WRITTEN BY Frederick W. Sabido, MBA; Editor: Frederick L.H. Sabido, MD, FACS
Welcome to The Wellness Ledger
A weekly health led newsletter grounded in evidence-based medicine along with prospective randomized controlled trials by medical specialists. Our goal is to help you make sense of complex scientific information and turn it into clear, evidenced based practices you can use to make better decisions about your health and wellness.
Last year, eight people spent a week camping in the Rocky Mountains.
No phones. No electricity. No artificial light of any kind. Just sunlight by day and a campfire at night.
When they came back, researchers checked their melatonin levels. Every single participant's biological clock had shifted forward by almost two full hours. They were getting drowsy earlier. Waking earlier. Feeling sharper in the mornings.
The researchers had not given them any medication. Had not changed their diet. Had not taught them any breathing techniques.
All that changed was the light.
That study, published in Current Biology by Wright and colleagues in 2013, is one of the most clarifying things in sleep science. It suggests that most people are not broken sleepers. They are living in lighting conditions their biology was never built for.
Here is what is actually happening inside your brain, and what the evidence says you can do about it.
TL;DR | MEDICAL TREND SNAPSHOT
EMERGING STUDY: MUSCLES HAVE THEIR OWN CLOCKS
A 2025 study from Northwestern University found that skeletal muscle stem cells carry an internal circadian rhythm. Mice injured during their active phase healed significantly faster than those injured during rest.
What this might mean: when you exercise and when you recover could matter as much as the training itself.
What it does not yet prove: this is animal data. Whether shifting your workout time will produce measurably faster muscle repair in free-living humans has not been tested in a proper clinical trial.
Source: Peek et al., Science Advances, 2025
TRENDING CLAIM: MOUTH TAPING
Mouth taping at night is supposed to force nasal breathing, boost nitric oxide production, and improve sleep. A 2024 systematic review in PLOS One found no solid clinical evidence for any of these benefits.
In people with undiagnosed sleep apnea or nasal obstruction, taping the mouth shut at night creates a genuine risk of oxygen deprivation.
This trend has collected wellness language. It has not collected clinical data.
MISUNDERSTOOD SCIENCE: SLEEPING IN DOES NOT HELP
Sleeping until 11 AM on Saturday does not recover your sleep debt. It moves your body clock backward. Your brain reads late morning light as the start of your day and shifts your entire biological schedule later.
By Monday, your alarm fires at what your body still reads as deep night. Researchers call this social jet lag.
You are not recovering. You are creating a new problem every single weekend.
THE BIOLOGY | HOW YOUR CLOCK GETS SET
There are about 20,000 neurons sitting just above the point where your optic nerves cross.
They are called the suprachiasmatic nucleus, or SCN.
They do not process images. They do not handle memory. Their only job is to know what time it is.
Here is the strange part: the SCN runs slightly long. Its natural cycle is about 24.2 hours. Left without any cues, it drifts. You would wake up later and later each day, like flying west forever with no destination.
What calibrates it is light. Specifically, a set of cells in your retina that have nothing to do with vision. They contain a photopigment called melanopsin and they wire directly to the SCN. When they detect bright light, they fire a single message upstream: it is daytime. The SCN resets its clock. Cortisol rises. Melatonin production stops. Body temperature starts to climb.
This happens every morning. It is supposed to happen every morning.
The problem is that these same cells respond to your living room lamp at 11 PM.
They peak at around 480 nanometers, aka the blue end of the visible spectrum.
It is also exactly where LED lighting peaks.
HOW MELATONIN ACTUALLY WORKS
Melatonin is not a sleeping pill. It is a timing signal.
Think of it as the biological equivalent of dimming the house lights before a show. The show (sleep) does not start the moment the lights go down. But without the signal, the show does not start on time.
When artificial light delays melatonin onset by 90 minutes, your body keeps treating 11 PM like it is still 9:30 PM. You feel wired. You scroll again. You wonder why you cannot wind down. Nothing is wrong with you. Your body is waiting for a signal that the light is preventing it from receiving.
