- Lucy Bassett
- Dec 22, 2025
- 4 min read
As we move just beyond the shortest day of the year, many people are still feeling the effects of the long, dark stretch of winter—mood dipping, energy waning, and sleep feeling just a little more fragile. It’s no coincidence. Human beings are designed—biologically, ancestrally, and energetically—to live in partnership with natural light. Long before modern life, our ancestors rose with the sun, spent their days outdoors, and wound down with the sunset. Our bodies still carry that ancient design, no matter how modern our world has become.
Today, most of us spend our lives enveloped in artificial light: overhead LEDs at work, bright screens at night, and very little meaningful time outdoors. What most people don’t realise is that light is not just something we “see”—it is a nutritional input, a biological signal that instructs our mitochondria, hormones, mood, metabolism, immune system, and even longevity.
Drawing on insights from The Mitochondriac Manifesto by Randy Lee, along with ancestral wisdom and modern science, let’s explore why light might be one of the most important (and overlooked) keys to health and healing.
Light as a Biological Language
Randy Lee explains beautifully that light is not passive. Light speaks to our biology. Our mitochondria—the tiny energy-generators inside our cells—are exquisitely sensitive to different wavelengths of light. These light signals help regulate:
Energy production
Hormones such as cortisol and melatonin
The circadian rhythm
Cell repair and autophagy
Mood and neurotransmitter balance
When we step outside in the morning, even for just a few minutes, natural light hits receptors in our eyes and on our skin. This signals the brain that it’s daytime and triggers a cascade of biological processes: cortisol rises appropriately, metabolism increases, serotonin is produced, and melatonin production is set for the evening.
Artificial indoor lighting simply cannot replicate this. Its spectrum is incomplete and often heavy in blue light—especially at the wrong times of day.
The Problem With Artificial Light
Artificial light isn’t only not enough—it can actively interfere with our biology.
Too much blue light in the evening stops melatonin production and disrupts sleep.
Lack of full-spectrum daylight keeps our circadian rhythm confused.
Indoor environments deprive the skin and eyes of the wavelengths that support mitochondrial function.
When we talk about energy, mood, burnout, anxiety, poor sleep, and even gut imbalance, we often overlook light as a contributor. But our bodies are still wired for the ancestral pattern: sunlight by day, darkness by night.
Just like we need nutrient-dense foods, whole fats, fermented foods, and ancestral preparation methods (as many of our GAPS principles teach), we also need ancestral light.
Melanin: The Molecule That Listens to Light
Randy Lee describes melanin not just as a pigment, but as an extraordinary molecule that interacts with light in profound ways. Melanin absorbs and transforms light—it is one of the ways the body converts light into usable biological energy.
Melanin is involved in:
Protecting cells from oxidative stress
Supporting mitochondrial efficiency
Regulating circadian rhythms
Enhancing adaptation to different light environments
Modern indoor living means melanin isn’t given the opportunity to do what it’s designed for. We’re essentially “unplugged” from one of nature’s most powerful healing tools.
Photobiomodulation: Light as Medicine
Photobiomodulation—sometimes called red light therapy—uses specific wavelengths (usually red and near-infrared) to stimulate mitochondrial function and reduce inflammation. But here’s the key: the sun provides these wavelengths every single day, especially at sunrise and sunset.
Our ancestors naturally received this healing light simply by living outdoors. Today, we often need devices because we’ve moved so far from natural patterns.
Sunrise and sunset light support:
Hormone balance
Mood stability
Mitochondrial repair
Healthy ageing and longevity
This is why that early morning light feels so grounding, and why watching the sunset often brings calm.
Ancestral Living and the Rhythm of Light
Indigenous cultures—much like the communities studied by Weston A. Price, whose research revealed not only their nutrient-dense diets but also their deep connection to the natural environment—lived in harmony with the natural light-dark cycle. They didn’t need to think about circadian health because their environment enforced it.
They:
Rose with the sun
Spent the majority of their day outdoors
Ate in alignment with daylight
Slept shortly after sunset
Their health reflected that alignment. Weston A. Price observed that these communities, despite living in vastly different climates and landscapes, maintained vibrant health, resilience, and emotional stability—conditions supported not only by traditional diets but also by their consistent exposure to natural sunlight and absence of artificial lighting. Today, we are indoors nearly 90% of the time. Our biology hasn’t caught up with this shift.
Just as we look to ancestral diets to guide healing, we must also look to ancestral light exposure.
The Missing Piece of the Healing Puzzle
When clients come to me with fatigue, anxiety, low mood, hormonal imbalances, gut issues, eczema, or chronic inflammation, one of the first things I ask is: How much natural light are you getting?
It’s often the missing piece.
Supporting the gut, nourishing the body with traditional foods, and addressing lifestyle patterns are essential—but without natural light syncing the body’s rhythm, healing can only go so far.
Simple Ways to Restore Your Natural Light Rhythm
1. Get outside within 30–60 minutes of waking
Even 5 minutes makes a difference. No sunglasses if possible.
2. Watch the sunrise or sunset when you can
These wavelengths help regulate melatonin and support mitochondrial health.
3. Take short outdoor breaks throughout the day
Think of it as light nutrition.
4. Reduce artificial light after sunset
Use lamps, warm bulbs, candles, or blue-light–reducing glasses.
5. Limit screens at least an hour before bed
Your sleep hormones will thank you.
Final Thoughts
Natural light is not optional—it is a fundamental part of human biology. As Randy Lee puts it, light contours our biology. It shapes our energy, mood, hormones, mitochondrial health, and even longevity.
As we move through the darkest part of the year, prioritising natural light—even in small ways—can make a profound difference.
This winter, try stepping outside a little more. Let the light touch your skin. Let your biology reconnect with the ancient rhythm it remembers.
Your mitochondria, your mood, and your long-term health will feel the difference.