Why We Sleep

Matthew Walker is a sleep researcher and professor of neuroscience and psychology at the University of California, Berkeley, where he heads the Center for Human Sleep Science. In Why We Sleep (2017) he gathers the research on sleep into an accessible book for the general reader.

What the book covers

• What sleep actually is – the two main kinds, deep sleep (NREM) and dreaming sleep (REM), and how the sleep cycle and the circadian rhythm work.
• Why we dream, and the part dreams appear to play in memory and emotion.
• What happens when we sleep too little – for learning, memory, mood, the immune system, the heart and long-term health.
• Coffee and alcohol – how caffeine and alcohol affect sleep.
• Sleep across a lifetime – how sleep patterns change from childhood to old age.
• Practical advice for better sleep (sleep hygiene).

The central message is that sleep is one of the most undervalued things we can do for our own health – and that individuals and society alike ought to take it more seriously.

Worth knowing

The book is an engaging, well-written popular-science introduction, and a good place to start if you want to understand why sleep matters so much. Some of its most emphatic claims have been debated and criticised by other researchers, so read it as an inspiring way into the subject – not as the final word. The content is general knowledge and does not replace individual advice from a health professional if you have trouble sleeping.

The book was also published in Norwegian as Hvorfor vi sover (Forlaget Press, 2018).