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My Winter Tips - Circadian Signaling

My Winter Tips - Circadian Signaling

Looking beyond Vitamin D Supplementation

Sylvie Oliveira
November 29, 2025

Respecting Light and Dark Cycles

For several years now, I’ve been reading and experimenting with how important it is to strengthen circadian signalling—the internal timing system that governs our hormones, mood, energy, and immune resilience.

Honouring the light and dark cycles of our days and seasons is one of the most powerful ways to support our health.

Back in 2020, when the world shut down, I began waking up with the sunrise and sun-gazing each morning. That fall, my vitamin D numbers were the best they’d ever been. I’ve been experimenting ever since.

Why This Time of Year Feels “Off” for Many People

As the days get shorter and the season shifts, many people notice:

disrupted sleep
sugar cravings
unusual symptoms
mood dips
low energy

We keep moving in our modern lifestyles as if nothing has changed—yet nature is shifting all around us. With the colder days we have a ton of excuses to not go outside and after the sun sets we continue to be exposed to blue light telling our body it’s the middle of the afternoon.

Trust me, this is challenging for me as I have two teenagers playing competitive volleyball.

This has been on my mind a lot.

How do I respect the dark and rest cycles of this season, while my teenagers are busy, and then to boot, I’m in a season of my hormonal life which is asking for more stillness and honouring of the body.

How do I honour all of it? Maybe that’s my next newsletter 😁…..but for now, let’s talk about circadian signalling.

What’s Actually Happening Inside You

Vitamin D is often framed as the winter “saviour,” but the story is more nuanced.
Your body relies on multiple seasonal cues—not just supplements—to regulate your immune system, metabolism, and repair processes.

Two of the biggest players are Vitamin D and Melatonin, and they work together in a beautifully coordinated seasonal dance.

As UVB Light Fades… Vitamin D Drops

In fall and winter:

UVB light decreases
Your skin produces far less vitamin D (or none, so we think)
Your immune rhythm shifts into its colder-season strategy

But maybe we are supposed to be making more of another hormone to help us in the winter months.

As Darkness Increases… Melatonin Rises

Melatonin is not just a sleep hormone.
It’s also:

a mitochondrial antioxidant
an immune regulator
an anti-inflammatory molecule
a cellular repair signal

With longer nights, your melatonin should naturally rise and release earlier—creating a protective, restorative rhythm that compensates for the drop in vitamin D.

This is part of how our ancestors survived winter.

❄️ Cold Sends a Signal to Your Mitochondria

Cooler temperatures tell your mitochondria to:

conserve energy
generate more heat
shift into a slower, restorative metabolic pattern
increase resilience

I recently learned that mitochondria actually emit light (biophotons) when exposed to cold.
This can be:

cold showers
cold plunges
stepping outside in winter
even briefly rinsing your face with cold water

Biophotons are ultra-weak pulses of light naturally produced during mitochondrial activity—mainly in:

near-infrared
red light
the UV-visible spectrum

Isn’t that fascinating?

Our cells literally emit red and infrared light.
And spiritual texts have reminded us for centuries that we are light. ✨

Science is simply catching up.

Vitamin D + Melatonin: Two Seasonal Partners

These two systems work together:

Vitamin D needs sunlight
Melatonin needs darkness
Both support your immunity and cellular repair
Both help regulate inflammation
Both shift throughout the year to protect you

Melatonin is produced not only in your pineal gland but also inside your mitochondria, and many other areas of the body! where it plays a major role in keeping your cells healthy.

Your cells depend on nighttime melatonin to:

repair oxidative damage
reduce inflammation
rebuild the nervous system
strengthen immune function
slow aging

What’s really interesting…morning light is what ensures this entire cycle begins properly.

To sum it up, in the winter season:

UVB and vitamin D fall
Darkness increases → melatonin rises
Cold exposure boosts mitochondrial signaling and energy efficiency

What About Near-Infrared Light?

We receive NIR light all day, even in winter.

Emerging research suggests NIR may help stimulate mitochondrial melatonin, which could act as an internal antioxidant during months when UVB is low.

Conclusion:
Get outside. Every day. Even in the cold.

Hiding indoors makes it harder for your body to activate its natural winter chemistry.

Why Morning Light Helps You Make Melatonin at Night

Most people think melatonin “appears” at night on its own.
But melatonin actually starts being made in the morning — and light is the switch.

