Let the Sun Shine In

Light, Rhythm, and the Way We Were Designed to Live

Every morning—literally every morning—when I open the blinds, I still think of my mom. She would burst into my room, full of energy I did not share, throw open the curtains, and sing:

"So let the sunshine in, face it with a grin

Smilers never lose and frowners never win

So let the sunshine in, face it with a grin

Open up your heart and let the sunshine in"

I remember being thoroughly annoyed. She did it with enthusiasm—too much enthusiasm, if you had asked me then. And yet it stayed with me.

Even now, years later, I open the blinds and think of that same line—not just as a memory, but as something that feels true. Recently, I went back and looked up the full lyrics, trying to remember exactly how it went, and I was struck by how much meaning was packed into something so simple.

They don’t really write songs like that anymore.

I didn’t start thinking about light all at once. It showed up in pieces over time—vitamin D, mood, things I was hearing on health podcasts. I began to understand that the connection between light and health is deeper than I realized. Light does more than just help us see. It influences how we feel, how we sleep, and even how our bodies function.

But it still felt like information—interesting, but a little disconnected from real life.

Until it wasn’t.

For me, one of those reasons was Lucia.

Lucia is my horse, and she has struggled with laminitis—a painful condition that forces me to pay very close attention to something most people never think about: the sugar content in grass.

That sugar is directly influenced by light.

As sunlight drives photosynthesis throughout the day, sugar builds in the grass. Overnight, the plant uses that stored energy for growth, which lowers the sugar content again by morning. So for much of the year, the safest time for Lucia to graze is early in the day, before the sun has had time to raise those levels again.

There’s more to it, of course. Time of year matters. Temperature matters. Cold nights can change the cycle.

But the point is simple: light isn’t just something we see. It’s something that shapes life, right down to the chemistry of grass.

Her name, which I chose years ago without much thought, means “light” in Italian. I didn’t know then how fitting that would become.

Around that same time, I started hearing more about light in a different context—not just sunshine in general, but the timing and type of light.

Morning light feels different for a reason. Step outside early, within the first hour of waking, and the crispness of a new day awakens your spirit. You feel more awake and clear-headed. 

Early light has a way of setting the tone for the whole day.

That early light, especially in the blue spectrum, enters through the eyes and helps set our internal clock, telling the body it’s time to wake up, to be alert, and to begin the day. It also shapes mood more than we tend to realize. There’s a reason people struggle more in the darker months. Less light doesn’t just change how the day looks; it changes how we feel.

As the day fades, the light shifts warmer. It’s not abrupt. Those softer, redder tones signal something different—time to slow down and prepare for rest.

And then there are the longer wavelengths: red and near-infrared light, which can penetrate deeper into the body. There is growing research into how this kind of light supports mitochondrial function, reduces inflammation, and plays a role in healing and recovery.

It made me start to wonder how something so constant, something we barely think about, could have such a significant effect on our health.

At one point, I wanted to see it all laid out—to understand where these different types of light actually fall, because I tend to understand things better when I can see them. So I put together a simple visual to make sense of it.

Different wavelengths of light affect the body in different ways.

Seeing it this way helped me connect the dots—how the bright blue light in the morning signals wakefulness, how the warmer tones in the evening help us wind down, and how those deeper red and near-infrared wavelengths play a role beneath the surface in ways we’re still learning about.

It’s all part of the same spectrum, just experienced differently depending on time of day and how we interact with it.

And yet, most of us spend the majority of our time indoors, away from all of it. We live under artificial lighting, on screens late into the night, exposed to bright blue light at times when our bodies are expecting darkness.

That matters more than we realize. Blue light in the evening can suppress melatonin—the hormone that helps regulate sleep—and interfere with the depth and quality of our rest.

I still catch myself doing it, even now—sitting at my computer long after the sun has gone down, working on a post and telling myself I’ll wrap up soon. But the issue isn’t just staying up late. It’s the light—the kind that tells the body to stay alert when it should be winding down.

I don’t always get it right, but I’ve started to notice the difference. When I stay on screens late, I feel it—not always right away, but later, when sleep doesn’t come as easily or doesn’t feel as deep. And on the days when I get outside early, when my eyes actually take in that natural morning light, things tend to fall back into place. I feel more awake during the day, and by night, my body is ready for rest.

It’s less about doing everything perfectly and more about giving the body the right signals at the right time.

There are other quiet benefits to being outdoors, too. This is one of those places where I tend to go down a rabbit hole.

