Why We Sleep

Walker presents his primary argument: Sleep loss is an epidemic, and the greatest public health challenge faced by modern society in the past century. Researchers considered sleep to be “one of the last great biological mysteries” (5), but the advent of brain-imagining machines in the early-21st century led to major scientific breakthroughs. These recent discoveries in the field of sleep health illustrate that sleep deprivation (or less than eight hours of sleep a night) has catastrophic health and well-being consequences.

Despite the overwhelming evidence that supports adequate nightly sleep, adults in developed nations do not obtain the “recommended eight hours of nightly sleep” (3). To Walker, society’s indifference towards sleep is due to scientists, government officials, and policymakers failing to explain the reasons why we need it and prioritizing policy around it. Walker hopes that readers gain an appreciation of sleep and reverse their own and their families’ neglect of it. 

Walker explains in detail the “two main factors that determine when you want to sleep and when you want to be awake” (13). The first factor is known as the circadian rhythm, which is a natural process generated by the