There’s a rhythm beneath everything: the tide, your breath, the rise and fall of the sun. But the rhythm that most quietly—and most profoundly—shapes how we feel, think, and rest… is your circadian rhythm: the internal clock rooted deep in your brain and body that syncs you with the cycles of light and dark.
On this Sacred Saturday, we’re exploring how light—especially in the short, cool days of winter—affects your internal timing, mood, sleep, hormones, and even your sense of vitality. We will also explore how ancient cultures understood and celebrated this balance long before science could explain it.
🧠 The Science Behind Your Internal Clock
At the core of your circadian rhythm is a tiny region of your brain called the suprachiasmatic nucleus (SCN). This master clock responds directly to light entering your eyes—especially blue light wavelengths—and uses that signal to tell your body what time it is:
- Morning light tells your brain to release cortisol and serotonin—so you feel alert and calm.
- Evening darkness triggers melatonin—so you feel sleepy and restorative.
Researchers can measure the timing of these hormones in the blood and saliva and observe how light exposure shifts them earlier or later in the 24-hour cycle. Sleep labs do this with dim light melatonin onset (DLMO) tests and actigraphy (wearable movement/sleep monitors), illustrating just how sensitive our rhythms are to light.
Short Winters, Limited Light
As daylight shrinks in winter:
- Cortisol peaks later → you sleep in but might still feel groggy
- Melatonin rises earlier and stays elevated longer → sleepiness often lingers during the day
- Serotonin decreases → your mood may be lower and you might notice changes in appetite
Clinically, this pattern underlies Seasonal Affective Disorder (SAD)—a form of depression that appears at roughly the same time each year—measured by mood questionnaires and circadian hormone changes. Even if you do not experience SAD you might still feel the impacts of the seasonal change.
Changes you might notice include:
✔️ Sleeping more but not feeling refreshed
✔️ Trouble waking up in the dark morning
✔️ Afternoon dips in mood or energy
✔️ Cravings for carbs and comfort foods
Your willpower isn’t failing you—this is simply biology responding to the season.
🌿 Wisdom from the Ancients: The Inuit and The Light
Before electric lights, cultures around the world lived in harmony with the solar cycle. One tradition I deeply admire comes from the Inuit of the Arctic, where daylight disappears for months and returns slowly in spring.
In the long Arctic winters, when the sun barely lifts above the horizon, traditional, Inuit communities of the past (and many still in modern day) did not resist the darkness but, rather, organized their lives around it. Evenings were spent gathered closely around shared fires, not only for warmth but for connection and consistency. Stories were told. Songs were repeated. The same voices, the same faces, the same timing, night after night. These simple togetherness practices are actually powerful forms of regulation- emotional, social, and biological regulation. We now have a name for it in modern science: social synchrony. Social synchrony is the term used to describe the way shared routines and collective presence help nervous systems align, lowering stress hormones and stabilizing internal clocks for the entire group.
Throughout the darkest months, light itself helped support well-being. Firelight—soft, warm, and low—filled homes instead of the harsh brightness we rely on today. That red-shifted glow allowed melatonin to rise naturally in the evening, supporting deeper sleep and calmer nervous systems. Modern research now confirms what Inuit families lived by instinct: warm, dim light at night protects sleep and emotional regulation, especially during long seasons of darkness when light is scarce and the body struggles to find a rhythm.
The intuit also had customs to mark the retreat of winter and the return of longer days. The return of the sun was celebrated with Quviasukvik, a time of music, movement, and communal outdoor activity that started with sunrise. These early morning gatherings weren’t just symbolic gratitude for light; they pulled bodies back into rhythm with the day. Today we know that exposure to morning sunlight is one of the most effective ways to reset circadian timing—helping the brain shift toward earlier wakefulness, improved mood, and greater daytime regulation.
These practices were not merely cultural or spiritual expressions. They were intelligent, embodied adaptations to an extreme environment—ways of supporting human biology in harmony with the rhythms of light and dark. Now modern science explains what these communities already knew through their close ties to nature.