☀️ 1. Morning light sets your body’s master clock

Inside your brain is the suprachiasmatic nucleus (SCN) — your circadian clock.
It tells every organ, hormone, and cell what time it is.

When morning light hits your eyes, it delivers a very specific message:

“The day has begun.”

This syncs your entire system.

Without that signal, your body has no clear anchor point, and melatonin production becomes irregular, weak, or mistimed.

🔆 2. Morning light suppresses melatonin at the right time

Morning sunlight contains:

Blue light
Green light
Red/infrared

When this light hits special receptors in the retina (melanopsin), it turns off nighttime melatonin.

This is good because your body needs:

High serotonin in the morning
High melatonin at night

These two hormones are linked like sunrise and sunset.

🌤️ 3. Morning light builds the ingredients to make nighttime melatonin

Melatonin is made from serotonin, and morning sunlight is one of the strongest boosters of serotonin production.

Morning light → serotonin
Night darkness → serotonin converts to melatonin

So you’re literally building tonight’s melatonin with this morning’s sunlight.

🕰️ 4. It starts a countdown to melatonin release

Once your brain gets the morning light signal, it starts an internal countdown timer:

If you skip morning light:

Your melatonin rhythm drifts
You fall asleep later
Sleep becomes lighter
Mitochondrial repair is weakened

Your whole day–night rhythm becomes confused.

🌙 5. Melatonin is produced in both your brain and your mitochondria

Even more importantly:

Melatonin = your body’s #1 mitochondrial antioxidant

Your cells depend on nighttime melatonin to:

Repair damage
Reduce inflammation
Rebuild the nervous system
Strengthen immune function
Slow aging

Morning light is the first domino that ensures that nighttime repair actually happens.

❄️ 6. In winter, morning light becomes even more important

Because:

UVB is gone or very low
Vitamin D drops
Immune stress increases
Days are shorter
Your melatonin should naturally rise

Nature balances this by giving us stronger blue and infrared in morning light during winter, to ensure we still regulate circadian rhythm even with low UV.

This is why respecting light cycles is protective in cold seasons.

Your circadian rhythm is literally linked to your environment, and it modifies itself based on temperature and the availability of light.

🌅 My Simple Light Habits

Morning Light

When natural light enters your eyes:

it switches off lingering melatonin
boosts serotonin
sets your circadian clock
starts a countdown to nighttime melatonin release

No morning light = weak melatonin, poor sleep, low mood, slower repair.

What I personally do:

As soon as I wake up (bathroom first 😁), I step outside.

Summer:
I sit on my deck at sunrise for 10–20 minutes, stretch, sometimes eat breakfast outside.
Winter:
I stand at the open door of my deck or in front of an open window, even for a few minutes.
If it’s very cold or snowy, I simply get as much natural light on my face as possible.
I go for a walk as close as possible to sunsrise.

It wakes me up in a way coffee never could.
My mood lifts.
And I can feel my hormones regulating and my nervous system waking up in harmony with nature.

❄️Your Winter Realignment Checklist

☀️ 1. Get outside within 30 minutes of sunrise

Cloudy? Cold? Tired?
Go anyway. Even just stand in front of your open door for 5 mins.
This regulates hormones, immune function, and your circadian rhythm.

Extra day tips:

leave your car window open a bit to allow the sunlight in while you drive.

limit sunglasses. Get the day light into your eyes.

🌙 2. Reduce nighttime blue light

Dim your lights after sunset.

Use warm, dim lighting at night.

Block blue light from screens after sunset. Orange blue-blocking glasses after sunset. Turn your phone screen to red.

Use circadian or red bulbs.

💧 3. Hydrate well

Indoor heating is dehydrating.
Add minerals and drink plenty of water.

❄️ 4. Lean into the cold

Short exposures add up fast:
morning walks, cold face rinses, cracking open a window, stepping outside without a coat for 20–60 seconds.

Brands I Personally Use

These are some of the brands I use to assist in my circadian signalling:

VivaRays blue blockers - https://vivarays.com/
Nira circadian light bulbs - https://niralighting.com/
Sweet Dreams Light Bulb - Block Blue Light
Kitchen Table lamp with red/yellow light bulb - ikea (after kitchen is closed 😁)
Sleep lamp - also use as evening light in bathroom - Block Blue Light

I hope this helps you find deeper rest, better sleep, and more steady winter energy.

With gratitude,
Sylvie

Healthy Recipe

Greek Lemon Chicken and Potatoes - The Best One Pan Dinner You'll Ever Make

I’m personally a one pan meal girl!