Sun & Light Series: Part I - How Light Dictates The Way Our Bodies Function
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).
- Part I - How Light Dictates The Way Our Bodies Function
- Part II - Artificial Lights Are Destroying Our Eyes, Skin and Health
#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.
- 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
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
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).
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.
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.
Photoreceptors In Our Skin & Eyes
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.
- 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.
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)
The light wavelengths present in a sunset ⬇️:
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)
“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.
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.
- 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.
Solutions
- >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