We’ve all been there…
Ripped from the clutches of sleep by your alarm clock. Dragging yourself out of bed. Struggling through the workday, punctuated with regular caffeine doses in the hope that this one will finally kick your brain into gear. And yet, when you finally settle into bed at night, you’re unable to drift off into the wonderful slumber your body so desperately craves. And thus, the cycle from hell repeats itself.
If you’ve ever experienced this phenomenon then you’re not alone. Russell Foster, a neuroscientist specialising in sleep, claims that over the past 7 decades the average time spent asleep per night has dropped from the recommended 8 hours to only 6.5 hours. Why are so many of us struggling to fall asleep at night? Is it because you’re thinking too much? Is it the stress of modern lifestyles? Or is there something deeper at play here?
The circadian rhythm and sleep
The circadian rhythm, also known as our body clock, refers to the approximately 24-hour rhythm by which we operate. It regulates things such as our appetite, our core body temperate, and crucially our wakefulness and sleep. Controlled predominantly by the hormones, cortisol and melatonin, our circadian rhythm continues ticking throughout our lives.
Light and the circadian rhythm
Although our circadian rhythm is endogenous (internal), it is set by external cues known as zeitgebers (German for timekeeper). Our brain evolved to use environmental cues to synchronise our body clock with the sun’s day-night cycle. The most reliable cue, and therefore human’s primary zeitgeber is light.
Receptors in the bottom third of the eye called intrinsically photosensitive retinal ganglion cells (I dare you to try say that after a couple of beers), detect the light of the blue sky and send signals to the brain to let it know it is day time stopping the uptake of melatonin.
Once upon a time, humans woke with the rising of the sun and slept shortly after it set. We began to augment this rhythm with the introduction of fire and later candles. However, they weren’t without their issues. They smoked, they had to be tended to regularly and posed a constant risk of fire. Because of this, in many medieval cities, residents were required to extinguish their cooking fires (the only interior lighting most could afford) after dinner. Curfew comes from the Old French couvre-feu, meaning cover fire. Gas lanterns, found on the streets of London as early as 1816, began to change this. However, it was the invention of the electric lightbulb that enabled a decoupling from the sun, the effects of which touch almost every aspect of modern culture, from the way we work to the way we design our buildings.
Most of us take light for granted, because for our entire lives it has been just a literal flick-of-a-switch away. If you doubt the profound ways which artificial light impacts our lives, think back to the last time there was a power cut. I remember in the wake of one of the Christchurch Earthquakes we lost power. After lighting a few candles, I discovered that there isn’t an awful lot to do when it’s dark and decided to go to bed early. However, for all the development artificial light has catalysed, it has had some unexpected side effects, the extent of which is now beginning to be uncovered.
Research suggests that artificial light and especially LED lighting, which is commonplace in offices, may be disrupting our circadian rhythm and potentially jeopardising our sleep.
Light, which was once our biology’s most reliable reference to the time of day, has now been homogenised, leaving our circadian rhythms in a state of utter confusion.
How does artificial light differ from sunlight? I’m glad you asked. As you may be aware, white light isn’t merely white, but rather it contains a range of colours spanning the visible spectrum. If you’re confused, take a look at Pink Floyd’s Dark Side of the Moon album cover and you’ll know what I’m talking about.
Below is a spectral graph (a graph that illustrates which colours (or wavelengths) are of the greatest intensity), comparing sunlight to the 4000K LEDs which are found in most offices.
Remember those intrinsically photosensitive retinal ganglion cells? As you can see, sunlight is rich in the light these cells are most sensitive to (labelled by the blue light we need), while the LEDs which light most modern offices have a trough in the spectrum. Current LEDs fail to give us the light we need to set our circadian rhythm, leaving your circadian rhythm confused as to whether it is time to stop sleeping and promote wakefulness. When you consider that in industrialised nations such as the USA, Canada, and Britain, it is suggested that on average people spend more than 90% of time indoors, it becomes apparent why this could be a health risk.
To add insult to injury, consider your final minutes before bed last night. Did you stand under the bright glare of your bathroom lights while brushing your teeth? Did you go on your phone in bed? Are you reading this on your phone in bed right now? While LEDs don’t provide enough of the blue light we need during the day, they provide too much at night. A recent study found that reading on an iPad for 30 minutes before bed rather than a book will delay the onset of deep sleep by 30 minutes, (https://www.sciencedirect.com/science/article/abs/pii/S1389945716000599).
The blue light of the backlit screen tricks our brain into thinking the sun hasn’t set yet and delays the production of melatonin, causing us to feel alert.
While natural light provides our body with a clear contrast between day and night, artificial light gives us an apathetic midpoint which fails to give us what we need during the day, while giving us too much of what we don’t need at night.
I’m not suggesting that artificial light may be the only reason why you can’t sleep, or that it is the sole reason why people may be sleeping less than they once did. However, it is a key factor that is often overlooked. Whether it’s working late to meet a deadline, or staying up late binge-watching your favourite series, it is hard to deny the advent of artificial light catalysed these behaviours.
Maybe instead of asking “why can’t I sleep?”, we should be asking “how can I sleep?”
Despite its downsides, ditching artificial light is not possible or even desirable. Instead, I propose that we need to design our lighting and spaces in a way that better meets our circadian needs. This is the challenge we are dedicated to overcoming at OSIN.
While a modern lifestyle can make it difficult to maintain a natural circadian rhythm, there are some practises you can adopt right now which will go a long way to helping the length and quality of your sleep:
⁃ Reduce blue light at night by using OSIN for Home. Engineered to provide warm and comfortable night time light, the OSIN Bedtime Bulb uses spectrally optimised LessBlue™ Technology to eliminate sleep-disturbing blue and green light at night
⁃ Switch off electronic devices one hour before bed. If you must use them, dim the brightness and switch on night mode as this helps decrease the amount of blue light.
⁃ Keep your bedroom cool. While light is our primary zeitgeber, temperature is also a way of letting our body know that the sun has set, and it is time to sleep.
⁃ Ensure that when you go to sleep, your bedroom is as dark as possible. Close curtains so that no light pollution creeps its way in.
⁃ Go to bed and wake up at the same time every day. Sleep is not a location you can suddenly arrive at, but instead, it is a stage in a larger biological process. Therefore, dramatically shifting the time you wake up and go to sleep will leave you feeling jet lagged. We are all familiar with setting an alarm to wake up, but I suggest setting an alarm reminding you to go to bed at night. By maintaining a regular wake and sleep time it will better allow your body clock to achieve a natural rhythm.
While these steps aren’t a complete solution, they can go a long way in helping you get a good night sleep. Ultimately, I’m optimistic that human centric lighting will provide us with a brighter future (pun totally intended).