I Fixed My Diabetes But My Sleep Stayed Broken for 6 Months

Six months after stopping all my medications, I was still waking up at 3am every single night. My blood sugar was perfect. My sleep was not.

I’m Neil. I reversed my type 2 diabetes and stopped six medications, but nobody told me my sleep would be the last thing to heal.

In the next nine minutes: why metabolic damage breaks sleep patterns decades before diagnosis | the timeline my body actually followed | what finally changed at month seven. Here’s what happened in October 2023.

So why does this happen? You sort out the blood sugar. You stop the medications. Everything’s heading in the right direction. And yet you’re still lying awake at 3am wondering what on earth is going on.

Matthew Walker — neuroscientist at Berkeley, probably the world’s leading sleep researcher — puts it this way: sleep isn’t the third pillar of health. It’s the foundation everything else sits on. Exercise, nutrition, fasting — all of it rests on sleep. Which is a problem, because what Walker’s work also shows is that metabolic damage doesn’t just affect your blood sugar. It damages the system that controls when you sleep and how deeply you sleep. And that damage takes time to reverse. Longer, it turns out, than the blood sugar does.

Here’s the mechanism. And this is where it gets interesting.

Your body is a factory with shift workers, each on a precise rota. Your melatonin — the night security guard — is supposed to lock up at around 10pm, signal to your brain that it’s dark, it’s quiet, time to wind down. Your growth hormone repair crew clocks in between 11pm and 3am — that’s when the real overnight work happens, tissue repair, cellular maintenance, the stuff that makes you feel good the next morning. Your liver waste-processing team turns up at 2am. And your cortisol — the morning alarm — rings at 6am to get you up and ready.

Every worker has a schedule. And that schedule is timed to the light-dark cycle. To sunrise and sunset. To eating windows. To consistency.

Here’s what years of metabolic dysfunction does to that factory. Elevated blood sugar, insulin resistance, chronic inflammation — they don’t just sit in one place. They disrupt the whole signalling system. The night security guard starts clocking in late. The repair crew turns up but can’t do the work properly because the factory floor’s still noisy. Cortisol — which should be low at night — stays elevated. Result? You’re lying in bed at 3am, cortisol ticking over, brain running, unable to get back to sleep. Not because anything is wrong in that moment. Because the rota got scrambled years ago and it hasn’t been reset yet.

Dr. Sophie Bostock — sleep scientist and one of the leading researchers on behavioural approaches to insomnia — explains what this cortisol disruption actually does. When sleep is poor and cortisol stays elevated, your brain starts interpreting the world as threatening. Your threat perception goes up. Your stress response amplifies. Adrenaline, cortisol, blood pressure — all elevated, all reinforcing each other. It’s an evolutionary cascade that evolved to help you fight or flee. Useful if there’s a bear outside the tent. Not especially useful at 3am when you’ve had a perfectly fine day and you just want to sleep.

This matters for the person who hasn’t had a diagnosis yet as much as it does for the person who has. Circadian disruption doesn’t start at diagnosis. It develops quietly, often a decade or more before HbA1c flags anything. If you’re in your late thirties or forties, sleeping inconsistently, waking at odd hours, not feeling properly rested — the factory rota may already be slipping.

Now here’s the deep sleep piece. And this is the part most people miss completely.

Deep sleep isn’t just “good sleep.” It’s a completely different physiological state. All day, your brain accumulates rubbish. Dead cells, metabolic waste, damaged proteins — and specifically beta-amyloid plaques, which are linked to Alzheimer’s. During deep sleep — and only during deep sleep — your brain activates what’s called the glymphatic system. The council bin lorry. Drives through, collects the lot, hoses down the street. Walker’s team published research on this specifically: the glymphatic cleansing system only fully switches on during deep sleep.

Miss deep sleep — five-hour nights, broken sleep, alcohol before bed — and the lorry doesn’t come. Rubbish piles up. Not for a night. For weeks. Months. Which is why the question isn’t just “did you sleep long enough?” It’s “did you get enough deep sleep?” Two completely different questions.

And here’s what metabolic dysfunction specifically does to deep sleep. Elevated blood sugar disrupts slow-wave brain activity. Inflammation interferes with the glymphatic process. Poor insulin sensitivity affects melatonin timing. All of this means that even if you were putting in eight hours, the quality — the deep sleep percentage — was likely compromised for years before any blood test flagged a problem.

Which finally explains why fixing the blood sugar doesn’t immediately fix the sleep. The blood sugar is a relatively quick win — months, not years. The circadian factory rota, the cortisol rhythm, the deep sleep architecture — those are slower. The system has to relearn its schedule. And that takes time it is going to take regardless.

One misconception worth clearing up now: people assume fixing the diet means sleep follows automatically. I assumed the same. HbA1c sorted, medications stopped, thought sleep would be next. It wasn’t. Not for six months. That’s not a failure. That’s just biology running on different timelines for different systems.

So that’s the science. Here’s what it actually looked like from where I was standing.

October 2023. Boxing Day hasn’t arrived yet — I haven’t started the reset. But looking back at the data, sleep was already a mess. Four, five hours. Waking around 3am most nights. Not dramatically broken — not the kind of thing you’d take to a GP. Just not right. Lying there, cortisol presumably doing whatever elevated cortisol does at 3am, brain starting to tick. Nothing particular to think about. Just awake.

I’d been on cetirizine — daily antihistamine — for decades. What I didn’t fully clock at the time was that antihistamines have a sedating effect. So part of what I’d been experiencing as “going to sleep” wasn’t sleep architecture working properly. It was sedation. When I stopped the cetirizine, the actual picture became visible. Turns out it hadn’t been working properly for a long time.

