Sleep: The Thing You're Probably Getting Wrong Even If You Think You're Getting It Right

I used to be proud of burning the midnight oil.

There was something satisfying about being the last one awake, getting things done while the world was quiet. I'd push late into the night and then try to catch up in the morning. Sometimes it worked. Most times it didn't. But I kept doing it because I had energy to push with, or at least I thought I did.

It turns out I was chronically sleep deprived for most of my adult life without realising it. The clue came after I got married. My wife, who grew up in Argentina where the afternoon siesta is just part of life, suggested I lie down with her in the afternoon. I thought it was unnecessary. I wasn't tired. I didn't need it.

I'd be asleep within minutes and wake up three hours later.

Every single time.

That's not a nap. That's a body that has been running on a deficit for so long it stopped sending the signals properly. I had pushed through exhaustion for years using willpower and habit, and my body had simply adapted to the deprivation. Once I started catching up, the mid-morning dopiness and the mid-afternoon slump started to lift. It didn't fix my deeper energy issues, that came later, but it was the first sign that sleep was something I had been taking far too casually.

What Sleep Is Actually Doing

For most of human history we didn't really know why we slept. We knew we needed it, we knew the consequences of not getting it, but the mechanism was largely a mystery. In the last few decades that has changed significantly, and what researchers have found is remarkable.

Sleep is not downtime. Your brain is extraordinarily active while you sleep, doing work it simply cannot do while you're awake.

Two of the most important things happening are memory consolidation and waste clearance, and both of them should change how seriously you take your sleep.

Memory consolidation is the process by which your brain takes the experiences, information, and learning from your day and transfers them from short-term to long-term memory. This happens primarily during sleep. When you stay up late to cram before an exam, you are almost certainly undermining the very thing you're trying to do, because the consolidation process that would lock in what you studied gets cut short. Sleep isn't a reward after learning. It's a key part of learning itself.

The glymphatic system is the brain's waste clearance mechanism, and it's one of the more extraordinary things I've learned about human biology. Your brain is your most metabolically active organ, which means it produces a significant amount of cellular waste as a byproduct of all that activity. During waking hours, the channels that clear this waste are largely closed. During sleep, particularly deep sleep, they open wide and cerebrospinal fluid floods through, essentially washing the brain clean.

One of the waste products cleared by this process is amyloid beta, a protein that accumulates in the brain and is strongly associated with Alzheimer's disease. Chronic poor sleep doesn't just make you foggy the next day. Over years and decades, it may be contributing to the kind of buildup that underlies one of the most feared diseases of ageing. That connection is not yet fully proven but the evidence is substantial and growing.

Brain fog, by the way, is at least partly explained by this mechanism. When the glymphatic system hasn't had sufficient time to do its work, the residue of the previous day's thinking is still there. Your thoughts feel slow and sticky because, in a real sense, they are.

Beyond the brain, poor sleep is linked to increased cardiovascular risk, impaired immune function, disrupted blood sugar regulation, hormonal imbalance, weight gain, depression, and reduced life expectancy. It's not that bad sleep causes all of these things directly, but it creates the conditions in which they develop more easily and progress more quickly. The research in this area has grown dramatically in recent years and the picture it paints is not comfortable reading for those of us who have spent decades treating sleep as optional.

The Trap I Fell Into: More Is Not Always Better

When I started learning all of this I did what probably a lot of people do. I decided that if sleep was this important then I should be getting as much as possible. I started sleeping nine, ten, sometimes more hours a night.

It didn't help. In fact, some of my worst days were after my longest sleeps. Meanwhile some of my better days came after nights where I'd slept less than I intended.

It took me a while to understand what was happening, but it turns out that sleep has a sweet spot, and too much of it carries its own costs. Too much sleep is associated with many of the same health risks as too little, including cognitive impairment, cardiovascular issues, and increased mortality. The relationship between sleep and health is not a straight line where more is always better. It's a curve with an optimal range, and most adults sit somewhere between seven and nine hours, with around seven and a half being a commonly cited target.

