Sleep hygiene that actually works

Most "sleep hygiene" lists are 20 items long and about 4 of them matter. The rest are filler you can safely ignore while you fix the parts that move the needle. Here is the short version, ordered by how much it actually helps.

Fix your wake time first, not your bedtime

The single most useful lever is getting up at the same time every day — weekends included. Your body clock anchors to when light hits your eyes in the morning, not to when you decide to go to bed. A fixed wake time pulls your sleep onset earlier on its own, because you build up a steady sleep drive across the day.

Bedtime is the output, not the input. Chase a fixed wake time and let sleep onset settle where it wants to. If you are lying awake for 30 minutes or more, get up, sit somewhere dim and dull, and go back only when you feel sleepy. Training your brain that the bed means sleep — not scrolling, not worrying — is the core idea behind cognitive behavioural therapy for insomnia (CBT-I), which is the first-line treatment for chronic insomnia and consistently outperforms sleep hygiene used on its own.

Get bright light early, dim light late

Light is the strongest signal your circadian system reads. Ten to twenty minutes of bright light within an hour or so of waking — ideally outdoors, even on a cloudy day — tells your clock that the day has started and sets the timer for feeling sleepy that night.

The evening is the mirror image. Bright light late, especially overhead white light, can push your clock later and delay sleep onset. You do not need to sit in the dark. Dimming the main lights an hour before bed and keeping screens off your face is enough for most people. The screen's content — a tense work thread, an argument, doomscrolling — probably keeps you up more than its blue light does.

Give caffeine a cutoff

Caffeine has a half-life of roughly five hours, which is a rule of thumb rather than a personal guarantee — some people clear it much faster or slower. The practical takeaway: a mid-afternoon coffee can still have a meaningful dose in your system at bedtime.

If you sleep poorly, try a cutoff around eight hours before bed and see whether it helps. That usually lands early-to-mid afternoon. You do not have to quit; you just have to move it earlier. Alcohol is the sneakier one — it helps you fall asleep and then fragments the second half of the night, so it trades falling asleep faster for worse sleep overall.

The tips that matter less than you'd think

• Magnesium, herbal teas, and most supplements. The evidence is thin and the effect, if any, is small. Not harmful; just not the lever.
• A perfectly cold, dark, silent room. Helpful at the margins. Worth doing if it's easy, not worth obsessing over.
• Tracking every night with a wearable. Useful for spotting trends over weeks. Checking the score each morning can turn into anxiety about sleep, which is itself a cause of bad sleep. Watch the monthly trend, ignore the nightly number.

A one-week starting point

1. Pick a wake time you can hold seven days a week. Set an alarm. Get up.
2. Get outside for light within an hour of waking.
3. Move your last caffeine to early afternoon.
4. Dim the lights an hour before bed; keep the bed for sleep only.

Give it two weeks before judging it — circadian shifts are slow. If sleep is badly broken for a month or more, or you suspect apnoea (loud snoring, waking gasping, daytime exhaustion despite time in bed), that is a conversation with a doctor, not a habit to hack. This is general information, not medical advice.