Tired All Day, Wired at Night: The Six Systems Behind Broken Sleep
Poor sleep is rarely one bad habit — it is usually several biological systems drifting out of sync at once: circadian rhythm, nervous system tone, blood sugar, hormones, inflammation and nutrient status. Mark Hyman walks through the most common sleep questions and explains what the body is signalling behind each one. The practical core is small and consistent: morning light, a protein-and-fat dinner, less alcohol, a steady sleep window and magnesium.
Overview
This office-hours session reframes sleep trouble as a systems problem rather than a willpower problem. Hyman describes six overlapping drivers: a disrupted circadian clock, a nervous system stuck in the 'on' position, unstable blood sugar overnight, hormone imbalance across cortisol, melatonin, sex hormones and thyroid, chronic inflammation, and widespread nutrient depletion.
He explains the 'tired and wired' pattern — physically exhausted, mentally alert — as the signature of high cortisol meeting a body that never learned to downshift. The 2-to-4 a.m. waking so many people report is usually metabolic or hormonal: a nighttime blood sugar dip, an early cortisol rise, alcohol fragmenting sleep architecture, or perimenopausal shifts. Sleeping a full eight hours and still waking exhausted points instead to sleep quality — too little deep and REM sleep, inflammation, undetected breathing problems, or low iron, B12 and thyroid function.
On supplements, he places magnesium first, then L-theanine and glycine, with low-dose melatonin reserved for short-term circadian resets like jet lag. The closing frame is five pillars — light exposure, blood sugar stability, nervous system regulation, hormone balance and consistency — with the reminder that great sleep starts the moment you wake up, not when your head hits the pillow.
Key quotes
5You might feel exhausted, but your brain stays alert. That's why so many people feel tired all day and wired at night.
Sleep isn't something you force, it's something that happens when the body feels supported and safe.
Stress happens, relaxation doesn't. It takes deliberate effort to turn on your relaxation system.
If you wake up in the middle of the night, it's often metabolic or hormonal, not a personal failure.
They're called supplements, not replacements.
Key ideas
9The internal clock sets the whole night
The body runs on a clock guided by light, darkness and consistent timing. Late nights, screens, irregular schedules and missing morning light make sleep harder both to start and to sustain.
An overactive nervous system blocks sleep
When the body stays in a stress response with high cortisol and adrenaline, it does not feel safe to power down. The result is physical exhaustion paired with mental alertness.
Overnight blood sugar dips wake you up
If glucose drops in the night, the body treats it as an emergency and releases stress hormones to bring it back up. Blood sugar normalises, but cortisol is high and you are wide awake.
Hormones decide sleep depth, not just sleep onset
Cortisol, melatonin, progesterone, estrogen and thyroid all shape when you feel sleepy, how deeply you sleep and how rested you wake. These shift through perimenopause, menopause and chronic stress.
Inflammation reaches the brain and sleep with it
Brain dysfunction of almost every kind is linked to inflammation, and sleep disruption belongs on that list. Toxins, allergens, infections, microbiome changes, an inflammatory diet and stress all feed it.
Nutrient depletion is far more common than assumed
In Function's testing population, roughly 70 percent show a deficiency at the level considered a deficiency disease. Around 45 percent are low in magnesium, and low ferritin is one of the hidden drivers of insomnia.
The zebra discharges stress; we carry it
Drawing on Sapolsky's Why Zebras Don't Get Ulcers, Hyman describes zebras running from a lion, discharging the stress and then grazing calmly nearby. Humans stay in the chronic version and never complete the cycle.
Light and inconsistent timing confuse the clock
Blue light, evening screens and late mental stimulation suppress melatonin and signal daytime. Going to bed and waking at different times, especially on weekends, leaves the body unsure when sleep is due.
Eight hours in bed is not the same as recovery
Without enough deep and REM sleep, the repair, hormone regulation and memory consolidation never happen. Fragmented or shallow sleep, inflammation, breathing issues and low iron or B12 all leave you unrefreshed.
Practical takeaways
7- 1
Anchor a fixed sleep window 15:40
Pick a bedtime and wake time and hold them — 10 and 6, 9 and 5, 11 and 7, whichever fits your life. Keep it on weekends too, because consistency is what the clock actually reads.
- 2
Get outside within an hour of waking 16:00
Aim for at least 15 minutes of morning light, cloudy days included, without sunglasses. This is the single strongest signal for resetting the circadian rhythm.
- 3
Build a real downshift ritual 16:40
Breath work, stretching, gentle yoga, a hot bath with Epsom salt and lavender — all of these lower the stress response. Relaxation has to be practised deliberately; stress arrives on its own.
- 4
Make dinner protein-and-fat forward 18:10
A carb-heavy, sugar-heavy evening sets up the overnight crash that wakes you at 2 a.m. Balance starches with protein, fat and fibre, and skip sugar close to bed.
- 5
Move alcohol away from bedtime — or out 18:00
Even small amounts fragment sleep architecture and trigger early-morning waking. Leave at least four hours before bed, and try a stretch without it to see how mornings change.
- 6
Start with magnesium before stacking anything 22:40
Magnesium glycinate or threonate at night is the most consistently useful option, with L-theanine for a racing mind and glycine for deeper rest. Low-dose melatonin is for short-term resets like jet lag, not a nightly habit.
- 7
Track trends and check the basics 20:40
Look at sleep patterns across weeks rather than judging one night. If exhaustion persists, look at nasal congestion, allergies, and markers like iron, ferritin, B12 and thyroid.
Topics & chapters
15Why good sleep feels out of reach
Time in bed is not the same as rested. The problem is usually quality, not duration.
Circadian rhythm disruption
Light, darkness and consistent timing run the internal clock. When they drift, sleep gets harder to start and to hold.
The nervous system stuck on
High cortisol and adrenaline keep the brain alert even when the body is spent. This is the tired-and-wired pattern.
Unstable blood sugar overnight
A nighttime glucose dip triggers stress hormones. Cortisol rises, the mind races, and sleep is gone.
Hormones and sleep quality
Cortisol, melatonin, progesterone, estrogen and thyroid form a balance that decides how deeply you rest.
Inflammation as a hidden driver
Diet, toxins, infections and microbiome changes fuel inflammation, and inflammation disturbs sleep architecture.
Nutrient depletion
Magnesium, iron and ferritin, B vitamins and omega-3s all shape nervous system function and sleep.
Why you can't fall asleep when you're tired
The body is done but the mind will not switch off. Modern life keeps the stress system permanently engaged.
Chronic stress and the zebra story
Animals discharge acute stress and return to calm. Humans stay in the chronic version and never reset.
Blue light, screens and inconsistent timing
Evening light suppresses melatonin and signals daytime. Irregular schedules confuse the clock further.
What actually helps you fall asleep
A fixed sleep window, morning sunlight, an evening downshift ritual and magnesium at night.
Waking between 2 and 4 a.m.
The most common question of all. Usually blood sugar, an early cortisol rise, alcohol or hormone shifts.
Eight hours and still exhausted
Too little deep and REM sleep, inflammation, breathing problems or nutrient gaps leave you unrestored.
Which supplements actually help
Magnesium first, then L-theanine and glycine. Low-dose melatonin only short-term, and no random stacking.
The five pillars and quick wins
Light, blood sugar, nervous system, hormones and consistency — with morning sun and a protein dinner as the fastest starting points.