The day decides the night

You do not fix sleep at bedtime.

Nobody fixes sleep at eleven o'clock

The standard approach to sleeping badly is to intervene at bedtime: an earlier alarm for going to bed, a darker room, no screens for an hour, a supplement. Some of that helps a little. None of it addresses the thing that decided the night, which had mostly finished deciding by about four in the afternoon.

Sleep is a consequence. By the time you are lying there, the inputs are in: when you woke, whether you saw daylight, when and what you ate, whether you moved, how much caffeine and when, and what you did with the last two hours. The eleven o'clock decision is the smallest lever in the day and it is the only one most people pull.

What the sixteen hours before are doing

Four things, each of which is settled enough to act on.

• Morning light. Daylight within an hour of waking is the strongest signal the body clock receives, and it sets the timing of the evening's sleepiness roughly sixteen hours later. Indoor lighting is not a substitute; the difference between a bright room and outdoors on a dull day is larger than it looks.
• Caffeine, and its half-life. Caffeine takes about five to six hours to halve in most adults. A coffee at four in the afternoon leaves a meaningful fraction circulating at midnight, and it does not necessarily stop you falling asleep. It reduces the deep portion, which is why a night can be eight hours long and not restorative.
• The time of the last meal. Digestion and sleep onset compete. Eating close to bed reliably produces lighter sleep in the first part of the night, which is the part that matters most.
• Movement, somewhere in the day. The effect is large and it is not fussy about which exercise. Timing matters only at the edges: very hard effort in the last hour or two is counterproductive for some people.

What Ayurveda noticed, and what holds up

Ayurveda organises the day into periods and attaches qualities to them, and one of its claims is specific enough to be interesting: the hours before about ten in the evening are described as heavy and settling, and the hours after as light and activating, with the consequence that somebody still awake at half past ten will often find a second wind and stay up another two hours.

Most people recognise that pattern from experience. The traditional framing and the modern one agree on the observation and explain it differently: the modern account is the circadian rise in alertness that occurs before the drop into sleep, and missing the window means waiting for the next one.

It is worth being clear about what that does and does not license. The timing observation is useful and testable on yourself in a week. The wider system of constitutional types and the prescriptions that follow from them is a different kind of claim with a different evidence base, and this guide is not making it.

The order to try things in

Cheapest and most effective first, which is the reverse of how people usually proceed.

One: daylight within an hour of waking, ten minutes, outdoors. Two: a fixed wake time, including at weekends, which does more for sleep than a fixed bedtime because the wake time is the anchor the clock actually uses. Three: move the last coffee earlier, by hours rather than minutes. Four: finish eating two to three hours before bed. Five, and only then, the bedroom: dark, cool, and the phone somewhere else.

Supplements come sixth at best, and the common ones are mild. They are not a substitute for any of the five above, and a great deal of money is spent on them by people who have not tried the first one.

When this is not the answer

Some sleep problems are not behavioural. Loud snoring with pauses, waking unrefreshed after genuinely sufficient hours, persistent early waking alongside low mood, or sleepiness that interferes with driving are all reasons to see a doctor rather than to adjust a routine. Sleep apnoea in particular is common, frequently undiagnosed, and not improved by going to bed earlier.

Nothing above is a treatment for anything, and if a clinician has given you a plan, theirs supersedes this.