Sleep hygiene: what the rules are worth

What is sleep hygiene?

A set of everyday habits and bedroom conditions meant to protect sleep, first put together for people with mild to moderate insomnia (Irish and colleagues, 2015). Definitions differ from one study to the next, and so do the rules, but most lists include some of these:

• Keep regular times for going to bed and getting up.
• Avoid caffeine, nicotine and alcohol close to bedtime.
• Exercise regularly — traditionally, not too close to bed.
• Wind down, and deal with worries before bed.
• Keep the bedroom quiet, dark and comfortable.
• Avoid long daytime naps.

Newer lists often add no screens in bed, no clock-watching, and the bed for sleep only. That last one is really stimulus control, a technique of its own with a guideline recommendation behind it (Edinger and colleagues, 2021) — the bed is a cue explains it.

Where does the term sleep hygiene come from?

The list as clinicians know it is usually traced to Peter Hauri, who set out sleep hygiene recommendations in 1977 in The Sleep Disorders, a booklet published by the pharmaceutical company Upjohn (Hauri, 1977). It was written for people with mild to moderate insomnia, and it was meant to be tailored: Hauri’s idea was to fit the recommendations to the person, and he later tried single consultations that gave each patient two to four rules chosen for them (as Irish and colleagues, 2015, describe it).

The public-health version went the other way, handing everyone the same complete list. The idea itself is older than either. Hygiene, in its older and broader sense, meant the habits that keep you well, and the word was being applied to sleep long before 1977: the Texas Medical Journal ran a page titled “The Hygiene of Sleep” in 1900.

Does sleep hygiene work?

As a treatment for insomnia, not well. A 2018 review of 15 studies found that people given sleep hygiene education did improve, by a small to medium amount, but significantly less than people given cognitive behavioural therapy for insomnia (CBT-I). The gains showed up only in what people reported, not in objective measures, and none of the studies compared it with no treatment at all (Chung and colleagues, 2018). The American Academy of Sleep Medicine’s 2021 guideline suggests that clinicians not use sleep hygiene as the only treatment for chronic insomnia (Edinger and colleagues, 2021).

As advice for everyone else, the honest answer is that it has rarely been tested. A 2015 review went through the evidence rule by rule and found that most of the individual habits are linked with how people sleep — but that the effect of actually following them, in ordinary people, is “largely untested” (Irish and colleagues, 2015).

The authors’ own question is the useful one: if each rule is related to sleep, why does handing someone the whole list do so little? Part of their answer is that much of the evidence comes from extreme laboratory conditions — large doses of caffeine at bedtime, say — that tell you little about a cup at four in the afternoon. Another part is that the rules are vague, and a list built for everyone fits no one exactly.

Which sleep hygiene rules have the most evidence?

Going rule by rule through the same review, the strength of the case varies a great deal.

Two popular rules are not in that review and have pages of their own here: screens before bed, where the evidence is weaker than the warnings, and a cool bedroom, which you have to cool down first explains.

What the table suggests is a short list worth keeping — caffeine early, no nightcap, a quiet room, regular exercise, a steady wake time — and a longer list worth holding lightly.

Why can following sleep hygiene rules make sleep worse?

Because a list of rules about sleep is a list of reasons to think about sleep. The clinical account of how poor sleep takes hold runs from attention to intention to effort — noticing sleep, meaning to sleep, trying to sleep — and sleep, being largely automatic, is inhibited by focused attention and by direct attempts to control it (Espie and colleagues, 2006). Ten rules checked at bedtime are ten small acts of attention, and a broken rule becomes an explanation, in advance, for a bad night. Why trying to sleep keeps you awake goes further into it.

The rules can also pull against each other. The 2015 review points out that changing one habit can shift another — give up naps and you may drink more coffee to get through the afternoon — and that some poor habits are a response to poor sleep rather than its cause: the nightcap taken to get to sleep, the extra coffee after a bad night. Taking away the habit does not take away what it was answering (Irish and colleagues, 2015).

So the version worth keeping is closer to Hauri’s than to the poster’s: two or three rules that fit your life, followed without auditing them.

What should you do instead of a list of rules?

For an ordinary evening, use the handful of rules with evidence as the frame of a routine rather than a test. A bedtime routine for adults goes through each part and gives an example evening, and how to fall asleep covers what to do once you are in bed.

For insomnia — trouble sleeping on most nights, for months, that is affecting your days — the recommended first treatment is CBT-I, by the American College of Physicians (Qaseem and colleagues, 2016) and the American Academy of Sleep Medicine (Edinger and colleagues, 2021). It usually includes sleep hygiene, but as one part of a package that commonly also holds stimulus control (keeping the bed for sleep), sleep restriction (matching the time spent in bed to the sleep you actually get), relaxation, and cognitive therapy for the worry about sleep itself, traditionally over four to eight weekly sessions (Dautovich and colleagues, 2010). The 2021 guideline rates several of those parts, even on their own, above sleep hygiene on its own.