Why sleep is the most powerful free tool available to you
My son is four weeks old. He wakes when he's hungry and sleeps when he's full. No regard for the time, the darkness, or the pharmacist lying two feet away who will need to be behind a pharmacy counter in just a matter of hours.
Babies don't develop their circadian rhythm — the internal 24-hour clock that drives natural melatonin production and induces sleepiness — until around eight weeks old. Right now, he's running on pure survival instinct. No rules, no social contract, no alarm for him to be somewhere at 7am.
I'd be jealous if I wasn't so tired.
Sound familiar? Maybe not a newborn specifically — but the lying awake, the ceiling-staring, the to-do list in your mind playing on loop at midnight. You are acutely aware of the fact that each second unslept is a second closer to your workday starting. You run the mental arithmetic that if you were to fall asleep right now then you’d have precisely 4 hours 37 minutes and 22 seconds of sleep. There are no more sheep left to count.
You’re not alone. A 2024 survey of 15,000 UK adults found that 60% of us are sleeping on six hours or less per night. That’s three in five of us not meeting the recommended targets for sleep of 7 to 9 hours per night.
And here’s the uncomfortable bit; many people wear this as a badge of honour. As if hustle culture and being chronically stressed is a sign of the modern-day high achiever.
But as a pharmacist, I’ve seen the devastating long-term health impacts that chronic sleep deprivation can leave you with. Poor sleep catches up with you – maybe not tomorrow, or the next day, but one day.
Sleep is the single most powerful, free and accessible health intervention available to you. It outperforms every single supplement on the shelf. And most of us are not paying nearly enough attention or respect to it.
In my launch blog post, I laid out my six-item formulary for better health and longevity. Sleep was number one on that list. Not by accident – here’s why.
Why does sleep exist?
I’ve been thinking about this question a lot recently. Evolutionary theory states that natural selection weeds out traits that don’t confer survival or reproductive advantage. Being unalert or asleep is the ultimate vulnerability. Sleep leaves you exposed to attack. You are not foraging, protecting your young, or watching for predators. For essentially a third of your life on this planet you exist “offline”. Therefore, the fact that almost every species on earth performs this biological act of vulnerability suggests that it is of extreme importance.
The act of being asleep is not as inactive as scientific opinion once assumed. We now know that it is one of the most metabolically active periods in the day - hormone regulation, immune system reset, clearing of metabolic waste, and more.
People may say that they function perfectly well on five hours (and ungodly amounts of coffee) but they are definitely leaving metabolic health on the table. Undoubtedly, kicking the can down the road and building a sleep debt that will eventually have to be repaid.
Horlicks anyone?
What actually happens when you are asleep?
Did you know sleep runs in ~90-minute cycles? A healthy night typically includes four to six cycles.[1] Each stage has a distinct role ranging from muscle and DNA repair to memory consolidation. None of these processes can be replicated by supplements or “biohacks.”
Sleep quality depends on both duration and structure. It begins with non-REM sleep (the “dropping off” stage) where brain activity slows, heart rate falls, and muscles relax. You’re easily woken here, sometimes by that sudden “falling” sensation known as a hypnic jerk. To transition into deeper sleep, you body temperature must drop by ~1–1.5°C,[2] which is why sleeping in a slightly cooler room helps. Think of the air con you have blasting all night when you’re on your summer holidays.
Around 50% of total sleep is spent in the deeper non-REM stages (N2/N3). Despite appearing restful, your brain activity is lighting up. Key features of this stage include consolidation of memories and neural repair. This is also when the body performs most of its physical recovery by releasing growth hormone to repair tissues. This is the stage of sleep that I think of when patients feel constantly fatigued despite normal blood tests. The issue often comes back to poor sleep quality and failure to reach this restorative stage.
Sleep is critical for brain and immune health. During deep sleep, the brain clears metabolic waste via the glymphatic system. Poor or shortened sleep reduces this clearance, allowing harmful build-up of metabolic waste and proteins (e.g. amyloid plaques); a proposed contributor to dementia.[3]
The final stage, REM sleep, is where dreaming, emotional processing, and creativity peak. Procedural skills—like riding a bike or playing an instrument—are reinforced here. The body enters temporary paralysis to prevent you from acting out your dreams. REM sleep occurs at greater lengths in the second half of the night. Cut sleep short and you disproportionately lose REM compared to the other stages which leads to impaired emotional resilience, mental health, and performance.[4]
Your body clock controls everything
Humans are meant to be awake in the daylight and asleep during darkness. We are diurnal creatures. Our biology is wired to perform this way. That’s not up for debate.
