Practical steps to use sunlight and darkness as medicine for your hormones and whole body health — from sunrise to sleep.
to know.
The sun isn\'t just an arbitrary source of light for plants to grow. As humans, our ancient DNA evolved with its most steady guarantee: that the sun would always rise, and always set.
Light and darkness each send completely different signals to our bodies about what time of day it is. Our cells literally harness the energy from sunlight to create their own energy. And it turns out, we have things called CLOCK genes, throughout every cell and organ in our body, that rely on those time-of-day signals from light (or darkness) to function optimally.
Blue light sets our biological clocks. It\'s naturally present in sunlight from after sunrise, peaks around midday, and reduces as sunset approaches. We\'re also exposed to blue light through screens and LED lights.
Blue light signals daytime → stops melatonin production (melatonin = sleepy).
Darkness and the absence of blue light signals night → amplifies melatonin production.
Most people think of melatonin as a sleep supplement. But melatonin is found in almost every part of your body. It acts as a vital antioxidant, anti-inflammatory compound, and plays a role in multiple disease states.
To put it into perspective: anything more than a single candle flame, 1 foot from your face, can begin to actively suppress your melatonin. Now consider how much light you\'re exposed to after sunset each night.
The guiding principle of this guide is simple: we want as many opportunities throughout the day — from sunrise to sunset — for natural light exposure, so our bodies know what time it is and can thrive. And after sunset, we want to remove or block as much blue light as possible. Perfection is not the aim. Real, doable change is.
Strategies
Red & infrared light at sunrise signals your mitochondria to make pregnenolone — your master steroid hormone and the starting point for all sex hormones (oestrogen, progesterone, testosterone) and cortisol. Getting this light is one of the most important hormonal acts of your day.
UVA hitting your bare eyes converts amino acids in the retina into dopamine, noradrenaline & serotonin precursors. It also initiates the skin\'s urocanic acid response — your best natural defence against UV damage later in the day. This requires bare eyes (no glasses, no sunscreen).
| Situation | Good Start | Better | Most Ideal |
|---|---|---|---|
| On waking | Go outside within 90 mins of waking for 5+ mins, bare skin on face & forearms | Outside within 30 mins of waking; view the sky even if cloudy | View sunrise directly, face east, bare eyes (no glasses or contacts), barefoot on earth if possible |
| Morning routine | Have your coffee or breakfast outside | Warm water on waking before caffeine; eat within 90 mins of waking | Warm water → sunrise view → breakfast outdoors → morning outdoor walk or exercise |
| Screens & indoor work | Sit near a window; take a 10-min outdoor break mid-morning | DayMax yellow-lens glasses when on screens indoors | Outdoor breaks every 90 mins; work near a window + DayMax glasses on screens |
| Sun protection | SPF on face only if needed AFTER first 10–20 mins of bare exposure, including no sunglasses | No sunglasses or SPF for first 20 minutes of morning light exposure | No sunglasses, no sunscreen (including SPF makeup) during morning window. Only use shade if at risk of burning, less likely in morning light |
| Situation | Good Start | Better | Most Ideal |
|---|---|---|---|
| UVB exposure | 20-min outdoor break during UVB window (check D Minder or MyCircadian app) | 30–45 mins bare skin in UVB window; short sleeves minimum | 2 × 30–60 min outdoor breaks; expose abdomen to sunlight for gut microbiome benefits |
| Sun protection | Aim for 10 minutes within UVB window with no sunscreen or sunglasses | Spend 20 minutes outdoors, applying sunscreen after 20 mins if UV index is high / based on your unique risk | Spend 20–60 minutes outdoors, using only shade and clothing as sun protection if needed (please avoid burning) |
| Lunch & breaks | Eat lunch near a window | Eat lunch outside when possible | Lunch outside + short outdoor walk; outdoor meetings or phone calls |
with the Sun
As blue light recedes and red/infrared rises at sunset, melatonin production is permitted to begin. IR and red light at this time stimulate BDNF (brain-derived neurotrophic factor) for neurological repair overnight. Watching the actual sunset — even 10 minutes — sends a clear "day is ending" signal to every cell in your body.