Started the reset Boxing Day 2023. Fasting established February. Non-UPF eating locked in by March. HbA1c started moving. Measurements changing. Blood work improving. By April the direction was clear.

Sleep? Still broken. Still the 3am wake. Still that cortisol alarm going off at the wrong hour, like a factory security guard who’d been clocking in at midnight for years and hadn’t been told the rota changed.

Honestly — most frustrating part of the whole process. Everything else was responding. I felt better during the day. But I’d wake at 3am and lie there an hour, sometimes two, just waiting it out.

What the data showed during that period was exactly what Sophie Bostock describes. Four consecutive nights under five hours — logged this during a heavy work week in spring 2024 — and the downstream effects were precise and entirely predictable. Cortisol elevated. Decision-making tanked. Ended up eating around 2,000 calories of sugary food in a single afternoon. Not because I was hungry in any meaningful sense. Because the brain, running on elevated cortisol and disrupted ghrelin, bypassed conscious decision-making entirely and went straight for quick fuel. (WMTWL-EVID-134)

Interesting thing about that data point: weight held steady. The metabolic flexibility I’d been building for ten weeks absorbed the wobble. But the sleep deprivation didn’t negotiate. It didn’t ask permission. It just did what disrupted cortisol and ghrelin do.

The shift came — and I’m being specific because the timeline matters — around month seven. May 2024.

Three months off antihistamines. Circadian discipline had been building steadily — consistent 10pm bedtime, room at 17 degrees, no screens after 8pm, eating window closing by 7pm. Eighteen-six fasting settled and comfortable.

One morning in May I woke up at 5:47am. No alarm. Room pitch black. No grogginess, no reaching for the phone to calculate how many minutes I could still squeeze. Just clear. Ready. Awake. (WMTWL-MOM-005)

Hadn’t happened since my twenties.

What I understand now is that this wasn’t sleep “getting better” in any simple sense. The factory rota had finally reset. Cortisol was doing what cortisol is supposed to do — low at night, rising naturally toward 6am. Melatonin timing corrected. The repair crew had been doing their work. I just couldn’t see it from inside the process.

The year-end data backs it up. Tracked sleep quality across all of 2025. Fifty-seven nights rated nine or ten out of ten. No sleeping pills. No melatonin supplements. No alcohol to “relax.” Just metabolic health, circadian discipline, and enough time for the system to rebuild itself. (WMTWL-3315)

The sleep didn’t fix because I got healthy. It fixed because the underlying system — the factory, the rota, the circadian clock — had enough time and enough correct signals to rebuild. And that took the time it was always going to take.

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NHS blood tests going back to 2012 — the actual numbers, the GP conversations, what changed and what didn’t. If you want to follow someone who documents this properly rather than just talks about it, that’s what this channel is. Subscribe if that’s useful to you.

If any of this is landing — waking at odd hours, never quite rested, sleeping enough on paper but not feeling it — here’s where to start. One thing. Morning light.

Not a supplement. Not a device. Outside. Ten to fifteen minutes, within an hour of waking, without sunglasses.

Prof. Debra Skene at Surrey — one of the world’s leading circadian biologists — measured outdoor daylight against indoor artificial light. Even on a grey British winter morning, outdoor light is 100 to 500 times brighter than the strongest artificial lighting indoors. Your master body clock — the suprachiasmatic nucleus in the brain — is calibrated to that signal. It needs the short-wavelength light hitting the retina to know what time it is and set the day’s rota accordingly.

Without that morning signal, the factory workers drift. They start arriving at the wrong times. The rota slips a little every day, and the downstream effects — melatonin timing, cortisol rhythm, deep sleep quality — all shift with it.

Think of it like an analogue watch that loses two or three minutes a day. Left unchecked, it’s twenty minutes slow within a week. Morning light is resetting it against the correct signal every morning. Simple, free, ten minutes.

Practically: alarm goes, put something on, step outside. Ten minutes minimum. No sunglasses — they filter the specific wavelengths the clock needs. Overcast is fine. November in Yorkshire is fine. Outside is what matters, not sunshine.

Track it simply. Notepad by the bed. Write down the time you wake naturally if you do, and your morning energy out of ten. After two weeks you’ll have a pattern. Most people notice the first shift — waking more naturally, morning grogginess easing — within ten to fourteen days.

Start here before changing anything else. The factory rota resets from the morning signal first. Everything downstream follows that anchor.

One safety note: certain medications cause light sensitivity — some antibiotics, some blood pressure medications. If you’re on anything like this, check with your GP before spending extended time outdoors. Ten minutes is generally fine for most people, but worth knowing.

Timeline: be honest with yourself. My 3am wake pattern took six months to fully resolve. Morning light isn’t a quick fix. It’s the correct lever, applied consistently, over enough time for the biology to respond. Weeks for early signs. Months for the full reset. That’s the timeline.

I’ve built a sleep and circadian reset tracker — logs morning light practice, wake time, sleep quality, gives you a weekly trend. Link in description. Free.

Now the disclaimer — and I mean this every time.

Everything here is educational content, not medical advice. If you’re on medication — blood pressure, blood sugar, anything affecting your nervous system — speak to your GP before changing your sleep schedule or fasting pattern. Circadian interventions are generally low risk, but your specific history matters.

All of my results were self-monitored with regular GP reviews. The timeline I’ve described is mine. N equals one. Your biology runs on its own schedule.