🧠 What’s Actually Measurable in Your Body
When we talk about circadian rhythms, it can sound abstract—like something theoretical or loosely defined. But this system is not guesswork. Researchers can see circadian shifts happening in the body in very concrete, measurable ways. Light doesn’t just influence how you feel; it changes what your body is doing at a biological level.
One of the most closely tracked markers is melatonin, often called the sleep hormone. Scientists measure melatonin through saliva or blood samples to determine when it begins rising in the evening and when it falls in the morning. In winter, with reduced exposure to morning light and longer periods of darkness, melatonin often begins rising earlier in the day and stays elevated longer into the morning. This shift helps explain why people feel sleepy earlier in the evening, struggle to wake up, or feel foggy and slow even after a full night’s sleep. The body’s internal night simply lasts longer.
Researchers also track core body temperature, which follows a reliable circadian pattern. Under normal conditions, body temperature drops in the evening as the nervous system prepares for sleep, reaching its lowest point in the early morning hours. Light—especially bright or blue-leaning light—can delay this drop. In winter, inconsistent or poorly timed light exposure can blur this temperature rhythm, leaving the body stuck between “day mode” and “night mode.” The result is often restless sleep, frequent waking, or difficulty settling down in the evening.
Another key measurement comes from activity and rest cycles, often captured through wearable devices using a method called actigraphy. These devices track movement over time and reveal patterns in sleep onset, nighttime awakenings, and daytime energy. In seasons with limited daylight, actigraphy frequently shows delayed sleep onset, more fragmented sleep, and less stable day–night rhythms, even when total sleep time looks adequate on paper.
When scientists look at these markers together—melatonin timing, body temperature rhythms, and activity-rest cycles—a clear picture emerges. Light is not just a background condition. The timing, quality, and consistency of light exposure actively shape physiology. When light cues are misaligned, the body’s internal systems lose their rhythm, and everything from mood to focus to emotional regulation becomes harder.
This is why seasonal shifts can feel so powerful—and why small, intentional changes in light exposure can have outsized effects on how we function, feel, and regulate.
🌞 Strategies You Can Use Today
Whether you’re deep in winter’s shadow or welcoming lengthening days:
🌅 1) Morning Light First Thing
Get at least 20–30 minutes outside within an hour of waking—even on cloudy days.
This helps recalibrate your clock toward earlier alertness.
💡 2) Bright Days, Dim Nights
- During the day: seek bright, natural light
- After sunset: soften your lights; avoid screens 1–2 hours before bed
🌀 3) Anchor Your Activities
Try to move meals, exercise, and sleep times consistently—your body clocks appreciate predictability.
🔥 4) Warm Indoor Lighting
Use lamps or red/yellow lights in the evening instead of blue-rich overheads. (We string fairlights all through the house in winter and I swear I can feel the change in mood for all of us!).
🤝 5) Community & Ritual
Even a short evening ritual—like a family dinner with soft lighting or a shared walk after dinner—syncs social and biological rhythms.
🏡 At-Home Practice: Light Mapping Your Week
Your Sacred Saturday Light Practice:
- Track your light exposure
- For three days, note when you first see strong daylight
- Note when you dim lights at night
- Adjust intentional light
- Morning: considering the timing you observed, expose face and eyes to bright light (20–30 min)
- Evening: shift to warm bulbs or candlelight 2 hours before bed
- Ritualize sunrise or sunset
Each day this week: take 2 minutes to stop and breathe outside at sunrise or sunset—honoring your day’s beginning or ending.
📌 TL;DR — Sacred Saturday
In winter, short days shift your circadian rhythms—later melatonin, delayed cortisol, lower energy and mood. Ancient cultures like the Inuit responded with firelight, community gatherings, and seasonal dawn rituals—practices now supported by science. To thrive: get morning light, keep bright days and dim nights, and build simple light rituals into your life.
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Begin Within
and align with the rhythm of nature and self.
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