Sleep tools

Start with the two things that move the needle

Almost everything written about sleep hygiene is a variation on two levers. The first is a consistent rise time, because the body clock takes its cue from when light hits your eyes rather than from when you decide to go to bed. The second is enough time in bed, which sounds too obvious to state until you count the hours you actually leave for it on a weeknight.

The rest — room temperature, screens, caffeine timing, what you eat late — matters mainly when one of those two is already in place. Fixing the lighting in your bedroom while sleeping six hours is solving the wrong problem.

• Keep the same rise time seven days a week, including weekends.
• Work out the bedtime that leaves enough hours, then defend it like an appointment.
• Get outdoor light early; it is far brighter than anything indoors and it anchors the clock.
• Leave a buffer before bed that is not work and not a bright screen at arm’s length.

What this section deliberately does not cover

Nothing here diagnoses anything. Insomnia that persists for weeks, loud snoring with pauses in breathing, sleepiness that makes driving unsafe, or a schedule you cannot shift no matter what you try are all worth taking to a doctor, and none of them are things a calculator can assess.

The line is drawn on purpose: timing and habits are useful and safe to work on yourself, while symptoms and conditions need someone who can examine you.

How much sleep do adults actually need?

The professional consensus figure is seven hours or more a night on a regular basis. It is a population floor rather than a personal number — some people do well slightly under it, and many people need more than seven and are running short.

Is it worse to go to bed late or to wake up at a different time each day?

An inconsistent rise time causes more trouble, because it keeps moving the body clock. A late but consistent schedule is easier to live with than a well-intentioned one that shifts by two hours every weekend.

Do naps make night sleep worse?

A short nap early in the afternoon usually does not. Long naps, or napping late in the day, eat into the pressure to sleep that has built up by bedtime, and that is when the night gets harder.