HOW THE MOLECULAR CLOCK WORKS (in plain language)
Inside every cell in your body, two proteins called CLOCK and BMAL1 switch on genes that slowly build up a pair of inhibitor proteins across the day. By evening, so many inhibitors have accumulated that they block the very genes that made them. Overnight, the inhibitors break down. By morning, the genes switch on again.
This loop takes almost exactly 24 hours. That is why it is called circadian, from the Latin for 'about a day.'
This cycle is running right now in your liver, your pancreas, your muscle cells, and your skin. It is not just in your brain.
THE EVIDENCE | THREE THINGS BREAKING YOUR RHYTHM
The research points to three main disruptors. The evidence on each is different, and that difference matters.
1. Artificial Light at Night
Gooley et al. at Harvard (2011, PMID 21193540) exposed 116 healthy adults aged 18 to 30 to standard room light, under 200 lux, in the hours before bed for five consecutive days.
What is 200 lux? The light in a typical living room. Nothing dramatic.
Melatonin onset was delayed in 99% of participants, by an average of 90 minutes. When participants slept under room light, melatonin was suppressed by more than 50% in 85% of trials.
WAIT: ARE BLUE-LIGHT GLASSES THE ANSWER?
A lot of people buy blue-light-blocking glasses to fix this. A 2023 Cochrane review (Singh et al., PMID 37593770, multiple RCTs) found no clinically significant improvement in total sleep time or sleep quality from these lenses.
The SCN responds to total brightness, not just wavelength. Filtering blue out of a bright screen while sitting under bright ceiling lights is like wearing sunscreen inside a tanning bed.
The overhead room light is the problem. Not the phone.
2. Social Jet Lag
In 2006, chronobiologist Till Roenneberg gave a name to something most people experience but had never measured (Wittmann et al., Chronobiology International, PMID 16648550, n=501). Social jet lag is the gap between when your biology wants to sleep and when your schedule forces you to.
Around 70% of working adults experience at least one hour of it every week.
A 2014 cohort study tracked 145 healthy adults (Rutters et al., Journal of Biological Rhythms, PMID 25252710). People with two or more hours of social jet lag had higher resting heart rates, elevated morning cortisol, and higher rates of metabolic syndrome.
No diet differences. No exercise differences. Just the weekly clock shift.
3. Late Eating
Your liver, pancreas, and gut each run their own molecular clocks, and food is what sets them. When food arrives, these organs read it as beginning to proceed with your bodily function.
Eat a large meal at 11 PM and your liver thinks it is noon. Your SCN knows it is night. Two systems, opposite schedules. The result is worse insulin response, impaired glucose clearance, disrupted lipid processing.
Garaulet et al. (2013, International Journal of Obesity, PMID 23357955) followed 420 overweight adults for 20 weeks. Two groups: early eaters and late eaters, defined by when they ate their main meal.
Same calories. Same food. Same exercise.
Early eaters lost 9.9 kg. Late eaters lost 7.7 kg.
2.2 kg of difference. From timing alone.
THE PROTOCOL | WHAT THE EVIDENCE SUPPORTS
Most sleep advice fails because it focuses on evening habits while ignoring the intervention with the strongest evidence: morning light.
Here is what the clinical record actually supports, built into five daily steps.
MORNING: WITHIN 1 HOUR OF WAKING UP
Go outside for 10 to 20 minutes.
Wright et al. (2013) replaced indoor electrical lighting with natural sunlight for one week. Every participant's clock advanced by close to two hours. Sleep inertia in the morning dropped significantly. The reason: outdoor light delivers 10,000 to 100,000 lux. Your SCN reads indoor lighting at 300 to 500 lux as dim. Window glass cuts outdoor lux by up to 50 times, so sitting by your kitchen window does not count.
