Sleep hygiene is the collection of behavioural and environmental practices intended to support healthy, consistent sleep. The term does not mean physical cleanliness; "hygiene" is used in the broader sense of practices that promote health. Sleep hygiene commonly includes maintaining a regular sleep schedule, obtaining daylight and physical activity during the day, limiting stimulants such as caffeine late in the day, avoiding heavy alcohol use as a sleep aid, reducing excessive evening stimulation and keeping the bedroom suitable for sleep. It is best understood as a set of supportive habits rather than a treatment that can cure every sleep disorder.
A central component of sleep hygiene is consistent timing. Going to bed and waking at broadly similar times each day helps reinforce the circadian system, although exact rigidity is unnecessary for most people. The wake time is particularly useful as an anchor because morning activity and light exposure provide strong signals to the biological clock. Sleeping substantially later on days off can feel restorative after insufficient weekday sleep, but large changes can also make it harder to fall asleep at the desired time afterward. A consistent schedule should nevertheless allow enough total sleep rather than being used to justify chronically restricting sleep.
Sleep hygiene also concerns the relationship between the bedroom and sleep. Ideally, the bed is primarily associated with sleeping and, where relevant, sexual activity rather than prolonged work, gaming, worrying or watching stimulating entertainment. This principle is particularly important in behavioural treatment for insomnia because repeated wakefulness in bed can strengthen an association between the bed and alertness. Keeping the room dark, quiet and comfortable can reduce environmental disruption. If noise or light cannot be eliminated, practical measures such as earplugs, an eye mask or blackout curtains can sometimes help.
Stimulants and substances are another major part of sleep hygiene. Caffeine blocks adenosine receptors and can reduce perceived sleepiness, with effects lasting well beyond the period in which a person feels the initial stimulation. Individual sensitivity varies, so some people need to stop caffeine in the early afternoon while others can tolerate later consumption. Nicotine is also stimulating. Alcohol can initially increase sleepiness but often produces more fragmented sleep as its effects wear off. Neither alcohol nor sedating recreational substances should be treated as dependable methods of improving restorative sleep.
Evening routines are included within sleep hygiene because the transition from active daytime behaviour to sleep can influence arousal. A period of quiet activity, dimmer lighting and predictable preparation for bed can help establish a behavioural cue for sleep. Reading a non-stimulating book, taking a warm bath or shower, gentle stretching and relaxation exercises are examples that may help. The specific activity is less important than whether it reduces mental and physiological activation. A routine that involves stressful work, intense gaming, emotionally charged discussions or repeated checking of messages may make the transition to sleep more difficult for some people.
Daytime behaviour is as important as what happens immediately before bed. Regular exercise, sufficient exposure to outdoor light and avoiding excessive daytime sleep can strengthen sleep drive and circadian alignment. Long or late naps can reduce the homeostatic pressure that would otherwise build before bedtime. Conversely, someone who is dangerously sleepy may need a nap for immediate safety, and people with certain schedules or health conditions may deliberately use naps. Sleep hygiene therefore involves balancing daytime sleep with the individual's total sleep requirement and schedule rather than imposing a universal ban on napping.
Sleep hygiene has limitations. Someone with obstructive sleep apnoea cannot reliably resolve the underlying airway obstruction simply by making the bedroom darker, and someone with chronic insomnia may need structured CBT-I rather than generic advice to "sleep better". Likewise, restless legs syndrome, circadian rhythm disorders, chronic pain, depression, medication effects and other conditions can persist despite excellent sleep habits. Sleep hygiene is consequently best regarded as foundational support. It can remove avoidable barriers to sleep but does not replace diagnosis and treatment when a disorder is present.
The concept has become widespread because it translates sleep science into practical behaviour, but individual recommendations should not become unnecessarily rigid. For example, insisting that a person must never use a screen in the evening is stronger than the evidence supports for every individual. Similarly, waking at exactly the same minute every day is unnecessary if the overall schedule is stable. Good sleep hygiene means creating conditions that favour adequate, regular and restorative sleep while recognising individual variation. The most important principles are sufficient sleep opportunity, stable circadian timing, an appropriate environment and avoidance of behaviours or substances that predictably interfere with sleep.
