Infrared Light, Mitochondria and Metabolic Health

I've become increasingly interested in something that is all around us but that we rarely think about — light.

Light isn't simply something that allows us to see. Different wavelengths interact with our biology in very different ways, and one of the most interesting is red and near-infrared light, particularly its relationship with the mitochondria.

Infrared has always been part of our natural environment. It is abundant in sunlight and is also produced by fire and traditional incandescent bulbs. Our ancestors would have been exposed to it naturally throughout the day, particularly during the lower sun of morning and evening.

Almost everything our bodies do ultimately depends on energy. Movement, brain function, hormone production, immune function, tissue repair, maintaining body temperature and even the basic processes that keep a cell alive all require energy. The mitochondria sit at the centre of this process. They convert the food we eat and oxygen we breathe into ATP, the energy currency used by our cells.

They are also involved in controlling oxidative stress, cellular signalling, inflammation, calcium regulation and whether damaged cells survive or are removed. This means that healthy mitochondria are fundamental to metabolic health and to the normal function of almost every tissue in the body.

When mitochondrial function is impaired, the consequences can extend far beyond energy levels. Mitochondrial dysfunction is associated with ageing and a wide range of metabolic and chronic diseases, ranging from diabetes to most cancers, which is why maintaining mitochondrial health has become such an important area of research.

This is where infrared becomes particularly interesting.

Research into photobiomodulation suggests that red and near-infrared wavelengths can interact with mitochondrial chromophores such as cytochrome c oxidase, an important component of the electron transport chain.

This interaction may influence electron transport, mitochondrial membrane potential and ATP production, while also affecting nitric oxide and reactive oxygen species. These changes can act as signals that influence cellular repair, inflammation and antioxidant defence.

In other words, light can interact with the machinery responsible for producing cellular energy.

If the mitochondria are central to our metabolic health, and particular wavelengths of light can influence mitochondrial function, it makes sense that regular exposure to these wavelengths could have effects that extend well beyond the skin.

This is one of the reasons I find infrared so fascinating.

There is also something particularly interesting about whenwe are exposed to infrared naturally.

The spectrum of sunlight changes throughout the day. When the sun is low in the morning and evening, the relative proportion of longer wavelengths, including infrared, is greater.

There is evidence that early exposure to near-infrared may also have a protective or photopreconditioningeffect, helping cells cope with the oxidative stress associated with subsequent UV exposure. Experimental research has shown that near-infrared exposure can induce cellular defences against later UV stress.

It raises an interesting possibility: perhaps the natural sequence of light throughout the day is not accidental. Morning light provides a broad spectrum containing infrared before the stronger midday UV exposure, while evening light once again shifts towards the longer wavelengths.

Our biology evolved within this environment.

Today, our relationship with light is very different.

We spend much of our lives indoors, surrounded by LEDs, screens and artificial lighting. We can wake up under artificial light, spend the entire day under it and then sit in front of a bright screen until the moment we go to bed.

Modern artificial lighting can create a very different spectral environment from natural daylight, fire and incandescent light. Traditional incandescent bulbs, for example, produce a broad, warm spectrum with substantial infrared because the filament becomes extremely hot. Fire is another natural source of infrared.

It is interesting that both of these familiar light sources are rich in the longer wavelengths that are largely absent from many modern artificial environments.

If mitochondria are fundamental to how our cells produce energy and regulate themselves, then anything capable of positively influencing mitochondrial function becomes interesting from a metabolic perspective.

Rather than thinking about infrared as simply something that makes us feel warm, we can think of red and near-infrared light as a biological signal that may influence one of the most fundamental systems in the body — the mitochondria.

And because mitochondria are present in almost every cell and are involved in energy production, metabolism, signalling and repair, the implications of supporting mitochondrial function could potentially extend across many aspects of health.

Perhaps this is why our natural environment has always contained so much infrared.

We didn't evolve under LED lighting. We evolved under the sun, around fires and in darkness at night. Light is part of our environment, and our cells have evolved to respond to it.

Infrared light can also pass through clothing., so one of the easiest ways to get more infrared exposure, is to go for a morning (or evening) walk. This also aligns with the many other benefits from this practice.