Winter Flow 3: The Missing Winter Signal Keeping You Cold, Tired & Gaining Weight

In our last blog, we discovered the hidden biological switch animals use to thrive in winter: Activating the winter programming.

You learned that your body has two metabolic modes: summer and winter.

Which one runs depends entirely on the signals you receive from nature.

Today, we dive into the first force that controls that switch: LIGHT

Meeting the Sun

Picture this:

It's December 4th 2018.

6:15 AM. Still dark. -10°C.

I'm standing barefoot in the snow outside the farmhouse, waiting.

The sky is deep purple. Stars still visible. No sunlight yet.

But I'm here anyway.

Weeks earlier, the farmer had said something I couldn't forget:

"If you want to feel alive in winter, you have to greet the sun every morning.

And you have to develop a friendship with the crisp cold."

I remember thinking he was being poetic. Turns out, he was being scientific.

At around 8:30 am, the horizon begins to glow: Deep orange. Then pink. Then gold.

And the moment the first sliver of sun breaks the horizon, something shifts.

My body wakes up.

I feel energized.

I feel oriented.

Like my body suddenly knows what time it is.

And over the weeks of doing this, standing outside every morning, letting that early light hit my face, I notice something remarkable:

I start falling asleep earlier. Naturally.

I wake before my alarm. Without grogginess.

My energy stabilizes. No 2 PM crash.

My mood lifts. Even in the darkest months.

Some mornings, the sun breaks through cleanly.

Other mornings, it stays hidden behind thick winter clouds.

It doesn't matter.

I'm out there anyway.

Standing in the cold.

Greeting the sun: whether I can see it or not.

Why Morning Light Is Everything

Here's what most people don't understand about light:

It's not for vision.

95% of the light entering your eyes doesn't help you see. It regulates your hormones.

Your eyes have specialized cells called ipRGCs that detect light and send signals directly to your SCN: your brain's master clock.

That clock controls everything:

==> When you feel alert or sleepy

==> When your body temperature rises or falls

==> When you're hungry

==> When your metabolism speeds up or slows down

==> When your immune system repairs itself

Your entire physiology runs on the light signals your SCN receives.

And it needs the right light at the right time.

A 2018 study in Nature found these cells respond most strongly to the specific wavelengths of natural sunlight, especially the blue and cyan light at sunrise.

But here's the key: they need outdoor light to activate properly.

The difference is staggering.

Even on the darkest winter day, outdoor light is 20-100 times brighter than indoor light.

Indoor light doesn't trigger the full circadian response your body needs.

So what happens when morning light hits your eyes?

Within seconds, your ipRGCs signal your SCN.

Within minutes:

==> Cortisol rises (waking you up)

==> Serotonin increases (making you feel content and peaceful)

==> Body temperature climbs (energizing you)

==> Metabolism activates

But here's the critical part:

12-14 hours later, your pineal gland uses that morning light as a reference point to trigger melatonin production: your sleep hormone

The light you see at 8:00 AM determines whether you can fall asleep at 9:00 pm

Morning light wasn't just waking them up.

It was programming their entire 24-hour cycle.

Winter Light: Why You Need More, Not Less

Here's the cruel irony of winter:

The days get shorter. The sun gets weaker. You need light more than ever.

But you go outside less.

You wake up when it's still dark.

You walk 30 seconds from your house to your car.

You drive with sunglasses on. Windows block natural light.

You arrive at your office and sit under artificial lights all day.

You drive home in the dark.

You never see the sun.

And your body interprets this as: "I don't know what time it is. I don't know what season it is. I don't know what to do."

Your body needs enough light first thing in the morning to understand it's daytime.

And in winter, with weaker sun and shorter days, you need to be more intentional about getting it.

But morning light only solves half the problem.

There's another signal your body desperately needs in winter.

The seasonal signal.

What the Buffalo Knew

Back on the farm, I noticed something fascinating about the buffalo.

They didn't wait for the first snowfall to grow their winter coat.

By the time winter arrived, they were already bundled up in thick fur that helped them retain heat.

But how did they know?

It wasn't temperature. September was still warm.

It wasn't snow. The ground was still bare.

It was the UV light.

As summer shifted to fall, the UV index started dropping. Their eyes detected this change and sent the signal to their brain: "Winter is coming. Activate winter programming."

By the time the cold hit, their bodies had already made the switch.

Thicker fur. Slower metabolism. Mitochondria primed for thermogenesis.

Seamless. Automatic. Perfect.

Meanwhile, remember those caged chickens under 24/7 artificial lights?

They struggled. Got sick. Couldn't adapt.

Because they never received clear seasonal signals from UV light.

Your Seasonal Clock Runs on UV

Remember in Blog 2 when we talked about infradian rhythm, your body's yearly clock that tells you whether it's summer or winter?

That clock reads UV intensity.

In summer, abundant UVA tells your body: "Activate summer programming. Speed up metabolism. Stay active. Store fat for winter."

In fall, as UV decreases, your body receives the message: "Winter is coming. Switch to winter programming. Slow metabolism. Activate thermogenesis. Prepare for cold and darkness."

Why Modern Humans Stay Stuck in Summer Mode

Your body is designed to read UV light for two critical pieces of information:

What season is it? (Summer vs winter)

Where am I? (Equator vs northern latitude)

Think about it:

In Mexico, the difference between summer and winter UV isn't huge. Your body experiences relatively stable seasonal signals.

In Canada? The UV swing is massive.

Long, bright summers with 16+ hours of intense UVA.

Short, dark winters with maybe 4-6 hours of weak UVA (if you're lucky).

Your infradian rhythm needs to track this massive swing to adapt properly.

But modern life blocks the signal entirely.

You work indoors under LEDs. No midday UV.

You drive in cars. Windows block UV.

You spend fall and winter exactly like summer: same indoor temperature and same artificial light,

Your infradian rhythm never receives the signal to switch to winter programming.

So ponder on those questions:

How much natural midday light am I getting in fall and winter?

How much UV actually reaches my eyes and skin between September and March?

If the answer is "very little" or "none," your body is facing the same problem those caged chickens faced.

Seasonal confusion.

The Cost of Missing the Seasonal Signal

Without proper UV signaling in fall and winter, your body never gets the message to:

==> Activate brown fat

==> Increase heat production

==> Shift into winter's conservation mode

==> Prepare your mitochondria for thermogenesis

You stay stuck in summer programming. In December

Your mitochondria keep trying to produce quick energy (summer mode) instead of energy and heat (winter mode).

You feel cold all the time because you're not generating internal warmth.

You gain weight because your metabolism never shifted to fat-burning.

You're exhausted because your body doesn't shift into deep repair and rejuvenation mode in the winter

And you wonder what's wrong with you

You ponder why winter is so hard!

But here's the truth : Nothing is wrong with you and winter is not meant to be torturing

Your body just never got the right signal.

3 Actions to Receive the Seasonal Signal

Here's how to give your body what it needs:

In Blog 4, we'll explore what happens after sunset: how darkness completes the light cycle and why protecting it is just as critical as getting morning and midday light.

Continue Your Winter Flow Journey

The Science Behind This Blog