Sun & Light Series: Part I - How Light Dictates The Way Our Bodies Function

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Disclaimer: Not medical advice. The following information is for educational purposes only.

Welcome to the Sun & Light Series. This is a series of educational articles, dedicated to unravelling how the light sources we live under and surround ourselves with, ultimately influences the way our bodies function (or malfunction).

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Why should the average person care?

#1 - Your eyes and skin: most people are unaware that their modern lifestyles are causing damage to their skin and eyes daily. Myopia, eye diseases, skin cancer, etc are on the rise globally. #2 - Your hormones and bodily functions: Hormones and bodily functions are switched on/off depending on our light environment. Get your light hygiene wrong and your mood, energy, and bodily functions suffer.

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In Part 1, Our Goal Is To:

Understand the basics of how light works
Understand which types of lights are stressors, and which are regenerative
Learn how the sensors in our skin & eyes interpret light into signals, which then influence how our bodies work

Introduction

Our biology is deeply intertwined with light. For millions of years, we’ve evolved under the sun and cycles of day (light) and night (dark).

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Sleep-Wake Cycle Hormones:

Cortisol: When bright light (sun) in the morning enters our eyes, our body releases the cortisol hormone which reduces sleepiness and wakes us up. Melatonin: At night, when darkness sets in, our body releases melatonin (sleep hormone) which makes us feel sleepy, preparing us for bed. These two hormones are deeply influenced by light, and they’re not the only ones.

Cortisol & Melatonin: The Hormones That Regulate Our Body Clock

Cortisol acts as a natural stimulant in the morning to reduce sleepiness and wake us up. Melatonin is the sleep hormone that releases at night to make us feel sleepy and fall asleep.

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Cortisol & Melatonin: The Hormones That Regulate Our Body Clock

Beyond regulating our sleep-wake cycles, many other processes within us are shaped by the different type of lights we’re exposed to:

Hormones
Metabolism (process of converting food into energy)
Skin health
Eye health
Mood
And more…

The Light Spectrum

Pay attention to the image below. This is the foundation of how light works. It’ll be repeated throughout this article whenever relevant. Each colour represents a different light wavelength. Each of these are responsible for switching on/off different processes within our bodies.

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All light sources, whether from the sun, LED light bulbs, electronic screens (TV/laptop/mobile phone/tablets), flashlights, etc all contain spectrums of light.

Photoreceptors In Our Skin & Eyes

Credits: Dr Max Gulhane

Our skin and eyes have sensors in them called photoreceptors. (LINK 1, LINK 2) These sensors detect different light wavelengths and convert them into signals for our brain and body to process → leading to various physiological functions.

Credits: allaboutvision.com

Longer wavelengths (red and infrared) can penetrate deeper into the skin and body, going as far as tissues, muscles, nerves and even bone.
Shorter wavelengths (UV and blue) can only penetrate the upper layers of the skin.

Credits: grassrootshealth.net

The sun contains the full light spectrum (every single color)

Examples Of Physiological Functions, When Our Skin & Eyes Detect Light:

When UV-B is present: Vitamin D production (LINK)
When UV-A & UV-B are present: Melanin production (a tan) (LINK)
When UV-A is present: Cardiovascular benefits - lowering of blood pressure & increased blood flow(LINK)
When Blue Light is present: Increased alertness & suppression of melatonin (sleep hormone) (LINK)
When Red Light is present: Skin rejuvenation and collagen production (LINK)
When Infrared Light is present: Deep tissue repair, inflammation reduction, more energy to power our cells (LINK)

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Our eyes can't see UV light and Infrared light. The photoreceptors in our skin and eyes do detect them.

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Below is a spectrometer device. It measures the type of light wavelengths present in any environment (sunlight, indoor lights, computer screens, fire, anything that is a source of light).

The light wavelengths present in a sunset ⬇️:

Credits: @Bluelightdiet

Stressor Wavelengths:

The colors to the left (UV to blue lights) are considered stressor wavelengths. They provide benefits for us, however too much stressor wavelengths can damage our health (sunburn, aging & wrinkling skin, eye damage, sleep disruption, etc).

UV-B Pros 👍: Stimulates the production of Vitamin D (LINK) Cons 👎: Excessive amounts can cause sunburns (LINK)

UV-A Pros 👍: Cardiovascular benefits → lowers blood pressure and improves blood flow via production of Nitric Oxide (LINK) Cons 👎: Excessive amounts can cause skin aging and wrinkling (LINK)

Blue Light Pros 👍: Tells our brain it’s daytime → boosts alertness, memory, cognitive function and elevates mood (LINK). Also known to effectively treat acne (when paired with red light) (LINK) Cons 👎: Known to damage skin and eyes. Disrupts our metabolism and contributes to mental disorders. (LINK 1, LINK 2, LINK 3, LINK 4)

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ALAN = Artificial Light At Night

“This study is the first population-level study that confirms the results of laboratory research and cohort studies in which ALAN was found to be a contributing factor to excessive body mass in humans.”

Link to study: https://www.nature.com/articles/ijo2015255

Regenerative Wavelengths:

The colors to the right (Red and Infrared (IR)) wavelengths are considered regenerative wavelengths.

