Of all the remarkable things the human body does, sleep might be the most underappreciated. We spend roughly a third of our lives doing it, and for most of history we had no real idea why.
We now know considerably more — and what we've discovered should make all of us take sleep far more seriously than we do.
What Sleep Is Actually For
The popular notion that sleep is primarily about rest — that the body is simply powering down to recover — turns out to be dramatically incomplete. Sleep is an intensely active biological state, during which the brain and body are engaged in critical maintenance work that can't happen while we're awake.
During sleep, the brain consolidates memories — transferring information from short-term to long-term storage, and making connections between ideas that help with creativity and problem-solving. This is why studying before sleep is so much more effective than studying before a period of wakefulness, and why you sometimes wake up having "solved" a problem you were stuck on the night before.
The Glymphatic System
One of the most striking recent discoveries in sleep science is the glymphatic system — a network of channels surrounding the brain's blood vessels that, during sleep, flushes out metabolic waste products, including proteins associated with Alzheimer's disease.
In other words: sleep is, quite literally, how your brain cleans itself.
What Happens When We Don't Sleep Enough
The consequences of sleep deprivation are wide-ranging and significant. After 24 hours without sleep, cognitive function is impaired to an extent comparable to legal intoxication. After a week of sleeping six hours a night instead of eight, the cumulative effect is similar to a full night of sleep deprivation.
Dr. Amara Osei is the author of Science for the Curious, available now from Soulsprout Press.