog - but add an extra bit of info at the end about bright light therapy.

And it’s such an important piece of information, because we hear so many GPs (and social media posts) get it wrong.

And if you get this wrong - you actually make a teenager’s sleep worse.

It’s about the precise timing of bright light therapy.

If you were too late to subscribe, I can only encourage you to subscribe right now at the bottom of this blog so you don’t miss out on all these ‘sleep nuggets’ that our subscribers get.

And if you wish to step into a Delorean and travel back in time - that is, begin learning some of the step-by-step techniques to do bright light therapy (ie, how to do it) - then you can become a WINK Member (learn more here at the JOIN tab).

If you do join, I’ll get you into our Member discussion forums where you can learn a lot from the Members - and me - about treating circadian rhythm delays (we’re actually discussing a case of an adult at the moment). And I encourage you to go to our recorded August Live Q&A to watch me teach one of our Members the step-by-step processes of how to do BLT).

I know for a fact that anyone working to help others with their sleep are limited in their skills because they don’t know the ins-and-outs of circadian rhythms and how to do BLT.

And I know that when they learn it - they are way more confident - and more effective at helping others sleep.

I know this because I teach it every week. And I’m helping teens every week.

Teens are a great bunch to work with.

It is so wonderful when you see the results of BLT - when you see the teens ‘come alive’ (right now I’m thinking of the teen I saw on Wednesday) - and even joking around and having fun with their parents … again.

THAT is the true reward…

• Prof MG