Why We Sleep
Why We Sleep
Last update 6 d. agoCreated on the 4th of May 2026

Why We Sleep

You are probably sleeping too little, and it is affecting everything. Matthew Walker has the data to prove it.

The Science of the Night

Matthew Walker's 2017 book synthesises decades of sleep research into an alarming and compelling argument that sleep is not optional downtime but the single most important health behaviour available to humans. He explains what happens during REM and non-REM sleep, what is lost when we deprive ourselves of both, and how every system from immune function to emotional regulation to memory consolidation depends on adequate rest. The book reads as both science and intervention.

journey·6 Parts

Reading Why We Sleep

Revelation

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What Sleep Is
Informative
"Two sleep types, a body clock, and a system far more complex than rest."
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Sleep is the single most effective thing we can do to reset our brain and body health each day.

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Matthew Walker

Walker is a professor of neuroscience and psychology at UC Berkeley. He has been scrutinised by other scientists for overstating some claims in the book, though the core argument about chronic sleep deprivation is broadly accepted.

The book became an international bestseller and has been cited in shifts to later school start times in several US states. It is credited with making sleep a public health conversation rather than just a lifestyle preference.