Science of Sleep
You can’t improve what you don’t understand. This part covers the biology of sleep—what actually happens while you’re unconscious, what drives your sleep timing, and what goes wrong when the system breaks down.
1
Why Sleep Matters
Sleep is not downtime—it’s when your brain consolidates memory, your body repairs tissue, and your hormones reset.
2
Sleep Architecture
The structure of a night’s sleep: 90-minute cycles, NREM stages, REM, and how they change across the night.
3
Circadian Biology
The internal clock that governs your sleep timing—and the environmental cues (zeitgebers) that set it.
4
Chronotypes
Why owls and larks exist, what social jet lag costs you, and why willpower can’t override your biology.
5
What Goes Wrong
The biological mechanisms behind the four most common sleep problems.