“Sleep hygiene” is a set of behavioural habits intended to make good sleep more likely. It is not a treatment for a sleep disorder, and presenting it as one is where a lot of advice goes wrong. But for people sleeping badly without an underlying condition, several of its components have reasonable evidence behind them — and a few widely repeated ones do not.

Consistency does more than duration targets

The body runs on a circadian rhythm anchored largely by light exposure and by the regularity of your schedule. Waking at the same time every day, including weekends, is the single most reliable way to stabilise it.

That is a more useful target than chasing a fixed number of hours. Sleep need varies between individuals, and most adults fall in a range rather than on a figure. If you wake without an alarm at roughly the same time and feel alert through the day, your duration is probably adequate whatever the number says.

Catching up with long weekend lie-ins shifts the rhythm later, which makes Monday harder — the pattern sometimes called social jetlag. If you are short of sleep, a modest early night is better than a late morning.

Light in the morning, dark in the evening

Morning daylight is a strong signal to advance the clock and improves alertness during the day. Getting outside within an hour or so of waking, even briefly and even under cloud, delivers far more light intensity than indoor lighting does.

In the evening the goal is the reverse: dim the environment for the last hour or two. The screens question is more nuanced than headlines suggest — the light itself matters less than what you are doing with the device. Content that keeps you alert and engaged delays sleep more than the wavelength of the display does.

Caffeine, alcohol and timing

Caffeine has a half-life of roughly five to six hours in most adults, meaning a mid-afternoon coffee still has meaningful levels in your system at bedtime. Individual metabolism varies widely; if you sleep badly, moving your cut-off earlier is a cheap experiment.

Alcohol is the more misunderstood one. It shortens the time to fall asleep and then degrades the second half of the night, suppressing REM sleep and increasing awakenings. It is a sedative, not a sleep aid.

Large meals close to bedtime disrupt sleep for some people, particularly with reflux. Going to bed hungry is not better. A light snack is fine.

The bedroom itself

  • Cool. Core body temperature falls as you fall asleep, and a cool room supports that. Most guidance lands somewhere around 16–19°C.
  • Dark. Blackout curtains or a mask, and remove standby lights.
  • Quiet, or consistently noisy. Steady background sound is less disruptive than intermittent noise; a fan or white noise can help in a loud environment.
  • Reserved for sleep. Working in bed weakens the association between the bed and sleeping, which is the mechanism behind several effective insomnia treatments.

What to do when you cannot sleep

Lying awake trying harder is counterproductive; it reinforces the association between bed and frustration. The standard behavioural advice is to get up after around twenty minutes, go to another room, do something quiet and dull in low light, and return when you feel sleepy.

Clock-watching makes this worse. Turn the display away.

Exercise, naps and the things people worry about

Regular physical activity improves sleep quality for most people. Evening exercise is not automatically disruptive — the evidence for a blanket ban is weak — though vigorous training in the last hour before bed does delay sleep onset for some.

Short naps of around twenty minutes early in the afternoon improve alertness without much effect on the following night. Long or late naps reduce the sleep pressure you need at bedtime.

When this is not the answer

Sleep hygiene is a reasonable first step for mild, situational poor sleep. It is not sufficient for a diagnosed disorder, and persistent problems deserve proper assessment rather than another round of habit changes.

Speak to a doctor if you have difficulty sleeping most nights for more than a month, loud snoring with pauses in breathing or gasping, significant daytime sleepiness that affects driving or work, or an irresistible urge to move your legs at night. For chronic insomnia, cognitive behavioural therapy for insomnia (CBT-I) is the recommended first-line treatment in major clinical guidelines — ahead of medication.

This article is general information and does not replace individual medical advice.