We’re all familiar with the restorative role of sleep for the brain: Pulling an all-nighter or staying awake during a red-eye flight can not only change our mood but also affect our ability to think clearly until, at some point, it practically shuts down on its own. When we don’t get enough sleep, we’re simply not ourselves.
In the past five years, brain researchers have begun to expose a hidden world of chemical reactions, fluids flowing into and out of the brain, and the busy work of neurons that reveal the sleeping brain is as industrious as the waking one. Without good-quality sleep, those critical activities don’t take place, and as a consequence, we don’t just feel tired and cranky, but the processes that lead to certain diseases may even get seeded.
One of the reasons we sleep, it now seems, might be to keep a range of illnesses–including cognitive diseases like Alzheimer’s and other dementias–at bay. As Adam Spira, a professor in the department of mental health at the Johns Hopkins Bloomberg School of Public Health, puts it, “Sleep really should not be seen as a luxury or waste of time. People joke that they’ll sleep when they’re dead, but they might end up dead sooner if they don’t sleep.”
While medical experts have long recommended seven to eight hours of sleep a night–including some time spent in deep, or non-REM, sleep–exactly what our bodies are doing during that time is less clear. Now, thanks to newer technologies for measuring and tracking brain activity, scientists have defined the biological processes that occur during good-quality sleep. That they seem to be essential for lowering the risk of brain disorders, from the forgetfulness of senior moments to the more serious memory loss and cognitive decline of dementia and Alzheimer’s disease, may convince the busy bees of the world that sleep is not for the lazy.
For experts in the field of Alzheimer’s, the research is particularly exciting. There are currently no treatments for the neurodegenerative disease, and sleep-based strategies might open new ways to slow its progression in some and even prevent it in others.