Side sleeping is the most popular sleep position. And yet, it’s easy to do it in a way that causes shoulder, hip, and back pain in the morning. Perhaps you fall asleep with your arms under your pillow, only to wake in the middle of the night because your arms have grown numb.
If you’re a side sleeper, improving your position will allow you to better reap the benefits of your sleep position—healthier heart, reduced snoring, and lowered chances of developing a neurodegenerative disease.
Side Sleeping Positions
Side sleeping is a broad term since side sleepers tend to position their arms and legs differently. We can break side sleeping down into four different variations:
- Fetal: The fetal position is the most common side sleeping position. In the fetal position, you draw your knees close to your chest, curling your back into an arch.
- Log: In the log position, your legs are straight, and your arms kept at your sides.
- Yearner: If you’re a yearner, you sleep with your arms stretched out, while your back and legs remain straight.
- Sprinter: Sprinters sleep with one leg bent at the knee while the other leg is kept straight.
There’s even variations of all four positions—for example, you might be a yearner who sleeps with a bent leg. You’re also likely to move throughout the four as you sleep.
Benefits of Side Sleeping
Side sleeping can alleviate various medical conditions: congestive heart failure, sleep apnea, and acid reflux. It may also prevent the development of neurodegenerative diseases such as Alzheimer’s.
There’s evidence that sleeping on your right side promotes a healthy heart. A 2003 study examined 75 patients with congestive heart failure, along with 75 control subjects. The patients avoided sleeping on their left sides because of discomfort—a discomfort they didn’t feel sleeping on their right side.
Why is the right side more comfortable for the heart? Since your heart is on the left side of your body, sleeping on that side presses your heart against the chest cavity. Right side sleeping puts no extra pressure on your heart.
Side sleeping also reduces your sympathetic nervous system activity. The sympathetic nervous system controls your “flight or fight” response, preparing your body for physical activity—which includes your heart because it’s the organ that’s pumping blood throughout the body to meet physical demands. Right side sleeping lowers your heart rate and blood pressure, calming you.
Cleans Out Brain Waste
Scientists just recently discovered the glymphatic system, so there’s still much to learn about it. The glymphatic system eliminates waste compounds from your nervous system and may assist in distributing other compounds such as glucose, amino acids, and neurotransmitters in the brain. Researchers theorize that the glymphatic system works to prevent neurodegenerative diseases, as diseases such as Alzheimer’s are characterized by waste protein build-up.
Your glymphatic system operates mostly while you’re asleep, so a 2015 study sought to determine if sleeping positions had any effect on how well it worked. Researchers examined MRI images of side, back, and stomach sleepers, and discovered side sleeping had “a clear advantage” when it came to how well the glymphatic system removes waste products.
The improved efficiency of your glymphatic system might be because blood flow to the head increases when you’re lying on your side, as a 2019 study hypothesized.
Soothes Snoring and Sleep Apnea
If you have a bed mate or household member who complains about your snoring, try sleeping on your side. Side sleeping keeps the airway open by preventing the collapse of soft tissue at the back of your throat—a common problem if you sleep on your back.
Side sleeping can also alleviate obstructive sleep apnea, a condition where your breathing slows or stops multiple times throughout the night. When you have sleep apnea, you can get a full night’s sleep and still feel tired the next morning because of reduced sleep quality. Your doctor is likely to recommend side sleeping along with CPAP therapy and other lifestyle changes such as weight loss.
Reduces Acid Reflux
If you’re lying down on your back, gravity can exert pressure on your stomach, letting stomach acid flow freely up to your esophagus. Acid reflux can give you persistent heartburn, bad breath, nausea, and chest pain.
Acid reflux and the more permanent condition GERD can damage the esophagus. In rare cases, the lining of your esophagus can change, becoming more like the tissue in the small intestine, known as Barrett’s esophagus. GERD can also wear away at your teeth.
Side sleeping can prevent stomach acid from flowing up the esophagus. Additional measures, such as raising your bed and losing weight, also keep stomach contents in place.
Improves Blood Flow in Pregnant Women
Side sleeping is usually the only comfortable way a pregnant woman can sleep by her third trimester. The left side is generally favored over the right, as it increases blood flow to the fetus and improves the woman’s kidney function.
Drawbacks to Side Sleeping
Nothing is without its downsides, and that includes side sleeping. However, you can alleviate most issues with the right mattress and pillow.
Shoulder and Hip Pain
Sleeping on your side concentrates pressure on your shoulders and hips. If left alone, the pressure will build into pain, and you will wake with sore shoulders and hip pain. Worse, if the pressure isn’t being released, it’s likely your mattress isn’t conforming well enough to maintain neutral spine alignment—so you may wake up with a sore back as well.