Wright et al., Current Biology, 2013, PMID 23910656
DAYTIME: PICK AN EATING CUT-OFF
Stop eating by early evening. A 10-hour daylight window works for most schedules.
Wilkinson et al. (2020) tracked 19 adults with metabolic syndrome for 12 weeks. Participants limited all eating to a 10-hour window with no calorie counting and no dietary restrictions. At the end: lower body weight, less visceral fat, lower blood pressure, improved lipid panel. Honest caveat: participants ate about 8% less incidentally. Whether the benefit is purely circadian or partly from that small calorie reduction is an open question. The direction of the evidence is clear.
Wilkinson et al., Cell Metabolism, 2020, PMID 31813824
EVENING: TURN OFF THE OVERHEAD LIGHTS
Replace ceiling lights with floor or desk lamps. Start 2 hours before bed.
Chellappa et al. (2011, PMID 21298068) compared cool-toned light at 6500K versus warm-toned light at 2500K at the same lux level. The cooler light suppressed melatonin significantly more. Important practical note: your overhead ceiling light at 200 lux causes more circadian damage than your phone screen at 50 lux, because of the angle and total irradiance reaching your eyes. Fix the room first. Then worry about the screen.
Chellappa et al., PLoS One, 2011, PMID 21298068
90 MINUTES BEFORE BED: WARM SHOWER
Shower at 40 degrees Celsius for 10 to 15 minutes. Then into a cool bedroom.
Haghayegh et al. (2019) synthesized 17 studies on passive body heating before sleep. Warm water at 40 to 42.5 degrees Celsius, used 1 to 2 hours before bed, reduced time to fall asleep by an average of 10 minutes. The mechanism: the warm water dilates blood vessels near the skin, pushing heat out of the body core. Core temperature drops. The hypothalamus reads that drop as a signal to begin sleep. The timing matters. Immediately before bed and the core has not cooled yet, which makes falling asleep harder, not easier.
Haghayegh et al., Sleep Medicine Reviews, 2019, PMID 31102877
EVERY DAY: SAME WAKE TIME
Same alarm, same time, every morning. Including weekends.
Phillips et al. (2017, PMID 28607474) monitored 61 students for 30 days using a Sleep Regularity Index. Irregular sleepers showed a melatonin onset delayed by an average of 2 hours and 36 minutes. They also scored measurably worse on cognitive tests. Wake time matters more than bedtime for circadian entrainment. Bedtime drifts with tiredness. Wake time is the fixed anchor the SCN uses to calibrate its phase.
Phillips et al., Scientific Reports, 2017, PMID 28607474
WHAT THE SCIENCE CANNOT YET TELL US
HONEST LIMITS OF THE RESEARCH
Lab vs. real life: Every gold-standard circadian trial uses windowless rooms, identical timed meals, and continuous monitoring. That environment eliminates the exact factors that cause real-world disruption. The gap between what works in a sleep lab and what works in a busy household is honest and large.
Chronotype matters: Some people's clocks genuinely run late. Forcing a true night owl to wake at 5:30 AM without simultaneous aggressive morning light therapy does not advance their clock. It just shortens their sleep.
On supplements: Melatonin works as a timing agent at 0.3 to 0.5 mg taken 3 to 4 hours before intended sleep. The 5 to 10 mg doses in most pharmacy products were designed to cause drowsiness and give that feeling of sleepiness, not to shift the clock. That is a different mechanism with no solid evidence for circadian alignment.
Magnesium and L-theanine: No gold-standard polysomnographic trial data show a meaningful effect on sleep architecture to this point. The evidence is not limited. It is essentially absent. You cannot supplement your way out of a broken clock. While supplements can be an aid and have beneficial factors outside the scope of trials, the root cause must be dealt with primarily.
READER'S PULSE
Before reading this: what did you think was the most important sleep habit?
This newsletter is for informational purposes only and does not constitute medical advice. Anyone with a diagnosed sleep disorder should work with a board-certified physician or sleep specialist.
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