Earlier I introduced you to the “circadian rhythm”. Every cell in your body runs off of this same 24-hour clock. When you are operating in alignment to this clock (awake in the day, asleep in the night) your body hums along. When it’s disrupted, things start to unravel. The brain is fantastically attuned to respond to light and dark signals from receptors in your eyes. The pineal gland then orchestrate the release of melatonin to induce sleepiness as the light fades.[5] Scrolling on screens, particularly screens which omit blue light, plays havoc on this natural process of sleepiness.
It is known that shift workers are at greater risk of many metabolic diseases and even early death. I have held consultations with countless shift workers who are struggling with fatigue, weight gain, poor hormonal health and mental health issues. They are acutely aware of all of this but lack the means or ability to change jobs.
I see the repeat prescriptions that come in for hypnotics and sleep medications for these patients who are left trying to induce daytime sleep artificially. Fighting a difficult battle since every cell in their body screams at them to stay awake whilst the sun is in the sky. Furthermore, The International Agency for Research on Cancer has classified night shift work as a probable carcinogen. Not a possible one. A probable one. That’s the same classification level as some industrial chemicals.[6]
Now, I’m not saying this to frighten anyone who works shifts. I’m saying it because it illustrates just how fundamental circadian alignment is to human health. If disrupting it by a few hours, a few nights a week, carries this level of risk, imagine what years of inconsistent and inadequate sleep does.
I’m a dad. I have been in the metaphorical sleep trenches. I am back there now with the recent birth of my son. My sleep is definitely not perfect. But I recognise this is just a season of life that I have to go through. The difference I feel the following day from a night of good sleep is obvious to me. The thing that I notice most is that I have less food noise which allows me to make better food choices. A period of good sleep will keep leptin (satiety hormone) high and ghrelin (hunger hormone) low. Sleeping well is the diet trick that most people are completely overlooking.
The Short-Sleeper Myth
I need to address this because someone will bring it up: “But some people only need four or five hours.” Yes. There is a genuine genetic variant — a mutation in the DEC2 gene — that allows a very small number of people to function well on significantly less sleep than the rest of us. The research suggests this accounts for fewer than two per cent of the population. Possibly fewer than one per cent.[7]
Let me put that differently. If you’re in a room of 100 people who all claim they’re fine on five hours, statistically one or two of them might actually be telling the truth. The other 98 have simply adapted to the feeling of being chronically underslept. They’ve forgotten what fully rested feels like. Their baseline has shifted so far that impaired feels normal.
What You Can Actually Do About It
Right. The bit you’ve been waiting for. If you’ve not already fallen asleep until this point then I am about to share some actionable sleep hygiene tips. Grounded in reality, spanning far beyond the generic advice of “turn off screens and drink chamomile tea” advice that you’ve heard a hundred times (Although I do love chamomile tea).
Most sleep advice is generic and incomplete. The development of sleep trackers (Oura ring, Whoop Band, etc.) are shifting this frame and allowing people to discover personalised insights into how they sleep. These devices are definitely useful but a word of warning - these devices are not suitable for everyone, particularly if you are likely to suffer from health anxiety or possess obsessive personality traits.
Some devices even attempt to wake people up as they are moving between sleep stages with the intention of minimizing the feeling of sleepiness at the point of waking. For people, who like me, feel these actions are a little over-the-top I want to give you the things that, in my clinical experience and based on the evidence, actually make a measurable difference without the need to spend hundreds of pounds on the latest tracker.
Fix your wake time before your bedtime. Most people try to improve their sleep by going to bed earlier. That’s backwards. Your body’s circadian rhythm anchors to when you wake up, not when you fall asleep. It is now believed that sleep consistency is just as important as sleep duration. Pick a wake time and stick to it — weekdays and weekends. Yes, even weekends. This is the single most impactful change most people can make, and it’s the one nobody wants to hear. *Reader weeps as they change their alarm settings to include weekend wake-up calls.*
Get bright light in your eyes within the first 30 minutes of waking. Not through a window. Not through sunglasses. Outside, facing the sky, even on an overcast day. Natural light in the morning suppresses melatonin and sets the clock for your cortisol awakening response.[5] It tells your brain: the day has started, start the 14–16 hour countdown to sleep. This is free, takes five to ten minutes, and the research behind it is robust. If you do nothing else from this post, do this.
Create a wind-down routine. Your brain cannot go from full speed to sleep in the time it takes to brush your teeth. It needs a wind-down period — ideally 30 to 60 minutes — where the stimulation drops. This doesn’t mean you have to meditate or journal. It means step away from work emails, stop doom-scrolling, and do something that doesn’t require your brain to be reactive. Read a book. Talk to your partner. Listen to something. The activity matters less than the reduction in cognitive load.
Temperature is more important than most people think. Your core body temperature needs to drop by, on average, more than one degree celsius to initiate sleep. Keep your bedroom cool (16–18°C) to make it an environment suitable for quality sleep. Counterintuitively, a warm bath or shower before bed actually helps here. The warm water draws blood to the surface of your skin, which then radiates heat and drops your core temperature faster once you get into bed.
