Light as a Nutrient: Sunlight, Circadian Rhythm & Metabolic Health | Dr. Max Gulhane

Let's get into light.

Before we're going to be talking a lot about light in this conversation.

So before we get into that, I would love if you could just give like a little like elevator pitch definition of like, what is light? What is it physically? I know, you know, we most people think of light, oh, just something I see, it helps me see things.

But we're going to talk about much more than just that.

So just before we like begin there, what is light in to begin with? What is it?

Yeah, I mean, light means different things depending on your perspective, to a physicist, to a photobiologist.

I mean, fundamentally, light is electromagnetic radiation.

It's radiation that's emitted from our sun, which is essentially a star, and it is essentially the waste energy that gets ejected from a sun.

and from the sun and it it exhibits physical properties that are both wave wave-like and particle-like and that i guess you can think about determine its its behavior um and then really by the time it hits us on planet earth it's both a it's both an environmental signal and a trigger for biological processes, but it's also energy.

And it's also a source of energy that facilitates human metabolism.

And I would say not only human metabolism, but metabolism of almost all life on earth.

So it's beyond what, it's so much more than what we can actually see because the visual spectrum restricts our perception of light to between 400, approximately 700 nanometers.

However, below that, there's light present, which is restricted by the atmospheric filtration because we don't get all the shortwave-like light, thankfully, and that's very high-energy light.

And the light extends beyond our visible perception into the infrared.

And for better or for worse, and what we can see is not all that there is, and all that there is, is actually playing a role in biology and our body's functions.

And when we think about our needs, the design specification of the body, those design specifications include a purpose for light that's not visible, whether that's shorter wavelength non-visible light in ultraviolet and longer wavelength light in the infrared.

But because of the way perhaps we think and we work reductionistically in today's modern life, and this is actually a mental model or I guess you could say a failure of mental thinking, a heuristic, which is that, you know, all we can see is we think that's all there is.

And it's to our detriment because we ignore a lot of the value of the solar spectrum, which, as I said, is triggering biological processes.

It's providing information about time of day, time of year, season.

It's providing information energy, it's writing instructions to cells, and that all is occurring in a way that the body has adapted to use, to make use of.

So in short, I think light is a valuable nutrient.

It's energy, it's nutrition, metaphorically speaking, and it's an essential part of living optimally for homo sapiens.

Amazing.

That's very well said.

I love how you talk about light as a nutrient.