These days I aim for seven and a half hours. I don't always hit it. Some mornings I need to wake early to take my wife to her shift, and those days I might get five hours. That disrupts things, and I feel it. But if I can catch up over the following day or two my body tends to stabilise. I've also found that listening to your body is more reliable than any fixed number. If I wake up feeling like I need more sleep, I take it when I can. Not everyone has that flexibility, and I recognise I'm fortunate in that regard.

Timing Matters as Much as Duration

This is the part that surprised me most, and the part most people overlook entirely.

It's not just how much you sleep. It's when you sleep, and how consistent that timing is from one night to the next.

The research has made it clear that going to sleep and waking up within the same fifteen to thirty minute window every day produces significantly better sleep quality than the same total hours at irregular times. Your body runs on a circadian rhythm, an internal clock that regulates everything from core temperature to hormone release, and that clock works best when it knows what to expect. Disrupting it, even occasionally, has measurable effects on how restorative your sleep actually is.

The best illustration I've come across for this is jet lag. When you fly across time zones your body clock is suddenly out of sync with the world around you, and you feel awful for days. You're not sleeping less, you're just sleeping at the wrong time relative to your internal rhythms. Now consider what happens every time you have a late night on the weekend and sleep in the next morning. You've shifted your body clock by hours. You've given yourself a version of jet lag without going anywhere. Monday morning fatigue isn't laziness. It's a mild but real time zone shift you've imposed on yourself over the weekend.

I'm currently going to sleep around ten-thirty and waking between six and seven, adjusted for whatever catch-up I need. My wife's shift work makes perfect consistency difficult, and I won't pretend I always get this right. But the weeks where my timing is most consistent are noticeably better than the weeks where it isn't. The difference is real enough that I've stopped treating sleep timing as a nice-to-have.

The Evening Before

There's a concept from Jewish tradition that has stayed with me since I first heard it. The Jewish day doesn't begin at midnight or at sunrise. It begins at sundown the evening before. In this traditional view, you don't wake up into a new day. You sleep into it.

When I first encountered this it was just an interesting cultural fact. Something to mention in conversation. But the more I sat with it, and the more I learned about what sleep actually does, the more it began to feel like a profound piece of practical wisdom dressed up as calendar convention. Everything I do in the hours before I sleep is already shaping the day that follows. The food I eat, the light I expose myself to, the thoughts I sit with, the screens I stare into, all of it is either preparing my body for the restoration that sleep offers or undermining it before it begins.

This shift in perspective changed how I think about evenings. They stopped being the end of the day and started being the beginning of the next one.

Practically, what this means is stopping eating at least three hours before bed, giving your digestive system time to settle and your core temperature time to drop, which is one of the signals your body uses to initiate sleep. It means stepping away from screens one to two hours before you intend to sleep, because the blue light they emit suppresses melatonin production and keeps your brain in a state of alertness it needs to wind down from. It means keeping your bedroom dark and cool, conditions that support the deeper stages of sleep where the most restorative work happens.

None of this is complicated. But it requires treating the evening as preparation rather than as leftover time.

The Morning After

How you wake up and what you do in the first hour matters too, and it connects back to how well you'll sleep the following night. But that deserves its own post and I'll give it one. For now the important thing is simply this:

Sleep is not the passive absence of wakefulness. It is active, purposeful, and foundational to almost everything else you're trying to do for your health. You can eat well, exercise regularly, and take the best supplements in the world, and chronic poor sleep will undermine all of it. It's not one piece of the puzzle. It might be the piece the rest of the puzzle sits on.

I came to this understanding late, and I'm still working on getting it right. But understanding what is actually happening while you sleep makes it a lot easier to take it seriously. It's not rest. It's maintenance. And you wouldn't skip maintenance on the only body you're ever going to have.

The morning routine and how it connects to sleep quality is coming in the next post. If you don't want to miss it, subscribe below.