Be honest about caffeine. I’m a pharmacist, so let me give you the pharmacokinetics: caffeine has a half-life of approximately five to six hours. Some people will be slow metabolizers of caffeine due to certain genetic polymorphisms and for these people the half-life will be even longer. That means if you drink a coffee at 3pm, roughly half of that caffeine is still in your system at 9pm. Contrary to popular belief, caffeine doesn’t actually give you energy. It blocks the chemical messenger (Adenosine) responsible for inducing sleepiness. Simply put, caffeine blocks the feeling of sleepiness.[8] Caffeine will also affect the time spent in deep non-REM sleep which as we’ve discovered is where the heavy repair work happens.
My general advice to patients: no coffee or energy drinks after midday if you’re serious about sleep quality. If that feels extreme, try it for two weeks and see what happens. I’ll never forget the teenage girl who came in complaining of headache and insomnia - turns out 6 large cans of red bull (900mg caffeine) per day isn’t the refreshment of choice for good quality sleep.
The Cost of Doing Nothing
I don’t want to end on a fearful note. That’s not my intention. This blog is meant to be empowering and give you the practical tools and confidence to go about making the changes necessary. But I do want to be honest with you, because I think you deserve honesty over comfort.
Chronic sleep deprivation is associated with an increased risk of cardiovascular disease, type 2 diabetes, obesity, depression, anxiety, weakened immune function, and faster cognitive decline.[9] A RAND Europe study found that regularly sleeping under six hours per night raises the risk of premature death by 13%. [10] Sleep deprivation is estimated to cost the UK economy billions in lost productivity each year. And behind those numbers are real people — people I see behind the counter, picking up prescriptions for conditions that might have looked very different if sleep had been taken seriously ten years earlier.
That’s the thing about sleep. The consequences of neglecting it are slow and cumulative. You don’t feel the damage today. You feel it in your forties, your fifties, your sixties — when the compound interest of decades of under slept nights starts showing up as medical diagnoses.
Start Tonight
You don’t need to overhaul your life. You need to pick one thing from this post and do it consistently for two weeks. Fix your wake time. Get outside in the morning. Move the coffee to before 1pm. Cool the bedroom down.
Prioritise your sleep and do it well. Everything else gets easier as a downstream consequence.
If this landed with you, sign up to the Dose of Longevity monthly newsletter. Every month you’ll get a deep dive on a health topic that matters, an honest debunk of a product or trend, and a short personal story from behind the pharmacy counter. No spam, no upselling, just evidence-based content from an NHS pharmacist who’d rather you didn’t need him.
www.dose-of-longevity.kit.com
Sleep tight,
Jake
Dose of Longevity
References
1. Patel AK, Reddy V, Shumway KR, Araujo JF. Physiology, Sleep Stages. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK526132/
2. Okamoto-Mizuno K, Mizuno K. Effects of thermal environment on sleep and circadian rhythm. J Physiol Anthropol. 2012;31(1):14. doi:10.1186/1880-6805-31-14
3. Nedergaard M, Goldman SA. Glymphatic failure as a final common pathway to dementia. Science. 2020;370(6512):50–56. doi:10.1126/science.abb8739
4. Walker MP, van der Helm E. Overnight therapy? The role of sleep in emotional brain processing. Psychol Bull. 2009;135(5):731–748. doi:10.1037/a0016570
5. Jung CM, Khalsa SBS, Scheer FAJL, Cajochen C, Lockley SW, Czeisler CA, et al. Acute effects of bright light exposure on cortisol levels. J Biol Rhythms. 2010;25(3):208–216. doi:10.1177/0748730410368413
6. International Agency for Research on Cancer. Night Shift Work. IARC Monogr Eval Carcinog Risks Hum. 2020;124:1–371. PMID: 33656825
7. He Y, Jones CR, Fujiki N, Xu Y, Guo B, Holder JL, et al. The transcriptional repressor DEC2 regulates sleep length in mammals. Science. 2009;325(5942):866–870. doi:10.1126/science.1174443
8. Nehlig A. Adenosine, caffeine, and sleep–wake regulation: state of the science and perspectives. J Caffeine Adenosine Res. 2022;12(3):105–116. doi:10.1089/caff.2022.0006
9. Itani O, Jike M, Watanabe N, Kaneita Y. Short sleep duration and health outcomes: a systematic review, meta-analysis, and meta-regression. Sleep Med. 2017;32:246–256. doi:10.1016/j.sleep.2016.08.006
10. Hafner M, Stepanek M, Taylor J, Troxel WM, van Stolk C. Why sleep matters—the economic costs of insufficient sleep: a cross-country comparative analysis. RAND Health Q. 2017;6(4):11. PMID: 28983434
