The problem this solves
Most sleep advice is upside-down. People reach for supplements and wearables before fixing timing, light, caffeine, and environment — the four levers that actually move the needle for almost everyone.
This micro-course teaches the four levers in order, then deals with the wider edges (alcohol, evening exercise, hot bedrooms, devices). It rejects the supplement-led framing the wellness internet leans on. By the end you have a sleep system that survives travel, deadlines, and bad weeks.
A taste of the exercise
The preview lesson walks you through picking a fixed wake time and front-loading the day with 10-15 minutes of outdoor light. Both interventions are free, run for years, and are the highest-leverage changes most adults can make in week one.
Key concepts
- Circadian rhythm
- The body's ~24-hour internal clock, entrained primarily by light and consistent timing.
- Social jet lag
- Shifting your sleep phase 1-3 hours on weekends; biologically equivalent to flying across timezones twice a week.
- Sleep pressure (adenosine)
- The chemical drive to sleep that builds during waking hours. Caffeine blocks it; sleep clears it.
- Sleep efficiency
- Time asleep divided by time in bed. High efficiency from a regular schedule beats long, irregular nights.
- Bedtime drift
- The number of minutes your bedtime varies night to night. Lower is better; under 30 minutes is excellent.
- Caffeine half-life
- 5-7 hours in average adults, longer in slow metabolisers. A 3pm coffee can still be active at 11pm.
Common mistakes
- Optimising supplements before timing, light, caffeine, environment.
- Catching up at weekends and creating social jet lag.
- Charging the phone next to the bed.
- Forgetting tea counts as caffeine.
- Working in bed; weakening the “bed = sleep” cue.