How Sleeping on Your Side can Improve Your Health

Written by - Ali Gies, PhD in Physical Therapy

Side sleeping has typically taken a back seat to sleeping supine (on your back) as the healthiest sleep position. Both, however, are equally good for your health. While it may be easier to maintain spinal alignment when sleeping on your back, it is certainly possible (and fairly easy) to keep a neutral spine with side sleeping as well. Many people find it more comfortable, too. All you need are a few tips and tricks to ensure you’re getting the most benefit out of side sleeping. As we’ll discuss, side sleeping offers many health benefits that back sleeping does not, making it a great alternative to dozing off face up. 

Sleep Habits and Health

Do you suffer from brain fog, digestive issues, or chronic back pain? If so, how did you sleep last night, and the night before? Believe it or not, your sleep habits may be contributing to these and other health issues you never thought were related. Being a “good sleeper” does not necessarily mean you can sleep through a fireworks show outside. Sleep health is assessed using 2 measures: sleep quantity and sleep quality. 

  • Sleep Quantity
    • What do you consider a good night’s sleep? Five hours? Ten hours? While every person is different and has their own individual needs, current research indicates that the magic number to maintain healthy sleep habits is 7 hours of sleep each night [1]. Adults age 18-60 who get less than that are more likely to have diabetes, high blood pressure, heart disease, stroke, mental distress, and obesity [1]. In addition, they are more likely to get into car accidents, make medical errors, be involved in industrial accidents, and lose work due to poor mental performance [1]. 
    • To be clear, 7 hours isn’t the maximum amount of sleep you need to be successful. Some people, including many professional athletes, require much more sleep for physical and mental recovery. World Cup superstar and US Women’s National Team soccer player Alex Morgan credits her success on the field to getting between 9 and 10 hours of sleep every single night [2]. 
  • Sleep Quality
    • How well you sleep affects your health as much as how much you sleep. Quality sleep means that you fall asleep in 30 minutes or less, wake up no more than one time during the night, and fall back asleep within 20 minutes if you do awaken. If you don’t meet these criteria, chances are you’re not getting quality sleep. 

How Side Sleeping helps

  • Reduces back and joint pain
  • Reduces the effects of acid reflux
  • Decreases snoring
  • Helps mild sleep apnea
  • Boosts brain health
  • May reduce pain from fibromyalgia

When done properly, sleeping on your side can have many health benefits. It can reduce back and joint pain by unloading the spine when positioned correctly. In addition, it can reduce the effects of GERD (acid reflux) with similar results as sleeping with the head of the bed elevated [3]. In one study, sleeping in either position was more effective in reducing acid reflux than quitting smoking, eliminating alcohol, or changing diet [3].

Another benefit of side sleeping is it minimizes snoring, a common symptom of sleep apnea [4]. Sleep apnea is a potentially dangerous condition where breathing spontaneously stops and starts while sleeping. It can lead to other health issues like diabetes, high blood pressure, and fatigue.  In mild sleep apnea cases, side sleeping can be used as a conservative treatment to avoid using a CPAP (continuous positive airway pressure) machine every night [4]. 

Sleeping on your side has even been suggested to help with brain health. The brain has a ton of information to sort through every day. When you rest at night, it then must decide which pieces to keep and which to dump. When you lay on your side, your brain has an easier time removing interstitial waste, another name for material that the brain has labeled unnecessary to keep [5].

Left or Right?

Most studies support sleeping on the left side whenever possible. Our internal organs benefit the most from having the left side lower to the ground than the right during our “rest and digest” phase. The stomach, for instance, lies slightly to the left of center. Sleeping on the left side allows gravity to move contents through the stomach and into the colon quicker, aiding in digestion. The heart also lies to the left, so blood can be pumped in and out of it more easily when the muscles aren’t fighting gravity.  

Side Sleeping the Correct Way

There are a few important tricks to sleeping on your side correctly. The keys are adjusting the pillow to fit to your neck, not putting too much pressure on your shoulders, and keeping your spine neutral.

  • Head and neck
    • Keep the neck in a neutral position by placing one pillow underneath the side of the face and head. Pull the bottom of the pillow to meet the top of the shoulder. 
    • Next, grasp the bottom of the pillow and slightly bunch it up to fill in the space between the head and the shoulders. If you skip this step, you’ll likely have a tilt in your neck as you lay on your side, which often causes neck stiffness and soreness. Filling the gap helps keep the spine in a neutral position.
    • If you are positioned properly, your head and neck should feel comfortable and weightless.
  • Shoulders and arms 
    • Laying on your side can cause shoulder pain, both for the shoulder being laid on and for the one that is on top of the body.
    • Bottom arm
      • To avoid putting excessive pressure on the bottom shoulder, ensure that the arm is pulled out slightly and not directly underneath the rest of the body. Also, try not to sleep with it overhead or tucked under the pillow. This will result in waking up with a sore shoulder.
      • Bend the elbow slightly, but not excessively. Keeping the elbow completely bent for long periods compresses the ulnar nerve and will cause the arm to become numb and tingly. 
    • Top arm
      • The upper shoulder should rest comfortably on top of the body, not sitting too far forward or backward. Hugging a pillow with one or both arms can help with this. 
      • Keep the wrist in a neutral position, not bent forward or sideways. A common sleep complaint is waking up with “ants marching” on the forearms and hands. Keeping both the elbows and wrists in proper alignment will help avoid that. 
  • Back and hips
    • The low back is perhaps the most common source of pain during and after sleeping. Keeping it in a neutral position for as much of the night as possible will help reduce pain, allow it to heal if injured, and open up joint space for improved circulation.
    • When laying on the side with no support, the spine itself will be slightly side bent, which causes it to rotate relative to its natural position. This can cause irritation of the vertebral joints, decreased circulation, and joint stiffness. To correct this, place a pillow between the knees.
    • Allow one or both hips to flex forward slightly, and the knees will bend slightly as well. This opens up joint space in the lumbar spine, relieving compression from the day. 
    • A great deal of pressure is placed on the hips when laying on the side. The pillow between the knees helps minimize that pressure by distributing it more evenly. 
  • Feet and ankles
    • A trick that often gets missed with side sleeping is keeping the spine in neutral all the way down to the feet and ankles.
    • Ensure that the pillow placed between the knees either reaches all the way down to the feet (so there is space between the feet) or add another pillow between the feet.
    • The spine will be in slight torsion and the hips have excess pressure placed on them if the feet are not separate.


  1. Liu Y, Wheaton AG, Chapman DP, Cunningham TJ, Lu H, Croft JB. Prevalence of Healthy Sleep Duration among Adults--United States, 2014. MMWR Morb Mortal Wkly Rep. 2016;65(6):137-141. Published 2016 Feb 19. doi:10.15585/mmwr.mm6506a1.
  2. Bova, D. Alex Morgan’s Sleep Habits That Set Her Up For Success. Women Entrepreneur. Published June 12, 2019. Accessed October 21, 2020. 
  3. Kaltenbach T, Crockett S, Gerson LB. Are lifestyle measures effective in patients with gastroesophageal reflux disease? An evidence-based approach. Arch Intern Med. 2006;166(9):965-971. doi:10.1001/archinte.166.9.965.
  4. Brock E, Shucard DW. Sleep apnea. Am Fam Physician. 1994;49(2):385-394.
5. Lee, H, Xie, L et al. The effect of body posture on brain glymphatic transport. Journal of Neuroscience. 2015;35(31):11034-11044. doi:10.1523/JNEUROSCI.1625-15.2015.