What I Wish I'd Known About Sleep at Eighteen

I watched a long conversation with the sleep scientist Matthew Walker last week, at the age of 49, and I’ve been thinking about it a lot since.

Walker has spent decades researching sleep, and the conversation moves through most of what he has learned. What struck me was not any single fact but the cumulative impact of sleep on the body and mind. Sleep is not one input among many that support a functioning life. It sits underneath almost everything else. Mental health, physical health, immune function, memory, longevity, mood, decision-making.

Take sleep away for a few nights running, and all of it starts to fail at once, in a way that no amount of willpower or coffee fixes.‍ ‍

I have known, in a loose sense, that sleep matters for most of my adult life. What I had not properly understood was how central it actually is. Listening to Walker lay it out properly, methodically, with the evidence behind each claim, was different from having half absorbed the idea from headlines over the years.‍ ‍

I have had chronic insomnia for most of my life. Decades of broken nights, stretched further by the kind of work life that treats sleep as the thing you sacrifice first when there is too much to do. I built companies. I raised children. I told myself, the way I suspect a lot of people tell themselves, that I was managing. That I was one of the people who could get by on less.‍ ‍

Watching that conversation, I found myself doing the maths on what that might actually have cost. Not in a dramatic way. Just quietly, adding it up. Years of poor sleep, layered underneath everything else I was doing, almost certainly shaping my mood, my patience, my health, my capacity to think clearly, in ways I never properly connected to the cause.‍ ‍

Nobody taught me this at eighteen. Nobody sat me down and explained, with any seriousness, that sleep was not a lifestyle preference but closer to a biological requirement with consequences attached to ignoring it. I picked up scraps of it over the years, the way most people do, mixed in with a lot of bad advice and folk wisdom that did not hold up.‍ ‍

That is the question this has left me with.

Should schools be teaching this properly?

Not as a passing mention in a wellbeing lesson, but as something closer to a serious subject, given how much rests on it.‍ ‍

There is already a research thread on this, and it is more mixed than I expected. A 2026 study in Nova Scotia found teachers wanted better sleep resources for their classrooms and felt they did not have them. Earlier trials, including a 2023 cluster randomised study and a 2022 pilot programme, found that sleep education in schools reliably improves what children know about sleep, and improves some habits, but does not move the actual number of hours slept nearly as much. The CDC points to school start times as a separate lever entirely, one that may matter as much as anything taught in a classroom.‍ ‍

That gap, between knowing and doing, is one I recognise personally. Knowing that sleep matters has never been enough to fix mine. Insomnia does not respond to good intentions. But I keep coming back to a different question. Even if better knowledge would not have solved my sleep, would it have changed how I organised the rest of my life around it? Would I have protected the time I did have differently, treated the warning signs with more seriousness, built habits earlier that made the difference at the margins?‍ ‍

I do not know the answer. But I wish I had been given the chance to find out at eighteen rather than forty-nine.‍ ‍I almost feel silly for not having spotted it. It now seems so obvious.

There is a particular irony in all of this that has not escaped me. I have spent years telling my own children how important sleep is, chasing bedtimes, trying to build some sort of regularity into their nights, the way any parent does. Meanwhile, I have been running on broken sleep myself the entire time, quietly demonstrating the opposite of what I was preaching. Children notice that gap eventually, even when they are too young to say so. I am not sure which of us that particular lesson was actually for.

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