On the dance floor, each of us moves in a unique way, as if we came into the world pre-programmed with a certain movement style. The same thing holds true at bedtime. Some of us lay on our backs stiff as soldiers all night, others curl up fetal style, and yet others roll belly down.  It turns out that the sleeping position we opt for impacts health, plus, some experts think it reveals something about psychological makeup.

While most spinal health experts suggest that we should sleep on our backs, a recent study out of Stony Brook University in New York found a significant advantage to side sleeping. Apparently, those who sleep on their sides have a reduced risk of developing either Alzheimer’s disease or Parkinson’s.¹ TNJ Staff. “How Your Sleeping Position Can Reduce the Chances of Alzheimer’s.” 30 September 2015. The Network Journal. 26 November 2015. http://www.tnj.com/lifestyle/health-fitness/how-your-sleeping-position-can-reduce-chances-alzheimer%E2%80%99s     The benefit comes because the brain can remove waste more efficiently when turned on its side-at least, that was the case for the mice studied in this research.

Apparently, when we sleep, the brain goes to work doing housekeeping, getting rid of the byproducts of various metabolic processes, including proteins that otherwise would clog tissue and create the plaque that leads to cognitive degeneration.² Konnikova, Maria. “Goodnight. Sleep Clean.” 11 January 2014. The New York Times. 26 November 2015. http://www.nytimes.com/2014/01/12/opinion/sunday/goodnight-sleep-clean.html When we’re awake and thinking, this waste accumulates in brain pathways that are filled with cerebrospinal fluid, not moving anywhere. If enough of the waste remains stagnant, it can trigger the formation of plaque, which many suspect is a factor in triggering dementia. But during sleep, the brain pathways relax and expand by as much as 60 percent, which allows the fluid to start flowing, carrying waste out of the brain with it. Recent research indicates that this waste elimination process is one of the primary reasons we need to sleep.

The research showed that when the mice slept on their sides, that flow did happen more easily, and in fact, the side-sleeping mice removed brain plaque 25 percent more efficiently than the mice that slept on backs or bellies.³ “Sleep Position May Affect Brain Health.” 18 August 2015. Cognitive Therapeutics Method. 26 November 2015. http://cognitivetherapeutics.com/Newsroom/Blog/sleep-position-may-affect-brain-health/   The researchers used both MRIs and then later fluorescence microscopy and radioactive tracers to validate these findings.

So should you sleep on your side to ensure that you keep your brain fresh and young? According to many chiropractors and massage therapists, sleeping flat on the back, arms at the sides or folded on the belly, is the ideal position as it promotes spinal health. Your back is supported by the mattress and the neck remains in a neutral position. Back sleeping also may slow down the formation of wrinkles and pimples.⁴ “8 Sleeping Positions and Their Effects on Health.” 15 May 2013. Daily Health Post. 29 November 2015. http://dailyhealthpost.com/8-sleeping-positions-and-their-effects-on-health/ Plus, experts say, it’s the best position to minimize ac id reflux. “If the head is elevated, your stomach will be below your esophagus so acid or food can’t come back up,” says Dr. Eric Olson of the Mayo Clinic Sleep Center in Rochester, Minnesota.⁵ Walker, Mindy Berry. “Which sleep position is healthiest?” 19 April 2011. CNN. 1 December 2015. http://www.cnn.com/2011/HEALTH/04/19/healthiest.sleep.position/

To make back sleeping more comfortable and healthful for the spine, experts suggest using a cervical pillow under the neck or a bath towel rolled up and positioned under the neck instead of a traditional pillow. Also, it helps to have a small pillow under the knees to support the natural curve of your spine.

But back sleeping isn’t ideal–and not only because it ages the brain. For one thing, sleeping on the back exacerbates sleep apnea. A related issue is that people who sleep on their backs snore more, and their snoring is louder than those who choose other positions.

About 40 percent of us opt to sleep in the fetal position–it’s the most common position, particularly among women–with the head drawn down and knees tucked up, a posture not endorsed by many spinal health experts. Yes, curling up into a ball may let the cerebrospinal fluid flow and it sure is comfortable for many, plus it cuts back the snoring, but back sleeping advocates say it can wreak havoc on the spine and cause plenty of pain. Then again, other experts disagree and think it’s the best position for the spine.⁶ “The Best Sleep Positions.” The Doctor Oz Show. 9/27/2009 (Accessed 30 Nov 2015.) http://www.doctoroz.com/article/best-sleep-positions On the other hand, having the face squashed to the side promotes wrinkles, although there are side sleeping pillows that can alleviate that problem. Plus, side sleeping “might” exacerbate breast sag, something that back-sleeping theoretically avoids. Finally, some say the fetal position restricts diaphragmatic breathing, which can affect overall wellness and immunity.

If you’re going to sleep on your side, it’s better to uncurl a little and put your arms at your sides. Better yet, put a fairly thick pillow between your legs to reduce pressure on your hips and spine. Experts debate about which side is the best to sleep on. Some say choose the right because it will put less pressure on the internal organs. Others insist that the left is better because it will minimize acid reflux and encourage lymphatic drainage. According to Ayurvedic medicine, left-side sleeping will promote better digestion, better elimination, and better cardiac function.⁷ Douillard, John. “Amazing Benefits of Sleeping on Your Left Side.” 27 June 2013. Life Spa. 1 December 2015. http://lifespa.com/amazing-benefits-of-sleeping-on-your-left-side/

The worst position from the spinal point of view is sleeping on the stomach, a position preferred by about seven percent of the population. The problem is that this position requires that the neck be turned to the side, and inevitably, this will cause strain. Sleeping on the belly can relieve stomach distress, though, so it can be a good position to fall back on if you’ve eaten yourself sick.

Given all the variables, it does seem that the best option overall might be to sleep on your side with a pillow between your legs, making sure you don’t curve the spine fetal style. This position will protect the spine and the brain, even if it does, by some chance, make the skin and breasts sag.

By the way, while you’re reconsidering how you recline at bedtime, you might also want to look at the results of a study of 1000 people that concluded that sleep position indicates something about personality.⁸ “What Your Sleeping Style Says About You.” WebMD. 1 December 2015. http://www.webmd.com/sleep-disorders/features/what-your-sleeping-style-says-about-you For instance, those who sleep on their backs soldier style, arms at sides, tend to be easy-going and quiet, but sociable. Back-sleepers who put their arms up above their heads usually listen well, are willing to offer help, and don’t like to be the center of attention.⁹ “Sleep Positions.” The Better Sleep Council. 1 December 2015. http://bettersleep.org/better-sleep/sleep-positions Those who curl into a fetal ball come across as tough, but tend to be shy and soft on the inside. Sleepers who stay on their sides with their arms out in front of them are suspicious and cynical. And stomach sleepers are brash and resistant to criticism–yet another reason to flip to your side if you usually snooze belly down.