by Dr. Robert Rosenberg, medical adviser to SoClean
If you sleep comfortably through the night and wake up feeling refreshed, does it really matter what position you sleep in? Generally, my advice is "If it ain't broke, don't fix it," but there are some exceptions to that rule, as well as some interesting research about the pros and cons of various sleeping positions.
When it really matters
There are a few stages of life and health conditions where sleeping position truly does affect your health outcomes:
- If you're pregnant. There is evidence1 that side sleeping is best for the baby during the later stages of pregnancy—after about 28 weeks. Sleeping on the back can put pressure on a large blood vessel called the inferior vena cava and the mother's aorta, the main artery which carries oxygen-rich blood from her heart, reducing blood flow to the uterus and increasing the risk of stillbirth. (In early pregnancy, stomach sleeping is probably fine until the growing baby bump makes it uncomfortable.)
- If you are a baby. To help prevent sudden infant death syndrome, infants need to be placed on their backs2 to sleep. The incidence of SIDS fatalities has declined more than 50 percent since health officials started the Back to Sleep campaign recommending this position in the early 1990s.
- If you have back or neck pain. If you wake up with a sore back or neck, stomach sleeping is one of the worst positions—though you can try to make it more comfortable with a very flat pillow. If your severe back pain forces you to sleep on your back, try putting a pillow under your knees to achieve a more neutral spinal curve.
- If you snore or have a sleep disorder. Sleeping on your back lets gravity pull your tongue back into the pharynx and your jaw fall open, which can narrow your airway and worsen breathing issues and snoring.3
- If you have acid reflux. For reasons that aren't entirely clear,4 sleeping on your left side tends to improve acid reflux, while sleeping on your right side, back or stomach worsens it. Another sleeping position hack for acid reflux is to raise the head of your bed a few inches.
- If you're concerned about neurological disease. Sleeping on your side—either left or right—helps the body's glymphatic system be most effective at removing waste products from the brain5 at night. This nightly "cleanup" may help with the prevention of disorders such as Alzheimer's and Parkinson's disease.
How to change or adapt your sleeping position
There are a variety of ways to ease into a position that's better suited to your needs:
- To encourage side-sleeping while pregnant. One great solution is a full-body pregnancy pillow6 that both supports your uterus and keeps you safely on your side.
- To reduce snoring while on your back. If you love sleeping on your back, you may be able to reduce snoring and breathing problems with a wedge pillow7 that raises your head but still supports your shoulders.
- To discourage back sleeping. If you'd like to stay off your back entirely, or if a wedge pillow causes more back pain, you can try sewing a tennis ball into the back of a sleeping shirt—every time you roll onto your back, it will wake you up and you'll be forced to go back to your side. A couple of higher-tech solutions that do the same thing are the Night Shift8 and Zzoma9
- To discourage stomach sleeping. The tennis-ball trick just mentioned will work—just sew the ball into the front of your shirt instead of the back. To ease more gently into side sleeping from stomach sleeping, you can get a body-length pillow that will give you some pressure and support on your stomach as you sleep on your side. Or try a therapeutic or cervical pillow, which have a shape that will encourage side or back sleeping and discourage stomach sleeping.
- "Mega study confirms pregnant women can reduce risk of stillbirth by sleeping on their side," by Lesley McCowan and Robin Cronin, The Conversation, April 2019.
- "Sudden Infant Death Syndrome and Sleep," National Sleep Foundation, updated July 2020.
- "Why do you snore on your back?" Goodsomnia, September 2019.
- "The Claim: Lying on Your Left Side Eases Heartburn," by Anahad O'Connor, The New York Times, October 2010.
- "Side Sleeping May Clean Up ‘Mess' in Brains," by Lauren Sheprow-Stony Brook, Futurity, August 2015.
- "Best Pregnancy Body Pillows to Help You Sleep More Comfortably," by Jenn Sinrich, What to Expect, April 2020.
- "Best Pillows for Snoring," WebMD, accessed August 2020.
- Night Shift. Zzoma.