Before there were dogs, before there
were mammals, before there were animals of any kind, there was light. And life,
right from the very beginning, learned to use it. That story is still going on
— inside your dog, right now.

Here is something that sounds almost too simple to be
interesting: your dog is powered by light.

Not in a vague, poetic sense. In an actual, measurable,
biological sense. The cells in your dog’s body — every single one of them —
contain machinery that responds to light. That machinery has been there for
billions of years. And understanding it is the key to understanding one of the
most exciting developments in animal health right now.

Welcome to Part 1 of our series on photobiomodulation.
Let’s start at the very beginning.

What is light, exactly?

Light is energy. More specifically, it is electromagnetic
radiation — a stream of tiny packets of energy called photons, travelling at
around 300,000 kilometres per second.

The light you can see — the stuff that makes rainbows —
is only a tiny slice of a much bigger spectrum. At one end you have
ultraviolet, which is energetic enough to burn skin. At the other you have
infrared, which we feel as warmth but cannot see. Visible light sits in the
middle, covering the colours from violet through to red.

In photobiomodulation, or PBM, we are mainly interested
in red light (roughly 630 to 660 nanometres) and near-infrared light (around
800 to 850 nanometres). These are specific wavelengths that have a remarkable
property: living tissue absorbs them and does something useful with them.

“Life didn’t just evolve to tolerate light. It evolved to use it. That is a very different thing.”

Life and light: an ancient relationship

To understand why light affects your dog’s body, you need
to go back about 3.5 billion years.

The first living things on Earth were single-celled
organisms floating in the primordial ocean. The sun was hammering down on the
surface. And some of those early cells figured out something extraordinary:
they could harvest the energy in sunlight and use it to power their own
chemistry.

This was the beginning of photosynthesis — the process
that plants still use today. But it was also the beginning of something
broader. Life, at its most fundamental level, learned to be photoreactive. It
learned to sense light and respond to it.

As organisms became more complex, they kept that
relationship with light. They developed circadian rhythms — internal clocks
driven by the cycle of light and dark. They developed pigments that absorb
light for all sorts of purposes. And their cells kept the ancient machinery
that uses light energy to drive chemical reactions.

Your dog is the product of 3.5 billion years of that
evolutionary story. Every cell in its body carries the legacy of life’s deep,
ancient relationship with the sun.

The power station inside every cell

Here is where it gets genuinely fascinating.

Inside almost every cell in your dog’s body — in its
muscles, its skin, its joints, its nerves — there are tiny structures called
mitochondria. You may have heard them described as the ‘powerhouses of the
cell,’ which is accurate but undersells them slightly. They are extraordinarily
sophisticated biological machines whose main job is to convert fuel (from food)
into a form of energy the cell can actually use.

That usable energy comes in the form of a molecule called
ATP — adenosine triphosphate. Think of ATP as the cell’s rechargeable battery.
Almost everything a cell does — repairing itself, fighting inflammation,
sending signals, building new tissue — runs on ATP.

Now here is the crucial part. Mitochondria contain a
protein called cytochrome c oxidase. And cytochrome c oxidase absorbs red and
near-infrared light.

When it absorbs those photons, it works more efficiently.
It produces more ATP. The cell has more energy. And a cell with more energy can
do its job better — whether that job is healing a wound, calming an inflamed
joint, or repairing damaged tissue.

INSIDE THE CELL: WHAT LIGHT MAY TRIGGER

    • More ATP production — giving cells more
      fuel to repair and regenerate
    • Reduced oxidative stress — less of the
      cellular ‘rust’ that accumulates with age and injury
    • Improved local circulation — better
      blood flow to the area being treated
    • Modulation of inflammation — helping the
      body’s response stay useful rather than becoming harmful
    • Faster tissue repair — more energy means faster rebuilding

This is not speculation. The absorption of red and
near-infrared light by cytochrome c oxidase is well established in the
scientific literature, and its downstream effects on cellular energy production
have been demonstrated in numerous laboratory studies. It is worth being honest
here: demonstrating a mechanism in a laboratory is not the same as proving a
clinical outcome in a living animal. The research is promising and growing, but
it is still maturing. That is part of what makes this field so interesting to
follow right now.

So why does any of this matter for your dog?

Dogs age. They get injured. They develop arthritis. Their wounds sometimes struggle to heal. Their joints ache. Their nervous systems, under the pressure of chronic pain or chronic stress, can get stuck in patterns that make everything worse.

All of these problems have a cellular dimension. At the
level of individual cells, something is not working as well as it should.
Mitochondria are under-performing. Energy production is reduced. The repair
processes are sluggish.

Light therapy — PBM — is a way of giving those cells a nudge. Of using specific wavelengths of light to top up the energy supply and help the cell do what it is already trying to do.

It is not a drug. It does not force the cell to do something unnatural. It is, in a very real sense, working with biology rather
than overriding it. And that is part of why it is generating so much genuine
scientific interest right now.

“PBM is not asking the cell to do
something new. It is giving it the energy to do what it already knows how to
do.”

How does this work in practice?

Devices like the Photizo Vetcare deliver red and
near-infrared light at specific wavelengths directly to the tissue. The device
is held close to or gently touching the skin, and a pre-set dose of light is
delivered in around 30 seconds per treatment point. The owner moves the device
systematically across the area of interest, building up coverage.

Because the device handles the dose calculation
automatically, there is no need to understand the physics to use it safely. But
understanding the physics — even a little — helps explain why it works, and why
some conditions respond better than others.

In the articles that follow, we will go deeper: into the
specific biology of pain, inflammation, wound healing, and arthritis. We will
look at what the evidence says, and what it does not yet say. And we will
explore some findings from recent research that are genuinely surprising —
including the discovery that light may do things inside the body that nobody
expected.

The short version

Your dog runs on light in the same way that all life on
Earth does — because life evolved in sunlight, and the machinery of the cell
has been shaped by that relationship for billions of years.

The mitochondria in your dog’s cells absorb red and
near-infrared light and use it to produce more energy. More energy means better
repair, less inflammation, and less pain.

That is the foundation of photobiomodulation. Everything
else builds from there.

Next time: we go inside the cell and look at exactly how
the mitochondria work, and what happens when they are given a boost by the
right kind of light.

About the Author

Dr. Nick Thompson BSc (Hons) Path Sci., BVM&S, VetMFHom, MRCVS, is a fully trained vet with over 39 years of experience in raw food nutrition, herbal and homoeopathic as well as conventional medicine.

He uses both holistic and conventional practices, along with a hefty dose of old-fashioned common sense, to try to establish what is really wrong with his patients and what is required to help repair them. Minimising pharmaceutical intervention is at the heart of all treatments. 

Nick has a special interest in immunology, internal medicine, holistic health, and microbiome dynamics.

Working closely with friends and colleagues in the veterinary world, he, together with patients and owners, forms a hardworking team focused and committed to improving dog welfare, health and behaviour.

Holisticvet is based near Bath, Somerset (UK).

Light, Life and Your Dog is a ten-part series by Nick Thompson.

For more on integrative animal health, follow @holisticvetuk on Substack.