Sleep is critical for rest and rejuvenation. A human being will actually die of sleep deprivation before starvation--it takes about two weeks to starve, but only 10 days to die if you go without sleep.
The CDC has also classified insufficient sleep as a public health concern. Those who don't get enough sleep are more likely to suffer from chronic diseases that include hypertension, diabetes, depression, obesity, and cancer.
It's thus vital to get enough shuteye, but it turns out your sleep position also has a significant impact on the quality of rest you get.
In addition to regulating one's appetite, mood, and libido, neuroscientists assert that sleep reenergizes the body's cells, aids in memory and new learning, and clears waste from the brain.
That last one is particularly important. Similar to biological functions in which your body clears waste, your brain needs to get rid of unwanted material. The more clearly it functions, the more clearly you do.
Now, a neuroscience study suggests that of all sleep positions, one is most helpful when it comes to efficiently cleaning out waste from the brain: sleeping on your side.
The study, published in the Journal of Neuroscience, used dynamic contrast-enhanced MRI to image the brain's "glymphatic pathway." This is the system by which cerebrospinal fluid filters through the brain and swaps with interstitial fluid (the fluid around all other cells in the body).
The exchange of the two fluids is what allows the brain to eliminate accumulated waste products, such as amyloid beta and tau proteins. What are such waste chemicals associated with? Among other conditions, Alzheimer's and Parkinson's.
"It is interesting that the lateral [side] sleep position is already the most popular in humans and most animals--even in the wild," said University of Rochester's Maiken Nedergaard. "It appears that we have adapted the lateral sleep position to most efficiently clear our brain of the metabolic waste products that build up while we are awake."
Sleeping on your side is good for more than just optimal brain functioning. It's helpful for those prone to snoring, those with obstructive sleep apnea, neck and back pain, and for pregnant women. The position elongates the spine, which helps with back pain, and mechanically opens the oropharynx, which can help with breathing.
For best results, sleep experts, chiropractors, and physical therapists recommend the following:
- Lie on your side, but not in the fetal position. (Some bending of the knees is fine, just not all the way up)
- Use an ergonomic pillow under your head, thick enough that your neck is supported
- Place a small pillow between your legs, such that your spine stays straight
Then, count sheep.
"I love sleep. My life has the tendency to fall apart when I'm awake, you know?" --Ernest Hemingway