A single LED bulb can suppress melatonin by over 50%. Even 30 lux — equivalent to a single candle 30cm away from your face — can suppress melatonin. Your phone screen tells your brain it\'s solar noon. This doesn\'t just affect sleep. It affects your hormones, immunity, digestion and gut health, blood sugar, and cancer risk.
| Situation | Good Start | Better | Most Ideal |
|---|---|---|---|
| Sunset itself | Quick 5-min outdoor break around sunset | 20 mins outdoors around sunset, bare eyes | Spend 30–60 mins outdoors from golden hour through sunset |
| Indoor lighting | Dim existing lights after sunset; wear NightFall red-lens glasses | Switch to amber/warm lamps; red light bulbs in bedroom | Candles or fire only after sunset; no electric lighting after dark |
| Screens & devices | NightFall glasses when on phone, TV or laptop | NightFall glasses + red/night screen mode on all devices | No screens or devices after sunset |
| Evening meals | Finish eating at least 2 hours before bed | Last meal 3 hours before bed | Eat before or at sunset; all meals within daylight hours |
For after sunset — maximum blue light blocking for optimal melatonin protection. Wear for all screen use and under indoor lighting.
Shop NightFall →For screen use during daylight hours. Reduces strain and artificial blue light without distorting colour perception.
Shop DayMax →Swap your bedside lamp globe to red. Zero blue light. Supports melatonin production and deep sleep quality.
Shop Red Bulbs →For reading or winding down at night — no melatonin suppression, no sleep disruption.
Shop Reading Light →Medicine
During deep sleep and darkness, your body runs its most critical overnight programs: glymphatic clearance (brain waste removal — linked to Alzheimer\'s prevention), hormone synthesis, immune regulation, and cellular repair. Your melatonin peak at 2–4am is what drives this. Any light exposure — even through closed eyelids — can disrupt it.
| Light Condition | Lux Level |
|---|---|
| Direct sunlight | 32,000 – 100,000 |
| Ambient daylight | 10,000 – 25,000 |
| Overcast sky | 1,000 |
| Sunset / Sunrise | 400 |
| Full moon | 1 |
| Night (no moon) | <0.01 |
≤10 lux from 3 hours before bed (most home LED lighting is 100–500 lux).
≤1 lux in your sleeping environment.
Use a free lux meter app to check yours.
| Situation | Good | Better | Best |
|---|---|---|---|
| Bedroom light | Draw curtains; turn off lights | Red bulb or red reading light only | Fully blacked-out room; zero light sources |
| Eyes & skin | Wear NightFall glasses if any light is on | Sleep mask to block eye exposure | Blackout blinds + sleep mask + skin covered |
| Devices | NightFall glasses + red screen mode on phone | Devices off 1 hr before sleep | No devices after sunset |
| Night waking | Dim red lamp only if needed | Red night light in bathroom/hallway | Navigate in darkness if safe to do so (use small red light if needed) |
iPhone X and newer:
- Settings → Accessibility → Display & Text Size → Colour Filters
- Enable Colour Filters → select Colour Tint
- Drag both Intensity and Hue sliders to maximum
- Shortcut: Settings → Accessibility → Accessibility Shortcut → Colour Filters. Triple-press side button to toggle.
Practical FAQs & recommended resources to get you started.
Cloud cover reduces but does not eliminate UV and visible light. Even on overcast days, outdoor exposure is significantly better than indoor artificial light. More time is needed on cloudy days to achieve equivalent benefit. Go outside regardless.
Try to spend a portion of morning time without your glasses if safe. During screen time, clear blue-light blocking lenses can be made in prescription — Block Blue Light offer prescription options. NightFall glasses can be worn over prescription frames in the evening.
