The short answer: there is no single best sleep position for everyone. The right position depends on your age, health conditions, and personal comfort. That said, most sleep experts agree that side sleeping offers the widest range of benefits for the average adult, while stomach sleeping is the most problematic for spinal health.
Sleep occupies roughly one-third of your life, and the position you choose can influence everything from back pain to breathing, digestion, and even brain health [1][6]. Yet the “best” position is not a one-size-fits-all answer. A position that relieves one person’s back pain may worsen another’s sleep apnea.
This article breaks down what the latest research and clinical guidance say about each major sleep position, who benefits most from each, and how to make adjustments if needed.
Why sleep position matters
Your body is not inert while you sleep. The mechanical stress placed on your joints, muscles, and airways during those hours accumulates. Poor sleep posture has been identified as a leading contributor to morning stiffness and aches, sometimes called “waking spinal symptoms” [6].
The goal of any sleep position, from a musculoskeletal perspective, is neutral spinal alignment: keeping your ears, shoulders, and hips in a relatively straight line [6]. This minimizes strain on joints and ligaments. But alignment is only part of the picture. Sleep position also affects how easily you breathe, how well stomach acid stays down, and how efficiently your brain clears waste products.
Side sleeping: the most widely recommended position
Sleeping on your side is the most popular position among adults, and it is generally considered the best default for most people [4][13]. It offers several documented advantages.
Breathing and sleep apnea
When you lie on your back, gravity pulls your tongue and jaw backward, narrowing the upper airway. This can cause snoring and worsen obstructive sleep apnea [1][2]. Side sleeping helps keep the airway open and reduces breathing disruptions [13]. For people with mild sleep apnea, positional therapy (training yourself to sleep on your side) can be a meaningful intervention [13].
Digestion and acid reflux
Sleeping on your left side specifically may reduce symptoms of acid reflux and gastroesophageal reflux disease (GERD). The stomach sits on the left side of the body, and lying on the left keeps it below the esophagus, making it harder for acid to travel upward [3][7]. