SLEEP

WHAT IS ACTUALLY KEEPING YOU AWAKE?

You've all heard it before, have a cool, dark room, and no screens before bed. Many of you have tried it but you still lie awake, or fall asleep fine and wake at 2am wired for no reason.

That's because sleep is the end result of several physiological systems lining up at once - brainwave state, neurotransmitter availability, gut function, core temperature, blood sugar, and hormonal signalling, not just something that happens when you collapse into bed each night.

Here's what's actually going on underneath the standard vague advice.

Screen Time: a Brainwave Problem, Not Just a Blue Light Problem

The blue light story is true but incomplete. Blue light suppresses melatonin secretion. That's mechanism one. Mechanism two, and the one nobody talks about, is brain arousal.

Falling asleep is a descent through brainwave frequencies. You start the evening in Beta Waves, the frequency of active thinking and focused attention. As you wind down, that shifts to Alpha Waves, where you are awake but calm, then Theta Waves as you drift toward sleep onset, then Delta Waves as you drop into deep sleep. Each step down represents the brain reducing its own arousal.

This is where what you're watching and consuming really matters. Watching a TV show that is high action, tension, threat, conflict or high emotional stakes, crime, death, explosions, doesn't just keep you "engaged." It keeps Beta waves elevated because the show is designed to hold arousal, which is the opposite of what needs to happen for sleep onset. You can turn the screen brightness down, or wear blue-blocking glasses but you’ll still be neurologically wide awake.

Social media adds a second layer on top of arousal, reward-seeking. These platforms are built around the same reward schedule used in gambling research, where unpredictable rewards produce a stronger and more persistent dopamine response than predictable ones. Studies show that heavier social app use correlates with increased dopamine. Dopamine, along with cortisol and norepinephrine, works directly against melatonin's calming signal. So while you think you're just distracting yourself before bed or winding down, you're chemically priming yourself for pursuit and reward, which is the exact opposite of what you need.

The practical implication isn't "no screens." It's what you consume in the hour before bed needs to be low-arousal in both content and reward structure.

STRESS AND BrainwaveS: WIRED BUT EXHAUSTED IS A PHYSIOLOGICAL STATE

Screens aren't the only thing keeping people in an alert brain state. For a lot of clients, the bigger driver is that they never switch off.

As mentioned above, falling asleep means moving down through brain wave states, from alert, to calm, to drowsy, to asleep. People carrying chronic stress often can't complete that shift. Their brain stays stuck in the same alert pattern it was running at 3pm, which is why they can be exhausted and still lying there wide awake at 11pm.

Cortisol works the same way. It's meant to be high in the morning and steadily drop through the day, hitting its lowest point around bedtime. Chronic stress flattens or flips that pattern, so cortisol stays elevated in the evening instead of dropping, which keeps the nervous system running in the same alert state cortisol is meant to be winding down.

Worrying about not sleeping adds to the same problem, since worry itself is a stressor that keeps the system activated. A bedtime routine on its own won't shift a nervous system that's been running hot all day. You need to learn to calm it down has to happen across the day, not just in the hour before bed.

Nutrition: The Micronutrients Melatonin Actually Needs

Magnesium gets all the attention and it's not wrong, but it's one part of a longer pathway. Melatonin isn't made from nothing. It's the end product of a conversion chain starting with the amino acid tryptophan, and every step in that chain has a nutrient cofactor requirement.

The pathway runs:

Tryptophan → 5-HTP → Serotonin → N-acetylserotonin → Melatonin

• Turning dietary tryptophan into a usable form requires adequate stomach acid plus Zinc, B1 and B6.

• Tryptophan → 5-HTP requires Iron and Vitamin D.

• 5-HTP → Serotonin requires Vitamin B6, Folate, Vitamin C, B5, Magnesium and Calcium.

• Serotonin → N-acetylserotonin requires Zinc and Magnesium.

• N-acetylserotonin → Melatonin requires Folate, Vitamin B12 and Magnesium.

So a client who is "doing everything right" for sleep but is low in Iron, Zinc, Magnesium, B6 or Folate is still going to struggle, because the raw material for Melatonin production is short at multiple points in the chain, not just one.

Iron deserves its own mention beyond this pathway, because of restless legs syndrome. For someone reporting an urge to move their legs at night or unrefreshing sleep despite adequate hours, iron status is worth investigating specifically, not just as a general fatigue marker.

Gut Health: Where Most of Your Serotonin Actually Comes From

Over 90% of the body's serotonin is produced in the gut, not the brain, with a direct contribution from gut bacteria. The gut is also the largest source of Melatonin. Gut function isn't peripheral to sleep, it's a primary production site for the molecules that regulate it.

Several mechanisms link poor gut health to poor sleep:

Serotonin and tryptophan metabolism. Gut microbiota directly influence how much tryptophan gets directed toward serotonin production versus other metabolic pathways.

GABA production. Certain gut bacteria, including Lactobacillus and Bifidobacterium species, carry the enzyme that produces GABA, the primary neurotransmitter responsible for calming neural activity. Depleting these bacteria measurably lowers GABA availability.

The vagal and HRV connection. The Vagus nerve is the primary communication line between gut and brain, and it's heavily involved in parasympathetic (rest-and-digest) tone. Reduced heart rate variability, a marker of poor parasympathetic function, is consistently seen in both insomnia and obstructive sleep apnea. Gut issues like dysbiosis don't just affect digestion, they can blunt the parasympathetic shift needed to actually stay asleep through the night.

This is a two-way relationship, not gut-to-sleep only. Circadian disruption itself changes the microbiome, and a disrupted microbiome further impairs sleep, which is why poor sleepers with gut symptoms often don't resolve either issue by addressing just one.

Core Body Temperature: The Signal Your Body Waits For

Sleep onset is triggered by a drop in core body temperature, and that drop is driven by a specific mechanism, vasodilation at the extremities. As blood vessels in the hands and feet widen, heat moves from the body's core out to the skin, and from there dissipates into the surrounding environment. This turns out to be a stronger predictor of how quickly someone falls asleep than core temperature itself, heart rate, melatonin onset, or subjective sleepiness.

In controlled experiments, warming the skin at the extremities by less than one degree Celsius reduced sleep-onset latency by around 26%. This is the actual mechanism behind "warm bath before bed" advice, and it also explains why insomnia is often accompanied by cold hands and feet at night. Poor sleepers frequently show a blunted or absent rise in distal skin temperature, meaning the heat-dissipation signal that should be telling the brain "time to sleep" never properly fires.

A warm shower or bath 1-2 hours before bed drives peripheral vasodilation, and the subsequent cooling as you get out mimics the natural pre-sleep temperature drop. Evening aerobic exercise has a similar effect, raising temperature acutely and producing a cooling rebound afterward that can improve sleep onset, provided it's not too close to bedtime or intense. Consistently cold hands and feet at night, especially in people with low iron or thyroid dysfunction, both of which impair peripheral circulation, is worth flagging as a contributing factor rather than dismissing as unrelated.

Blood Sugar: Stability and Night Waking

Waking consistently in the early hours, particularly the 2-4am window, is often linked to stress or "light sleep," but blood glucose regulation could also be a trigger.

When plasma glucose falls, the body has a hormonal response involving adrenaline, cortisol, glucagon and growth hormone. Studies inducing a glucose drop during sleep found this response is enough to wake healthy adults from sleep, with plasma adrenaline rising sharply in the minutes immediately after waking. The awakening response is the sympathetic nervous system firing to correct a falling glucose level, which is a protective mechanism, but one that fragments sleep when triggered nightly.

For clients eating minimally in the evening, skipping dinner, going long stretches without adequate carbohydrate or protein at their last meal, or drinking alcohol close to bedtime (which stops the liver from making enough blood sugar overnight), this is a possible cause behind consistent 2-4am wake-ups. It's a common pattern in people with erratic or restrictive eating, where evening intake is often the first thing cut.

Hormonal Shifts: Progesterone, GABA and Midlife Sleep Disruption

For women in perimenopause and beyond, sleep disruption is frequently framed as an unavoidable symptom rather than something with an identifiable mechanism. Progesterone is part of that mechanism.

As progesterone production becomes erratic in perimenopause and then declines, it converts in the brain to less allopregnanolone, a compound that calms the nervous system by boosting GABA activity, the same pathway that drugs like Valium target. As allopregnanolone falls, the brain loses a source of GABA support it has relied on for decades. This shows up as reduced deep sleep, more fragmented sleep, and the 2am-wide-awake pattern many women in this life stage describe. Declining estrogen compounds this with its effect on REM sleep.

The purpose of this article isn't for you to learn or necessarily understand all of this, but what I want you to understand is that if your sleep quality is poor and your only focus is only to stop doom scrolling at night, you could be missing a bigger underlying problem.

No system operates in isolation.

A person with low iron is compromised on melatonin synthesis, RLS risk, and peripheral circulation for thermoregulation, all at once.
A client under-eating in the evening is disrupting blood glucose stability while also cutting the nutrients needed for serotonin and melatonin production.

Sleep quality is a mix of how well several systems are working together, which is exactly why generic advice rarely works.