---
type: literature
author: "Matthew Walker"
year: 2017
created: "2026-01-23"
tags:
  - sleep
  - neuroscience
  - health
---

# Why We Sleep

## Key Ideas

- Sleep is not passive downtime -- the brain is highly active during sleep
- [[Memory Consolidation]] occurs primarily during NREM sleep (facts) and REM sleep (skills, creativity)
- Sleep deprivation impairs [[Working Memory]], attention, and emotional regulation
- "Sleep on it" is literally good advice -- overnight processing improves problem-solving
- Learning before sleep is more effective than learning after waking for long-term retention

## Quotes

> "Sleep is the single most effective thing we can do to reset our brain and body health each day."

> "Practice does not make perfect. It is practice, followed by a night of sleep, that leads to perfection."

## Connections

- Directly informs the [[Memory Consolidation]] permanent note
- Sleep's impact on attention relates to [[Cognitive Load Theory]] -- tired brains have less capacity
- The creativity benefits connect to diffuse thinking and [[Flow State]]
- Challenges purely wake-centric views of [[Spaced Repetition]] scheduling
- Essential reading for [[Effective Study Habits]]

#neuroscience #sleep #health
