Sleep hygiene

Sleep hygiene is the list. Dark room, cool room, no caffeine after lunch, no screens before bed, no alcohol, regular hours, bed is for sleeping, get up if you cannot sleep. You have read it. If you are reading this page, you have probably also done it, and are wondering why it did not work.

Here is the thing the list is rarely sold with. Sleep hygiene was never designed as a treatment. Peter Hauri assembled it in 1977 as a set of general habits for the public, and it has since become the default answer a tired person gets from a search engine, a GP appointment and a well-meaning friend. The evidence for it as advice to a population is decent. The evidence for it as treatment for a person with insomnia is poor enough that the profession now recommends against it.

This is not a debunking. Irish and colleagues' 2015 review went through the individual components and found real support for most of them as influences on sleep in the general population: caffeine and alcohol measurably degrade sleep, irregular timing measurably degrades it, and daytime exercise measurably helps.

So if you sleep reasonably well and want to sleep better, the list is a fine place to start, and the items at the top of it — consistent wake time above all — are the ones with the most behind them.

The list also does something useful for a person with no framework: it names the variables. Someone who has never considered that the 4pm coffee might be in their midnight is better off having considered it.

Stepanski and Wyatt made the argument in 2003 and two decades of evidence have gone their way: sleep hygiene addresses the things that cause poor sleep in someone who sleeps normally, and chronic insomnia is not maintained by those things. It is maintained by arousal and by the behaviours that build up around the bed — the extra hour lying there, the clock-watching, the afternoon nap, the effort.

The meta-analytic picture is consistent. Chung and colleagues' 2018 review in Family Practice pooled the trials and concluded that sleep hygiene education is clearly less effective than cognitive behavioural therapy for insomnia, with the reviewers unable to establish that it has a useful role even as a first step.

Then the guidelines followed. The American College of Physicians in 2016 made CBT-I the first-line treatment for chronic insomnia in adults. The American Academy of Sleep Medicine's 2021 guideline went further and issued a conditional recommendation against sleep hygiene as a single-component therapy — one of very few things in that document with a recommendation against it at all.

There is a specific harm in this, beyond the wasted months. A person who follows the list carefully and still lies awake concludes something about themselves rather than about the list. That conclusion — I have tried everything, so it must be me — is itself arousal, and arousal is the mechanism. The advice ends up feeding what it was meant to fix.

CBT-I, cognitive behavioural therapy for insomnia. It is not the list with a therapist attached. Its two most active parts are the ones the list never mentions, and both feel counterintuitive:

• Stimulus control. The bed is reserved for sleep. If you are awake and frustrated, you get up and leave, and you come back when sleepy. The point is to stop the bed from being the place where you lie awake, because a bed that reliably predicts wakefulness produces wakefulness.
• Sleep restriction. You spend less time in bed, not more — matched at first to how much you are actually sleeping — so that the time in bed becomes dense with sleep, and then it is extended back out week by week. Almost nobody arrives at this on their own, because every instinct says the opposite.

Around those sit the cognitive work on the 3am arithmetic and the catastrophising about tomorrow, which the entry on tired but wired describes in more detail, and a regular wake time, which is the one item the hygiene list and CBT-I agree on completely.

CBT-I is delivered by clinicians and by well-validated digital programmes, and it outperforms sleeping medication over the long run. This page is not that, and cannot be. If you have had three or more bad nights a week for three months or more, that is the threshold where chronic insomnia is the working word and a doctor is the next step — and it is worth saying to them that you have already done the hygiene list, because it shortens the conversation.

Keep the wake time. It anchors everything downstream and it is the one habit that survives every version of the evidence.

Keep caffeine timing, for the reason set out in the entry on caffeine — the half-life is longer than people assume, and this one is about chemistry rather than discipline.

Keep the evening light discipline, but for the right reason: brightness and timing, not the wavelength, as screens and sleep sets out.

And stop treating the remaining items as a moral scorecard. The person who has blackout blinds, a cold room, a charging station in the hallway and a paper book, and who is still awake at two, does not have a hygiene problem. They have something the list was never built to treat, and the useful next move is not a stricter list. It is a different one — and, if the shortfall is opportunity rather than ability, the entry on sleep debt is the other half of the question.