Recently after pulling a couple 20-hour shifts, people kept encouraging me to sleep on my break. They were obviously concerned for my well-being but it got me thinking more about the role sleep plays in our lives. If the average life expectancy is 78 then we spend 30 percent of our lives asleep which is also the same amount we spend in our cars commuting, and a meager 0.16 percent making love.
We all know sleep refreshes and restores us, and in particular phases of sleep, our memories are reorganized and consolidated. But recent research has shown that during sleep our brains go into a self-cleaning mode.
For the body, waste clearance is handled by a second set of plumbing called the lymphatic system, a network of vessels which carries waste and byproducts from the tissue to the blood to be metabolized by the liver and eliminated. But the brain is so densely packed with cells and laced with a protective blood-brain-barrier that lymphatic system can’t penetrate and fit within the confines of the brain.
But then, how does the amazing and greedy organ such as the brain, which accounts for 25 percent of the body’s total energy consumption and is about 2 percent of the total body weight, clean its house?
Researchers discovered that during sleep the brain flushes out waste products via CSF and dumps them into blood vessels for removal. This is maximized during sleep. Typically CSF has been thought to hang out within the ventricular system inside the brain and spinal cord as well as the subarachnoid space.
But in sleep, CSF acts like draino, whereby it flushes out waste products between brain cells and goes deep into the brain parenchyma, not just pooling in the ventricles. And only during sleep, do glia cells, which support neurons, shrink, creating greater spaces between cells, allowing for greater fluid clearance and cleaning. This intricate cleaning design has been called the “gymphatic system.” What’s even more supernatural is that CSF goes deep into brain tissue hugging and following the brain blood vessels where the waste can be exchanged for removal. Since real estate is limited in the brain parenchyma, the brain’s blood vessels are our body’s form of minimalism because they perform double duty and save space: as a pathway to deliver nutrients to brain cells but also facilitate waste removal.
So the morals of the story are to have great sex since it’s so scarce in our lives and don’t judge people who drive fancy cars or those who’d rather sleep than party Friday night since a good chunk of our lives are attached to those activities and sleep is uber critical for health.
Jason Lee is a trauma and critical care nurse.
Image credit: Shutterstock.com