How sleep affects human health, explained

Editor’s note: This is part of a series called “The Day Tomorrow Began,” which explores the history of breakthroughs at UChicago. Learn more here.

All human beings need sleep. We spend a third of our lives asleep, and it’s as important as food, water or air to our survival. While scientists are still working to understand the exact nature of sleep and why it’s so important to our well-being, decades of research have made it clear that adequate sleep is vital to our physical and mental health. Among many other things, sleep plays a crucial role in memory consolidation and other brain functions, supporting the immune system and healing after injury or disease, and protecting against heart disease and diabetes.

How does sleep affect human health?

All human beings — and almost all animals — need sleep. We spend a third of our lives asleep, and it’s as important as food, water or air to our survival.

Typically, sleep is defined as an altered state of consciousness or a condition of the body and mind wherein the nervous system is less active, the body is relaxed, and consciousness is suspended. The definition of sleep may seem obvious — everyone knows the difference between being asleep and being awake. But scientifically and medically speaking, the term is less clear, and there is still a lot we don’t understand about the phenomenon.

While scientists are still working to understand the exact nature of sleep and why it’s so important to our well-being, decades of research have made it clear that adequate sleep is vital to our physical and mental health.

Researchers around the world — including those at the University of Chicago, home to the world’s first sleep research lab, opened in 1925 — have helped to clarify major questions about the biological functions of sleep, as well as its importance in consolidating memories and protecting the immune system, and the negative impacts of sleep deprivation.