This complete book comes from a public-domain NIH lecture. Open a chapter and see how the explanations and slide figures come together.
Chapter Three
A human cell: the nucleus holds the genetic code that keeps the body’s clock in time.
Nearly every cell keeps its own clock, wound each day by light and synced to a master timer deep in the brain — which is why sleep is never only about the hours you spend in bed.
An NIH Scientist’s Guide to Sleep, Circadian Timing, and Cardiovascular Health
Generated from “The Role of Sleep in Health,” a public-domain NIH VideoCast lecture.
These diagrams and charts come from the slides in the sample lecture. Open the chapter to see them in context.
A Venn diagram of the three overlapping families of sleep disorders, with the slide labels retained.
A survival-probability chart linking sleep-apnea severity to long-term mortality risk, with its axes and legend.
A human-cell diagram with labels for the nucleus, mitochondria, and protein-synthesis machinery.
The daily sleep-wake rhythm shows how sleep drive and sleep need change across twenty-four hours.
How light, sleep, diet, and exercise combine to support health and resilience.
Each link opens the full chapter. Read as much as you like without an account.
The body’s inner clock
Read the lecture's explanation of the body clock in sections, with the slide diagrams beside it.
The daily sleep-wake rhythm, carried into the chapter with its labels intact.
Sleep timing, the heart, and sleep apnea
Work through the lecture's charts and clinical definitions in readable prose.
A survival-probability chart linking apnea severity to long-term mortality risk.
Sleep disorders and the bigger picture of health
Follow the lecture's account of sleep disorders, with its Venn diagram in the chapter.
The sleep-disorders Venn diagram, with the three overlapping families and their labels.
Try 15 minutes once. No card required.