Side Sleeping: Which Side Should You Sleep On?

The Best Side to Sleep On

For most people, there’s no significant difference between right-side sleeping versus left-side sleeping. Trusted Source Work View Source Both positions can support proper spinal alignment, provided you have the right pillow and mattress. 

That said, sleeping on one specific side might be better for people with specific health concerns, such as those who are pregnant or those with heartburn, shoulder pain, or heart conditions.

• During Pregnancy: As pregnancy progresses, experts strongly recommend sleeping on the left side. Trusted Source Medline Plus MedlinePlus is an online health information resource for patients and their families and friends. View Source While occasional right-side sleeping is fine, experts caution against sleeping on your back during the second and third trimester. Trusted Source American College of Obstetricians and Gynecologists (ACOG) ACOG is a membership organization dedicated to the advancement of women’s health care through continuing medical education, practice, and research. View Source
• If You Experience Heartburn: Experts usually recommend elevating the head of the bed if you have heartburn. Trusted Source National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) NIDDK research creates knowledge about and treatments for diseases that are among the most chronic, costly, and consequential for patients, their families, and the Nation. View Source However, there’s also evidence that left-side sleeping may help curb acid reflux symptoms. Trusted Source The American Journal of Gastroenterology View Source
• Those With Heart Conditions: People with heart failure sometimes find they experience shortness of breath when lying on their left side but not on their right side. Trusted Source Echocardiography View Source
• If You Have Shoulder Pain: People with shoulder pain may find themselves naturally sleeping on the pain-free side. Trusted Source BMC Musculoskeletal Disorders View Source

Benefits of Sleeping on Your Side

Both right- and left-side sleeping may have benefits for spinal alignment, breathing, and brain functioning.

Neck and Back Pain Relief

Many people live with chronic neck or back pain. Trusted Source BMJ Open View Source Research suggests side sleeping, particularly symmetrical side lying, can reduce pain in the back and neck. Trusted Source Cureus Journal of Medical Science View Source  

However, the best sleeping position for back and neck pain may vary depending on your specific symptoms. Trusted Source Cureus Journal of Medical Science View Source Back sleeping may or may not help reduce lower back pain, while stomach sleeping is generally considered to increase the amount of pressure on your spine and lead to pain upon waking. 

Reduced Risk of Snoring and Sleep Apnea

People tend to snore more when sleeping on their backs instead of their sides. When you sleep on your back, it’s easier for your tongue to fall back into your throat, creating an obstruction that can result in snoring.

When you sleep on your side, your airway may stay more open, so you can breathe easier. For this reason, physicians recommend people with position-dependent sleep apnea, a sleep-related breathing disorder, sleep on their side to help relieve symptoms. Trusted Source European Journal of Heart Failure View Source Trusted Source Merck Manual First published in 1899 as a small reference book for physicians and pharmacists, the Manual grew in size and scope to become one of the most widely used comprehensive medical resources for professionals and consumers. View Source

Additionally, symptoms of central sleep apnea — a type of sleep apnea that often accompanies heart failure — are much better when sleeping on either the left or the right side rather than the back. Trusted Source Sleep Medicine View Source Trusted Source Sleep and Breathing View Source

Healthier Pregnancy

Side sleeping is recommended for pregnant people Trusted Source Medline Plus MedlinePlus is an online health information resource for patients and their families and friends. View Source , because it’s easier for the heart to pump blood through the body in this position. Side sleeping also prevents the baby from putting too much pressure on the vena cava, the largest vein in the body. And left-side sleeping, in particular, exerts less pressure on the liver and increases blood flow to the fetus and kidneys.

Side sleeping is considered safer during pregnancy, since back sleeping is associated with an increased risk of late stillbirth in some studies. It may also help prevent or relieve pregnancy-associated back pain.

Decreased Risk of Heartburn

Sometimes called acid reflux, heartburn occurs when the esophagus opens and allows partially digested food and stomach acid to move back up the esophagus. Trusted Source National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) NIDDK research creates knowledge about and treatments for diseases that are among the most chronic, costly, and consequential for patients, their families, and the Nation. View Source This causes an acidic burning sensation or pressure in the chest. Trusted Source National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) NIDDK research creates knowledge about and treatments for diseases that are among the most chronic, costly, and consequential for patients, their families, and the Nation. View Source People who regularly experience these symptoms may be diagnosed with gastroesophageal reflux disorder (GERD).

Sleeping on the left side keeps the esophagus positioned slightly higher than the stomach, which encourages digested food to continue moving through the digestive tract instead of backing up into the esophagus. Trusted Source World Journal of Clinical Cases View Source

Potentially Improved Brain Health

During deep sleep, the brain’s glymphatic system flushes out toxic waste products. Trusted Source Journal of Neurophysiology View Source These waste products build up throughout the day as a by-product of metabolism, and a failure to properly clear them out is linked to the development of neurodegenerative diseases. 