Trees don’t just provide shade or look pretty. They release compounds called phytoncides—natural chemicals that help protect them from insects and disease. When we’re around them, we breathe those compounds in, and research suggests they can support our immune system, reduce stress, and even influence inflammation.

And it’s not all trees equally. Evergreens—like pine, cedar, and fir—tend to release higher concentrations, which may be part of why time in those forests feels different.

It’s another reminder that being outside isn’t just pleasant—it’s purposeful.

They don’t need to understand it. They just respond to it.

Caring for animals has quietly reshaped my life in that way—pulling me into a daily rhythm of being outside, paying attention to light, and living more in step with those natural patterns.

Morning, noon, and night, there are things that have to be done, no matter the weather or how I feel. In that rhythm, something shifts. It grounds me and pulls me back into the natural patterns of light and rest that God built into creation.

I see it in the animals themselves. My chickens lay fewer eggs in the winter—not because anything is wrong, but simply because there is less light. Their bodies respond to it naturally, without intervention.

There’s something about that simplicity that feels right.

That rhythm doesn’t just show up on the farm.

In the evenings, as I do my chores, I sometimes look out at the road that circles our neighborhood and see families walking—strollers, dogs, couples side by side. It’s one of my favorite things to notice.

They’re out there in that soft, fading light at the end of the day, the kind of light that gently tells the body it’s time to slow down and rest.

Most of them probably aren’t thinking about wavelengths or circadian rhythms, but they’re participating in something real.

Something intentionally designed.

It’s all connected: the light we wake up to, the light we move through during the day, and the light that closes it. And when you start to notice it, you realize how much of life was meant to follow that pattern.

Natural light helps regulate our circadian rhythm, supports hormone balance, and plays a role in mood, something we see clearly in seasonal affective disorder. Sunlight also enables our bodies to produce vitamin D, which is essential for immune function.

That connection shows up on a larger scale, too. In places like Australia, the “sick season” falls during their winter months—June and July—when daylight is shorter. It’s a reminder that what we often associate with time of year may be more deeply connected to light than we realize.

And the effect isn’t limited to vitamin D. Light exposure influences immune activity more broadly.

And it’s not just light. Heat plays a role too. Working outside in the summer, sweating more than I planned to, and adapting to it, may not feel comfortable, but it challenges the body in ways that can strengthen it. Some research suggests that heat exposure can increase interferon production, which plays a role in immune defense.

I don’t know that working in the yard is exactly the same as a controlled sauna, but it does make me wonder.

Sometimes I think, who needs to spend all that money on an infrared sauna when we’ve been given something far more accessible?

Creation has already provided one.

Of course, that doesn’t mean we ignore wisdom. There is still a place for shade, for rest, and for protecting our skin when the sun is intense.

But there is a difference between living with the natural world and living almost entirely apart from it.

And even that design is not accidental.

In the very beginning, before the sun, before the moon, before anything that marks time the way we understand it, God created light.

“And God said, ‘Let there be light,’ and there was light.” (Genesis 1:3)

Light came first—before structure, before cycles, before anything else that would depend on it.

It was foundational, both physically and spiritually.

And maybe that’s part of what we’re rediscovering now, in our own limited way: that light is not just something we use. It’s something we were designed to live within.

“The light shines in the darkness, and the darkness has not overcome it.”  (John 1:5) “For God, who said, ‘Let light shine out of darkness,’ has shone in our hearts to give the light of the knowledge of the glory of God in the face of Jesus Christ.” (2 Corinthians 4:6, ESV) “Your word is a lamp to my feet and a light to my path.” (Psalm 119:105)

Light does something nothing else quite can. It makes the hidden visible, clarifies what is real, and exposes what we might otherwise miss.

But it also reflects something about design. The same light that orders our days, guides growth, affects our bodies, and sets rhythms across creation is the same light Scripture uses to describe truth. That doesn’t feel accidental.

Because light doesn’t just illuminate. It reveals. It pushes back darkness, not just around us, but within us.

And in that light, things become clearer—what is true, what is good, and what leads to life.

So every morning, when I open the blinds, I still hear her voice:

“Open up your heart and let the sunshine in.”

And for once, I don’t find it annoying.

I understand it.

Note: The song “Open Up Your Heart (And Let the Sunshine In)” was written by Stuart Hamblen. It was first used in his Cowboy Church Sunday School program and later made its way into popular culture, including an appearance on The Flintstones. I recently looked up the full lyrics, and they’re more meaningful than I remembered. My favorite version is the original: "Open Up Your Heart (And Let The Sunshine In)" & "It Is No Secret" by Stuart Hamblen