Sleep hygiene: what actually works
Last reviewed: 14 September 2026
Every sleep hygiene list presents a dozen habits as equally important. They are not — two of them do most of the work, and the one usually placed first belongs near the bottom.
Useful, but oversold
Sleep hygiene is the set of daily habits that make good sleep more likely — consistent timing, light exposure, a cool dark room, and what you consume in the evening.
It is genuinely worth getting right, and it is not a treatment for insomnia on its own. For persistent insomnia the NHS recommends cognitive behavioural therapy, and sleep hygiene advice alone is one of the weaker interventions when tested in isolation. It is the foundation, not the cure.
The advice, ranked by how much it actually matters
Most sleep hygiene lists present a dozen items as equally weighted. They are not. Here they are in rough order of effect.
1. A consistent wake-up time
The strongest single habit, and the most commonly skipped. Getting up at the same time seven days a week — within about an hour — anchors your body clock, which sets when you will get sleepy that evening. Everything else is easier once this is stable. The NHS puts "going to bed and getting up at similar times each day" at the top of its list too.
2. Morning daylight
Light is the main input your body clock takes its cue from, and outdoor light is many times brighter than indoor lighting even on an overcast day. Fifteen minutes outside within an hour of waking pulls your clock earlier. This is the single most effective thing available for anyone whose bedtime has drifted late.
3. Caffeine timing
Caffeine has a half-life of roughly five to six hours, so half of a 3:00 PM coffee is still circulating at 9:00 PM. The NHS advises avoiding caffeine for at least six hours before bed. This matters more for some people than others — sensitivity varies considerably — but if you sleep badly and drink coffee after lunch, it is the cheapest experiment available.
4. Alcohol
Worth separating from caffeine because it works differently and is more commonly misunderstood. Alcohol is a sedative: it shortens the time to fall asleep, which is why it feels helpful. It then suppresses REM sleep and fragments the second half of the night, and produces the characteristic 3:00 AM waking as it clears. A nightcap reliably trades sleep quality for sleep onset.
5. A cool, dark, quiet bedroom
Core body temperature has to fall for sleep to consolidate, and an over-warm room fragments deep sleep more reliably than most other environmental factors. Dark and quiet matter too, and earplugs, an eye mask and blackout curtains are all reasonable fixes.
6. Not using bed for being awake
Keep the bed for sleep. Working, scrolling and lying awake in it all weaken the association you want. If you are awake for about 20 minutes, get up.
7. Screens before bed
Last on the list deliberately, because it is usually placed first and the effect is smaller than assumed. Blue light at typical screen brightness does suppress melatonin somewhat, but the larger problem is plainer: content designed to be hard to stop is hard to stop, and time on a device is time not asleep. The NHS advises avoiding screens for an hour before bed; the reason that works is mostly displacement.
What the NHS actually recommends
Condensed from NHS guidance on insomnia and sleep:
| Do | Don't |
|---|---|
| Go to bed and get up at similar times each day | Smoke, or drink alcohol, tea or coffee within 6 hours of bed |
| Relax for at least an hour before bed | Use screens right before bed |
| Keep the bedroom dark, quiet and cool | Eat a big meal late |
| Exercise regularly during the day | Nap during the day if it stops you sleeping at night |
| Write down worries before bed | Force it — get up after about 20 minutes |
Where sleep hygiene stops being the answer
If you have been doing all of this for a month and still sleeping badly, more sleep hygiene is not the next step. Insomnia that has become self-sustaining responds to cognitive behavioural therapy for insomnia (CBT-I), which targets the thoughts and behaviours keeping it going rather than the daily habits around it. The NHS offers CBT for insomnia face to face and through online programmes, and it is what a GP is likely to suggest.
And some sleep problems are not behavioural at all. Sleep apnoea, restless legs, thyroid problems, anaemia and depression all cause poor or unrefreshing sleep, and no bedtime routine resolves any of them.
The NHS advises seeing a GP or doctor if changing your sleep habits has not helped, if you have had trouble sleeping for months, or if it is affecting your daily life. Also see a GP or doctor if anyone has noticed you gasping, snorting or choking in your sleep — that points at sleep apnoea, which no amount of sleep hygiene will fix.
Sources. Self-help advice follows NHS guidance on insomnia, sleep and tiredness, alongside the American Academy of Sleep Medicine's recommendations. Cognitive behavioural therapy for insomnia (CBT-I) is the treatment the NHS recommends for persistent insomnia. This page is general wellbeing information, not medical advice — see a GP or doctor if sleep problems have lasted months or are affecting your daily life.
Common questions
What is sleep hygiene?
The set of daily habits and environmental conditions that make good sleep more likely: consistent sleep and wake times, morning daylight, caffeine and alcohol timing, and a cool, dark, quiet bedroom.
What does the NHS say about sleep hygiene?
The NHS advises going to bed and getting up at similar times each day, relaxing for at least an hour before bed, keeping the bedroom dark and quiet, and exercising regularly. It advises against alcohol, tea, coffee or smoking within six hours of bed, and against screens immediately before bed.
What is the most important part of sleep hygiene?
A consistent wake-up time, seven days a week. It anchors your body clock, which determines when you get sleepy that evening. Morning daylight is a close second.
Does sleep hygiene cure insomnia?
Not on its own. Sleep hygiene advice tested in isolation is one of the weaker interventions for insomnia. For persistent insomnia the NHS recommends cognitive behavioural therapy for insomnia, which targets the thoughts and behaviours sustaining it.
How long before bed should I stop drinking coffee?
The NHS advises at least six hours. Caffeine's half-life is roughly five to six hours, so half of a mid-afternoon coffee is still circulating at bedtime. Sensitivity varies a lot between people.
Do screens before bed really affect sleep?
Somewhat, but less than usually claimed. Blue light suppresses melatonin to a degree, though the bigger effect is displacement — engaging content is hard to stop, and time on a device is time not asleep.