Your circadian rhythm
determines the quality of your sleep.
Q: What is the “circadian rhythm?”
Answer: Your body keeping its own time, using its own internal clock mechanisms.
Your body’s internal clock system synchronizes itself to the world via several environmental signals.
primarily determine the quality of your circadian rhythm.
With few exceptions, all life developed “under bright days and dark nights” (source).
Melatonin is not unique to humans. It’s not unique to mammals. It’s in amphibians, birds, reptiles, cockroaches, insects, spiders, unicellular organisms, bacteria, plants – every plant that has been studied contains melatonin. Every organism contains melatoninRussel Reiter, PhD
These environmental signals (brightness & darkness) synchronize your body’s circadian clock.
More than any other variable, light drives your body clock.
— Much more than exercise, much more than the diet.
While your skin does have photoreceptors that sense environmental light — the eyes have 100x more photoreceptors than skin.
The eyes are the windows to the circadian soul.
The light in your environment — along with only a few other factors — holds the keys to mastery of your circadian rhythm.
Those other variables include:
- clean air & healthy buildings
- a calm mind
- meal timing
- gut health
— but light is circadian royalty. Nothing else, by itself, comes close.
Light, the Most Important
Environmental stimuli signaling the progression of time are known as zeitgeber, a German word meaning “time giver,” and include light as the most prominent signal, as well as others, such as patterns of exercise, food consumption, social activity, and more.https://journals.lww.com/cmj/Fulltext/2021/03200/Light_therapy__a_new_option_for_neurodegenerative.2.aspx
The most important zeitgeber (from German, something that “gives time”) reaching the SCN is ambient light in the environment.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6751071/
Light during the day and darkness at night are crucial factors for proper entrainment of the human circadian system to the solar 24-h day.https://pubmed.ncbi.nlm.nih.gov/28637029/
Melatonin is the hormone of sleep. It rises, you sleep. It falls, you are alert.
- Melatonin has all sorts of benefits: it’s anti-cancer, it promotes immunity, it’s anti-inflammatory, and protects the gut microbiome from pathogens.
In the modern world, melatonin cycles tend to be weak — and failing.
To promote sleep — and promote other benefits — melatonin must rise high in the evening and stay high all night.
But it’s not as simple as taking melatonin supplements.
No, in order to rise high at night, melatonin must be low all day.
It’s a cycle — without one, you can’t have the other.
Drops in the Morning
Low all day
Melatonin crashes in the morning — allowing you to wake up — releasing you from the powerful grip of drowsiness.
If melatonin stays high, you’ll keep sleeping, feel sluggish & groggy, and have trouble getting going.
Melatonin — Rises after Dark
High all night
Melatonin rises at nighttime, just before bed — forcing your body into both 1) wanting sleep, and 2) easily falling asleep.
Chronic disruptions of circadian rhythm may have the potential to seriously affect human health.
For instance, decrease of melatonin levels plays an important role in development of chronic diseases and conditions such as cancer 61, 80, 81, 82, 83, cardiovascular diseases 83, reproduction 84, endometriosis 84, gastrointestinal and digestive problems 85, diabetes 86, 87, obesity 88, depression 89, sleep deprivation 90, bipolar spectrum disorders 91, and cognitive impairment 92.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7065627/
How We Tell Solar Time
The body’s clock keeps time on its own, but it’s always receiving clues — from the environment — about the time of day.
There is a time, each day, called “solar noon.” This is when the sun is the highest in the sky, at any given location.
- Sunrise is when “daytime” begins
- Sunset is when “nighttime” begins
Research has confirmed — again and again — that a healthy circadian rhythm is one that aligns closely to natural sunlight cycles.
When the sun is up, it’s important that your eyes (and skin) see bright light.
And when the sun is down, it’s important that your eyes (and skin) see darkness.
A healthy melatonin cycle should align perfectly with natural sunlight cycles: when the sun is up –> melatonin is down.
The further our body’s cycle gets away from “solar time,” the worse the outcomes for our health.
How do we become out of sync with solar time?
- Sleeping in: Missing critical hours of sunlight each morning
- Bright light at night
- Staying indoors all day
- Staying up light
Staying in sync with solar time is an important foundation of longevity — it’s a methodology that is essential to maintaining proper melatonin levels: low in daytime, high at night.
Three types of light keep melatonin levels optimally healthy.
Let’s dive into the mystery and magic of light. Learn to master this most important circadian muse.
Enjoy the direct benefits of morning light.
- Do you want astronomical levels of healing for your circadian rhythm — and, therefore — entire body?
Bright morning light starts each day perfectly — no matter what happened yesterday.
There are three major reasons we need morning sunlight:
- Morning light suppresses morning melatonin — allowing you to wake up and start your day
- Morning light starts your circadian rhythm
- Morning light raises serotonin — which will be converted to melatonin at night
Without serotonin, melatonin cannot be produced at night — meaning your sleep will suffer.
Serotonin is an incredibly important hormone during the day, too — don’t be fooled by internet experts.
Without a habit of receiving your bright morning light, your other attempts to be healthy, lose weight, feel better — or sleep better — will only be playing catch up.
As we’ll prove, the sheer power of bright morning light — for your brain chemistry, hormones, metabolism, and future circadian rhythm — are nothing short of astounding.
You’ll notice, too, when you try this for yourself: The benefits of morning light are so great that nothing can replace it. No other hack can do what it does, and once you’ve missed morning light, it’s gone for today.
But you don’t have to miss it! Start receiving morning light — first thing tomorrow morning — and make it a life-long habit that never once regret.
Why should you decide to get morning light each day?
Let’s explore the science…
Natural light exposure — beginning with morning light — “rapidly” resets the circadian rhythm.
Further, we demonstrate that earlier circadian timing can be rapidly achieved through natural light exposure during a weekend spent camping.https://pubmed.ncbi.nlm.nih.gov/28162893/
Camping — which is spending 24 hours outdoors — shifts the circadian rhythm forward, aligning the modern body with solar time.
We also show that circadian and sleep timing occur earlier after spending a weekend camping in a summer natural light-dark cycle…
…compared to a typical weekend in the modern environment.https://pubmed.ncbi.nlm.nih.gov/28162893/
Morning light, by itself, directly stabilizes the circadian rhythm.
Our results indicate that bright blue-enriched morning light stabilizes circadian phase, and it could be an effective counterstrategy for poor lighting during the day and also light exposure at the wrong time, such as in the late evening.https://pubmed.ncbi.nlm.nih.gov/28637029/
Bright morning light lowers melatonin. Melatonin should be low in the morning.
The [morning] decline of melatonin levels was significantly greater after the exposure to [morning] blue-enriched white light.
Exposure to [morning] blue-enriched white light significantly improved subjective perception of alertness, mood, and visual comfort.https://pubmed.ncbi.nlm.nih.gov/30674951/