Often, the solution is simple if somewhat costly—get a better mattress. The best mattresses for hip pain keep the hips aligned with the rest of your spine, while also providing pressure and pain relief—soft, thick comfort layers are the best for easing pressure in your shoulders and hips. If you can’t afford a new mattress, a soft mattress topper can make your current mattress more comfortable.
Most of us are familiar with the “pins and needles” feeling we get when our legs or arms fall asleep. The scientific term for this is “paresthesia,” and it often occurs simply from holding one position for a considerable length of time. For example, sitting in a car for hours can cause your legs and buttocks to go numb.
More severe causes of paresthesia can include nerve damage or pressure on a nerve from something such as a herniated disc, enlarged blood vessels, or infection.
Many side sleepers struggle with how to place their arms comfortably, causing them to wake up with numb hands and fingers. To avoid paresthesia, avoid falling asleep with your arms stretched above your head, folded under your head and pillow, or bent, as all of these positions cut off blood circulation.
Acne and Wrinkles
Pressing your face into your pillow night after night can take a toll on your skin. Wash your pillowcase every week with your bedding to prevent a build-up of oils and other debris that can cause acne. Instead of sleeping on a soft pillow, try a firm pillow that contours less to your face. Similarly, a pillowcase with a slippery surface (such as silk or satin) may not press as much against your face as a cotton or flannel pillowcase.
Which Side: Right or Left?
Both sides are not equal when it comes to side sleeping, mainly because your body is not symmetrical.
We recommend sleeping on the right side since it may be the key to a healthier heart. Studies suggest it reduces pressure on the heart and stabilizes your blood pressure and heart rate.
Does that mean sleeping on your left side is bad for your heart? Not necessarily, as the previously mentioned 2003 study shows.
Remember that the study examined both subjects with congestive heart failure and perfectly healthy subjects. The control subjects with healthy hearts freely slept on their left and right sides. It’s just that right-side sleeping helps your heart perform better, which is excellent for anyone with a heart condition.
Pregnancy is an exception to the “right side is better” rule, as blood flow from the mother to the fetus improves when the mother sleeps on her left side.
Sleeping on the Right Mattress and Pillow
Despite the health perks of sleeping on your side, you won’t get a good night’s rest if you aren’t sleeping on the right mattress with a good pillow.
A good mattress for a side sleeper should have a thick comfort layer to fully conform around the hips and shoulders. The mattress should have a soft to medium feel, as a too firm mattress aggravates pressure points.
We strongly recommend side sleepers stay away from innerspring mattresses, as the thin comfort layer can’t sufficiently contour to the body for pressure relief. Instead, we suggest looking at memory foam mattresses, latex mattresses, and hybrid beds.
Side sleeping is the position that creates the most distance between your neck and sleeping surface, so you need a thick, firm pillow for neck support. A too-thin pillow will cause your head to sag, straining your neck and causing neck pain. Look for a pillow between 4 to 6 inches thick.
Other Sleeping Positions
While side sleeping has a lot of health benefits, it isn’t necessarily the best sleeping position for everyone.
Back sleepers place the least amount of stress on their spine, as posture and even distribution of pressure keep the spine in the neutral position. The main disadvantage of back sleeping is the risk of snoringas gravity collapses the soft tissue at the back of your throat.
Stomach sleepers are at risk of lower back pain, as the position overextends the spine out of its natural curve. We strongly recommend switching to side sleeping if you’re a stomach sleeper. Sleeping with a body pillow or attaching a tennis ball to the front of your sleepwear (to prevent you from rolling onto your stomach) can help you make the change.
Frequently Asked Questions
Are memory foam mattresses good for side sleepers?
Yes. We highly recommend memory foam mattresses for side sleepers, as the material cradles the hips and shoulders for pressure relief. Memory foam is also a good choice for anyone who’s sharing a bed or has allergies, as the material isolates motion and is dense enough to keep out most allergens.
Is a firm mattress good for side sleepers?
A firm mattress is likely to leave a side sleeper with hip and shoulder pain, as it lacks the contouring needed to relieve pressure. Instead, side sleepers should look for mattresses with a soft to medium feel.
What is the best pillow for a side sleeper?
The best pillows for side sleepers are firm and lift the head and neck to maintain spine alignment. The pillow should be 4 to 6 inches thick. Side sleepers also benefit from tucking a pillow between their legs to maintain hip alignment, and some find hugging a small pillow keeps their arms from falling asleep.
Did We Help?
Side sleeping reduces pressure on your heart, alleviates symptoms of acid reflux and sleep apnea, and helps your brain work more efficiently. However, you need an excellent mattress to alleviate pressure in your shoulders and hips and should position your arms, so they don’t fall asleep while you’re sleeping. That’s a small price to pay for waking up refreshed and rested.
This article is for informational purposes and should not replace advice from your doctor or other medical professional.