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Since the 1960’s, there have been thousands of peer-reviewed studies on the benefits of red and IR light (LINK)

Red Light Red light is primarily known for healing and rejuvenating the skin - (LINK)

Stimulates collagen production, improving skin hydration and elasticity
Reduces wrinkles
Helps wounds and scars heal faster

Infrared Light Infrared (IR) light is primarily known for penetrating deeper into the skin, promoting healing, pain relief, tissue repair and more - (LINK)

Improves blood circulation
Reduces inflammation
Supports deep tissue repair
Stimulates the production of ATP (boosts energy production in our cells, making them more efficient)

Here's the spectrometer readings of natural sunlight vs artificial light:

You can see that natural sunlight has all the regenerative wavelengths, to balance out the stressor wavelengths.
The incandescent light bulb has more regenerative wavelengths and almost no stressor wavelengths.
LED and fluorescent lights have very sharp spikes in blue wavelengths - which is what's damaging to our eyes, skin and health. They also have very little regenerative wavelengths to balance out the stressor blue lights.

An Example of Light Damaging Skin

This is Bill McElligott, a sixty-nine-year-old delivery truck driver. For 28 years, the left side of his face was exposed to the sun, filtered through the truck’s glass window. "Sideways, he looks like two different people.” - Dr. Jennifer R.S. Gordon, the doctor who treated the patient Original study: Unilateral Dermatoheliosis - New England Journal of Medicine More on his story: Truck driver shows extreme sun damage on one side of face Dermatologists concluded that the sun caused this, due to the fact that UV-A mostly passes through glass. They’ve missed some important points, which we’ll look at below.

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The lights that pass through glass can differ, depending on how it’s designed. The below image is a typical guideline for how most glass alters light.

All UV-B is blocked → no sun burning, no vitamin D production or melanin (tan)
~75% of UV-A passes through → most of the stressors in UV-A that age and wrinkle skin are present
100% of blue light passes through → 100% of skin damaging wavelengths present.
Only ~50% of regenerative wavelengths are coming through.

To summarize, he’s getting:

Most of the stressor wavelengths on the left side of his face
Only half of the regenerative wavelengths

He’s accumulating more stress to his skin than regeneration. Now compound this for 28 years straight. Here’s a video by Blue Light Diet measuring the light profile of glass using a spectrometer. This verifies how light coming through windows is altered, leaving most stressor lights coming through, and reducing significant amounts of regenerative lights.

So is the sun really the root cause? Nope. It’s the glass that’s altered the light. Here’s the spectrometer readings of natural lights ⬇️:

Natural sunlight ALWAYS delivers stressor wavelengths with regenerative wavelengths to balance out.
Every blue light is balanced with red light. Every UV light is balanced with IR light.

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Around sunrise and sunset (evening image) there's almost zero stressor wavelengths. There is however a very high ratio of regenerative wavelengths. These times are ideal for skin repair & rejuvenation. If Bill had regularly gotten exposure to sunlight during sunrise/sunset, this would've repaired and reversed any skin damage from the altered light profile.

Solutions

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Getting sunlight through glass regularly is not healthy. There’s a much higher ratio of stressor wavelengths compared to regenerative wavelengths. So what can you do? Don’t stress. It took 28 years for the truck driver to accumulate that damage. There’s no need to become fearful of sunlight through glass for short periods. If you’re chronically being exposed to altered light like the truck driver daily, across many years, and NOT getting regenerative wavelengths, that’s when the damage compounds. Just make sure you’re regularly getting higher ratios of regenerative wavelengths to offset any skin damage. Best ways to achieve this:

>10 mins of sun exposure within ~1 to 2 hours of sunrise
>10 mins of sun exposure within ~1 to 2 hours of sunset
Red light therapy devices (make sure it’s flicker-free, and low EMF)

Additional things you can do:

Wind down your windows
Tint your windows (choose tints that block out UV-A and blue lights if possible)
Minimize time spent getting sunlight through windows

Wrapping Up

Now that we’ve learned the fundamentals of light and how it influences our physiology, we’re ready to move onto Part II. In Part II of the Sun & Light Series, we’ll be looking at how the artificial lights in our modern lives are destroying our eyes, skin, and health on a daily basis. Click below for Part II - Artificial Lights Are Destroying Our Eyes, Skin and Health

Sun & Light Series: Part II - Artificial Lights Are Destroying Our Eyes, Skin and Health

Artificial lights are all around us; the lights in our homes, our phones, TV, laptop, tablets, shopping malls, street lights, etc. These lights contain excessive levels of blue lights which destroy the integrity of our skin, eyes, hormonal health and more.

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Sun & Light Series: Part II - Artificial Lights Are Destroying Our Eyes, Skin and Health

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Sun & Light Series: Part II - Artificial Lights Are Destroying Our Eyes, Skin and Health

Sun & Light Series: Part III - How to Use the Sun the Right Way

Cortisol & Melatonin: The Hormones That Regulate Our Body Clock

Blue Light: The Enemy of Good Sleep

Sun & Light Series: Part I - How Light Dictates The Way Our Bodies Function

On this page

Sun & Light Series: Part I - How Light Dictates The Way Our Bodies Function
Table of Contents
Introduction
The Light Spectrum
Photoreceptors In Our Skin & Eyes
Stressor Wavelengths:
Regenerative Wavelengths:
An Example of Light Damaging Skin
Solutions
Wrapping Up
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