The key is to get your 10–20 minutes of bare skin exposure in the early morning UVA window before you apply SPF. The skin\'s protective response to UV is initiated in those early minutes, and SPF can be applied after if truly needed. It\'s also important to note that SPF is not required every day, and modern use tends to be excessive. When UVB is not available, SPF is unnecessary. Use the QSkin Risk Calculator to assess your unique risk of burning.
Use the D Minder or MyCircadian app to identify when UVB is available in your location. When it is available, prioritise it. In periods of very limited UVB (e.g. winter at high latitudes), supplemental Vitamin D is a reasonable short-term bridge, but is not a full replacement for the Vitamin D cascade initiated by sunlight.
Start slowly, especially after periods spent indoors. Begin in early spring with 5–10 minutes per day of bare skin exposure, gradually building tolerance. Check the QIMR QSkin Risk Calculator to understand your personal risk profile. Target the lower-UV morning window rather than solar noon, and use shade and clothing as needed.
Yes — circadian rhythm directly governs the HPG axis (progesterone, oestrogen, testosterone), the HPA axis (cortisol), thyroid function (TSH), and melatonin, which has a specific role in PCOS/PMOS, fertility, and mitochondrial health (including egg quality). Optimising your light environment is not an alternative to clinical investigation, but it is a foundational layer that makes everything else work better.
Also: D Minder app (Vitamin D tracking) · MyCircadian app (UVA/UVB windows for your location) · Lux Meter app (measure light in your home)
Circadian rhythm is one of the foundational layers of whole-body health — but if you have hormonal symptoms that haven\'t resolved, there\'s often more to investigate. Period pain, PCOS, PMS, irregular cycles, fatigue, hormonal skin, post-pill disruption — these are the things I work through in depth in Harmonised Hormones, a 3 or 6-month one-on-one naturopathic program built around a thorough investigation of what\'s actually driving your symptoms.
Book a free Body Story Call — 15 minutes, no obligation. You share what\'s going on, I tell you honestly what I\'m noticing and how I\'d approach your case. You leave with more clarity than you came with, regardless of what you decide next.
→ karindawholistix.com.au
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The Nuanced Naturopaths — Karinda John & Julie Forrester
Karinda helps women decode what their bodies have been communicating through their symptoms, cycles and hormones. She has a deep passion for female health, menstrual cycle literacy, and teaching women to understand the wisdom their bodies carry. She is the host of the Oh My Menses podcast and creator of Harmonised Hormones. You can find her at karindawholistix.com.au and on Instagram @karinda.wholistix.
Julie is a researcher and clinician with a focus on the gut microbiome and its relationship to whole-body health, as well as complex health in perimenopausal women. She brings evidence-based rigour to emerging areas of naturopathic practice, and co-hosts The Nuanced Naturopaths podcast alongside Karinda. You can find her at jforresternaturopath.com.au and on Instagram @julie.forrester.naturopath.
Karinda and Julie co-host The Nuanced Naturopaths podcast — a show where two degree-qualified naturopaths and self-confessed questioners of everything dance in the grey areas of health, busting myths about natural medicine and exploring the most up-to-date evidence. This guide grew out of their NHAA (Naturopaths & Herbalists Association of Australia) presentation, "Returning to Our Natural Rhythm: Circadian Signalling for Whole Body Health", delivered in 2025.
Karinda Wholistix
🌐 karindawholistix.com.au
🎤 The Nuanced Naturopaths Podcast
🎤 Oh My Menses Podcast
📷 @karinda.wholistix
📅 Book a free Body Story Call
🌿 Free Cycle Tracking Guide
💈 Harmonised Hormones
Julie Forrester Naturopath
🌐 jforresternaturopath.com.au
🎤 The Nuanced Naturopaths Podcast
🎤 The Naturopathic Nerd Podcast
📷 @julie.forrester.naturopath