This article may contain some of the most important information that you need in order to keep your sleep and overall health in check.
There is a great force at play in our lives that provides us and every organism on earth with energy, light and heat.
What am I talking about?
Walk outside, take your sunglasses off and look up – this miracle is the sun.
Seeing as we humans are essentially solar-powered creations, it’s time for a greater understanding of the role that the sun, and specifically the light that it provides, plays in a good night’s kip..
Light is known as our master ‘zeitgeber’ (this is a German word that translates as ‘time giver’).
Zeitgebers are environmental cues that control our body’s sleep & wake cycle (also known as our circadian rhythm).
While there are several environmental cues that impact our daily rhythms, light has by far the greatest influence on our sleep quality and quantity over anything else.
You could quite literally say that light ‘sets our clock’ with regard to the circadian processes that occur every day in our body over a roughly 24-hour period (of which sleep is one).
In order to keep our body and mind healthy, we must operate under rules governed by nature that allow us to synchronise or match our internal 24-hour clock to that of the earth.
This process begins every morning with the rising of the sun – or, at least, it should.
“Mastering your sleep begins with mastering your light exposure.”
For millions of years, our ancestor’s sleep-wake cycle was chiefly orchestrated by exposure to light from the morning sun.
When we come into contact with morning sunlight, the cue received by our eyes sends a signal cascade to our brain that brings energy, alertness and vitality. It plays a key role in the production of vital brain chemicals such as serotonin, dopamine and endorphins, which regulate our mood, attention and alertness.
This quite literally affects every single system of our body, as natural morning light signals the beginning of our daily cycles.
Therefore, it’s crucial that we get out and about in the daylight as soon as possible after waking up each morning to help synchronise our natural rhythms.
The magic amount of time is suggested to be 15 minutes. Just being outdoors is effective, even if it’s overcast there is still much greater light intensity than inside.
We wouldn’t expect our watches to work correctly if we never set them to the right time or ensured that they contained a source of power. This is somewhat similar for our body & mind. Our system requires the environmental zeitgeber or signal of light and the energy that this process provides to start doing what it needs to do for the day head.
Sadly, these days, many of us avoid the sun like the plague.
We wake up in darkened houses, eat breakfast in light-deprived kitchens, jump in our blacked-out cars and head to our dimly lit workplaces.
If our bodies don’t receive this vital signal provided by natural light, the chances are that we will spend our days feeling fatigued, moody, unmotivated and at worse – unable to get to sleep easily each night as our internal body clock is confused and unable to identify at which time it should begin to produce melatonin, our key sleep hormone, later that evening.
“Exposing yourself to morning sunlight literally turns on a timer in your brain that says ‘okay, now it’s time to wake up, but 14 hours from now it is going to be time to sleep’. We must begin to see AM light as not only a morning energiser, but also the necessary groundwork for deep, refreshing sleep in the evening.”
As the sun disappears each evening, this is the next cue (or zeitgeber) from our environment that directs our body to produce our key sleep hormone; melatonin, produced by our body’s pineal gland.
When the sun goes down and the light intensity in our environment decreases, our pineal gland ‘turns on’ and the production of melatonin begins.
This causes us to feel relaxed and prepares us to move toward a state of sleep.
Almost all of our ancestor’s daily tasks of survival (hunting, fishing, gathering) took place during the daytime as these activities were directly supported by light from the sun.
It is only since the invention of constant electricity that we have been able to light our homes artificially every single evening.
When we expose ourselves to artificial light after the sun has set, the signal that we are sending to our evolutionary genes (which govern our health) is that it is still day time.
This tricks our circadian biology into believing that it is still time to go fishing, which has extremely detrimental impacts to our sleep and overall health.
To our still primitive brains, the assumed presence of daylight means that there are potential threats out there in our environment, which causes our brain to (understandably) halt the process by which we get tired and fall asleep so that we are at a reduced risk of becoming somebody’s lunch.
These days it is not just bright light bulbs, but also laptops, computers, games consoles, mobile phones, televisions, iPad, tablets and a range of other devices that bombard us with bright artificial light that locks us into direct battle with our evolutionary sleep principles.
Exposing ourselves to this artificial man-made light reduces our ability to produce enough melatonin – our key sleep and anti-ageing hormone.
Without enough melatonin, we don’t fall asleep as quickly and easily as we could, and our sleep quality is much poorer.
Any exposure to blue light and green light frequencies (the main components of modern screens and LED light) prevents our brain from calming down, producing melatonin and getting a good night’s kip.
One study invited participants to spend two five-day periods sleeping in a tightly controlled laboratory environment.
The first five-day period was spent reading on an LED-lit iPad for 2 hours before bed, then, after a period back at home, the group was invited back into the lab to read a paperback book for 2 hours before bed for 5 nights.
During each 5-day period, the first reading the iPad and later the paperback book, researchers recorded various aspects of the participants’ sleep including the timing of melatonin production and the amount produced.
The results were astounding. Reading on the LED-lit iPad for 2 hours before bed each night affected their melatonin production in three main ways.
All of these sacrifices for our precious sleep to read an iPad for 2 hours before bed!
I would like to make it clear that I am not anti-technology.
I am sat here at this very moment writing this paragraph using my laptop whilst I regularly check my work emails on my mobile phone at the same time as listening to music via my iPad.
Electronic devices are not the devil. But I hope by now you can understand that we need to take control over the time of day at which we are exposed to these devices and the lights that they emit if we want to sleep peacefully and live to our fullest potential.
We humans are solar-powered creatures.
Light is the master of our circadian biology, and therefore the master of our sleep.
As our circadian biology rules our overall health, many would make the argument that light is as important for our health as food.
Try making some of the simple changes that we have suggested and observe the impact that this has on your mood, energy, performance and every other aspect of your life.
As always, I have a few questions…
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