Animal studies suggest that side lying is the best position for glymphatic functioning Trusted Source The Journal of Neuroscience View Source , though human studies are needed to confirm this finding. Trusted Source The Journal of Neuroscience View Source

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Tips for Side Sleeping

Your sleep position is just one part of the overall sleep setup. You can get the most out of side sleeping if you choose the right mattress and pillows and make some tweaks to the exact side sleeping position.

Get Into a Symmetrical Side Sleeping Position

Symmetrical side sleeping supports the natural curvature of your spine and may be less likely to cause back and neck pain.

1. Lie on your side with your head on the pillow.
2. Ensure your chin and neck are aligned in the center of your shoulders, and your shoulders are in line with your hips.
3. Keep your head looking forward, so your chin doesn’t tilt down to your neck or twist to the side.
4. Keep your arms and hands aligned with each other, either by your sides or slightly in front of you.

Many side sleepers opt for a fetal position, with their legs bent and curled in toward their chest. This position can relieve pressure in the lower back and is often preferred by people with chronic lumbar pain. Trusted Source Brain and Spine View Source  

“Your sleeping position can change throughout the night. Allow yourself freedom of movement and your body will naturally find the best position without disturbing your sleep.”

Brandon R. Peters, MD, FAASM

Sleep Physician, Sleep Psychiatry Expert

Pick a Mattress That Supports Side Sleeping

The best mattresses for side sleepers tend to be medium or medium firm, a 5 or 6 on a scale of 1 to 10 with 10 being the firmest. These mattresses cushion hips and shoulders while maintaining spinal alignment. Trusted Source Sleep Health View Source Trusted Source Sleep Science View Source

Your mattress and pillow should evenly distribute your weight while supporting a neutral position for your neck and torso. Trusted Source Bioengineering (Basel) View Source The right mattress for you depends on factors like your body shape, your weight in addition to your typical sleep position.

For side sleepers, mattresses that are too soft may fail to support weight-bearing areas like the hips, allowing them to sink in too far and pull the spine out of alignment. Mattresses that are too firm don’t provide enough cushioning. Not only can this cause sore hips and shoulders, but it can also allow a gap to form between your waist and the mattress surface. If your abdomen sinks down to fill this space, it can also lead to discomfort and spinal misalignment.

Get a Pillow Designed for Side Sleepers

A supportive pillow reduces strain on the neck and plays an important role in preventing neck pain. Trusted Source Medical & Biological Engineering & Computing View Source Ideally, the pillow should fill in the space between your head and the mattress to keep your head aligned on an even plane with your spine. Trusted Source Journal of Physical Therapy Science View Source Since the shoulders raise the head further from the bed when side sleeping, side sleepers usually do best with a thicker pillow.

An unsupportive pillow may cause morning aches and pains, or even headaches. Firmer materials like latex are considered more effective at providing neck support, although the most important factors are the pillow’s shape and height, or “loft.” Trusted Source Clinical Biomechanics View Source Using a supportive pillow can also keep weight off the shoulders to reduce pressure buildup if you have shoulder pain. Trusted Source Cureus Journal of Medical Science View Source  

If you struggle to find a supportive pillow, you may prefer a cervical pillow, which has a higher part to support the neck and a lower loft under the head. Studies on back sleepers suggest this design helps keep the head and neck at approximately the same natural angle as they would be when you are standing up.

Consider Using a Knee Pillow

One major problem with side sleeping is that the upper leg — the one furthest from the bed —  collapses onto the lower leg and causes the spine to twist. Placing a small pillow or a rolled-up towel between your knees can help relieve pressure on the hips and prevent your knees from collapsing onto each other. Trusted Source Work View Source Placing your arms and legs strategically can also help stabilize you when side sleeping. 

Pregnant people may find it helpful to place an additional pillow in the small of the back or under the abdomen or use a full-body pillow.

When to Consider a Different Sleeping Position

Side sleeping has benefits, but it’s not for everyone. People with chronic pain or aesthetic concerns may prefer back sleeping. If you’re unsure what sleeping position is best for your medical issues, talk to your doctor. 

• You Have Sore Shoulders or Sore Hips: When lying on your side, the shoulders and hips bear the brunt of your weight where you contact the mattress, causing pressure points and potentially exacerbating pre-existing shoulder or hip pain. If you’ve tried a softer mattress with no improvement, you may find it more comfortable to sleep on your other side or try back sleeping.
• You Live With Back or Neck Pain: While the ultimate goal is to keep the spine on an even plan, the best sleeping position for back and neck pain can vary from person to person. While some people are comfortable side sleeping, others find it more comfortable to roll onto their back, sometimes with a thin pillow under the lumbar area. Experts do generally recommend against stomach sleeping, which is hard on the spine.
• You’re Concerned About Wrinkles: Sleeping on your stomach or side with your face pressed into the pillow can compress and stress your skin, leading to wrinkles Trusted Source Aesthetic Surgery Journal View Source . If you’re worried about wrinkles, sleeping on your back allows you to reduce this wrinkle-causing pressure.

If you switch from side to back sleeping, a thinner pillow may help support your new sleep position. Look for a medium-loft pillow that’s high enough to provide cushioning for the neck when back sleeping but not so high that it causes your chin to tilt forward into the chest.

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