What this page is
This is background reading. It exists so that if you eventually sit down with a doctor about your sleep, you arrive with useful vocabulary and a description of what is actually happening rather than the word tired. It does not diagnose anything, it does not tell you what a symptom means, and it does not recommend any medication or supplement. Those are decisions made about one person by a clinician who has spoken to that person.
How much sleep, and why the number is a range
Published guidance gives ranges by age rather than a single figure, because the requirement genuinely varies between people and the evidence supports a band, not a target.
| Age group | Commonly cited range | What tends to complicate it |
|---|---|---|
| Adults 18-64 | 7-9 hours | Chronically running well under this is associated with metabolic and cardiovascular risk in population data |
| Adults 65+ | 7-8 hours | Lighter sleep and an earlier wake time are ordinary age changes, not necessarily a disorder |
| Teenagers 14-17 | 8-10 hours | Biological timing shifts later while school start times do not, which produces chronic shortfall |
| Children 6-13 | 9-11 hours | Evening screen use and activity schedules push bedtime past the window |
A practical read on your own number: if you are not fighting sleepiness during ordinary daytime tasks, and you do not need to add two or more hours at the weekend to function, you are probably getting close to enough. If you do need that weekend catch-up, the weekday total is the thing to look at. The sleep cycle calculator works backwards from a wake time to sensible bedtimes, and the sleep debt calculator puts a number on the weekday shortfall you are trying to repay on Saturday.
The habits, in order of how much they matter
The list below is conventional and boring, and the order is the useful part. People usually start at the bottom of it, buying a pillow or an app, and never do the top item.
| Habit | What it does |
|---|---|
| Fixed wake time | The single highest-leverage change. Your body clock anchors to when light and activity begin, not to when you get into bed. Holding the wake time steady, weekends included, is what eventually pulls the sleep onset into place |
| Bed is for sleep | Working, scrolling and watching in bed teaches the brain that the bed is a place where you are awake. Reversing that association is one of the mechanical parts of insomnia treatment |
| Caffeine timing | Caffeine has a half-life of roughly five to six hours, so a mid-afternoon dose still has meaningful blood levels at bedtime. Sensitivity varies widely and some people clear it far more slowly |
| Naps kept short and early | A long or late nap spends the sleep pressure that would otherwise carry you into the night |
| Daytime light and movement | Morning light exposure and regular exercise both support the timing signal. Vigorous exercise immediately before bed suits some people and not others |
| Bedroom conditions | Dark, quiet, and on the cool side. These matter, but they are the last few percent, not the fix |
| Late meals | Finishing eating a couple of hours before bed avoids reflux and discomfort. Being genuinely hungry is also disruptive, so this is not a rule about fasting |
Alcohol, screens, and two claims worth separating
Alcohol is the most commonly used sleep aid and one of the worst. It reliably shortens the time it takes to fall asleep, which is why the belief persists, and then fragments the second half of the night as it is metabolised. People who use it to get to sleep often describe waking at three or four in the morning and not understanding why.
Screens are more nuanced than the popular version. The blue-light story is the part that gets repeated, and the evidence that screen colour temperature meaningfully changes sleep in ordinary use is weaker than the number of night-mode settings would suggest. The better-supported problem is behavioural: the content is engaging, engagement is arousing, and the device makes it very easy for bedtime to slide by an hour without a decision being made. Putting the phone down thirty to sixty minutes beforehand addresses the mechanism that is actually doing the damage.
When sleep will not come, and what the evidence supports
Lying awake trying harder is counterproductive, because the effort itself is arousing. The standard advice is to get up after roughly twenty minutes, go somewhere dim, do something dull, and return when sleepy. It feels like giving up and it is the opposite.
For insomnia that has become chronic, the first-line treatment in current clinical guidance is not a drug. It is cognitive behavioural therapy for insomnia, a structured short course that includes the bed-association work and a scheduling component, and it outperforms medication over the long run. Prescription sleep medication has a role, and that role is defined by a prescriber, usually short-term and alongside the behavioural work rather than instead of it.
On the shelf products: the evidence base for most over-the-counter sleep supplements is thin, inconsistent, or specific to circumstances such as jet lag rather than to ordinary insomnia, and the supplement category is not regulated for content and dose the way medicines are. This page does not tell you to take any of them or not to. It tells you that the marketing is well ahead of the evidence, and that anything you take nightly for months is something to raise with a doctor or pharmacist rather than decide alone.
The point where this stops being a habits problem
Some sleep complaints are not about hygiene at all, and no amount of routine adjustment will touch them. Bring these to a clinician rather than working on them yourself.
| What you notice | Why it is a clinical question |
|---|---|
| Difficulty falling or staying asleep three or more nights a week, persisting past about a month | This is the threshold at which insomnia is generally assessed rather than waited out, and the effective treatment is a structured course you cannot self-administer from a list |
| Loud snoring with witnessed pauses in breathing, gasping or choking | Sleep-disordered breathing is evaluated with a sleep study; it is not a habit and it carries cardiovascular consequences |
| Severe daytime sleepiness despite adequate time in bed | Adequate quantity with inadequate restoration points somewhere other than scheduling |
| An urge to move the legs at rest that is relieved by moving them | A recognised pattern with its own assessment path; a clinician distinguishes it from ordinary restlessness |
| Falling asleep involuntarily during the day, or while driving | An immediate safety matter as well as a medical one |
If you take one thing to that appointment, make it a record rather than a recollection. Two weeks of bedtime, wake time, night wakings, caffeine and alcohol, and a one-line note on the day is more informative than any description you will produce from memory, and it is what a clinician will ask for anyway. The mood and sleep log is set up for exactly that, and the point of keeping it is not to grade yourself — it is to hand someone else a pattern you cannot see from inside it.
Questions people ask
Is seven hours enough, or do I need eight?
Both sit inside the range that adult guidance gives, which is roughly seven to nine hours, and the requirement genuinely differs between people. The practical test is not the number on the clock but whether you are fighting sleepiness during ordinary daytime tasks and whether you need to add hours at the weekend to keep functioning. If you do, the weekday total is where to look.
How late can I drink coffee?
Caffeine has a half-life of roughly five to six hours, which means a substantial fraction of an afternoon dose is still circulating at bedtime. Sensitivity varies a great deal and some people clear it much more slowly than others, so the useful approach is to move your last dose progressively earlier for a couple of weeks and see whether anything changes, rather than adopting a fixed cut-off time from a page.
Should I lie there and wait for sleep to come?
The conventional advice is the opposite. After about twenty minutes of lying awake, get up, go somewhere dim and do something undemanding, and return to bed when you feel sleepy. Long stretches of frustrated wakefulness in bed strengthen the association between the bed and being awake, which is one of the things that keeps insomnia going.
Are over-the-counter sleep supplements worth trying?
This page does not recommend any product, and there is a real gap between how confidently these are marketed and what the evidence supports. Results are inconsistent, much of the research addresses specific situations such as jet lag rather than ordinary insomnia, and supplements are not regulated for content and dose the way medicines are. Anything you are considering taking nightly for months is a conversation to have with a doctor or pharmacist.
At what point should I actually see someone?
Common thresholds are trouble falling or staying asleep three or more nights a week for around a month, loud snoring with witnessed pauses in breathing, heavy daytime sleepiness despite enough time in bed, or falling asleep involuntarily during the day. The first of these is treated most effectively with a structured behavioural course rather than medication, so seeing someone early is not an escalation.