Most people blame stress for poor sleep. In practice, three adjustable variables do most of the work: when your eyes see bright light, when your core temperature drops, and how much caffeine is still circulating at bedtime. Fix them in this order and give it two weeks.

1. Anchor your wake time, not your bedtime

Your body clock calibrates itself from the first bright light you see in the morning, not from the hour you climb into bed. Hold your wake time within a 30-minute window every day and your natural sleep onset usually moves earlier within a week. Sleeping in until noon on Sunday is effectively giving yourself a six-hour jet lag every seven days.

2. Do the caffeine half-life maths

Caffeine has a half-life of roughly five to six hours. A 3pm americano still leaves about a quarter of its dose active at 11pm — not always enough to keep you awake, but often enough to shave the deep-sleep portion of your night. Move your last caffeinated drink to before 2pm and see what changes.

3. Build a 60-minute cool-down sequence

Falling asleep requires your core temperature to fall by roughly half a degree. A repeated sequence teaches your body to do it on cue:

  • Dim the main lights 60 minutes before bed and switch to warm, local lighting
  • Take a 10-minute bath or shower at about 38-40°C; the rebound afterwards is what makes you drowsy
  • Put the phone on night mode and out of arm's reach
  • Write down tomorrow's three most important tasks so your brain stops rehearsing them

4. If you wake at night, do not check the clock

Brief night wakings are normal. Checking the time starts a countdown in your head and switches on the alerting side of your nervous system. If you are still awake after 20 minutes, get up, do something dull in dim light, and return when you feel sleepy.

Frequently asked questions

Do I need a full eight hours?

No. Most adults land between 7 and 8.5 hours, and the spread between individuals can exceed an hour. The useful test is whether you stay alert through the day, not the number on the clock.

Does catching up at the weekend work?

It repays short-term sleep debt but does not repair your rhythm. Keep the lie-in to about an hour past your usual wake time.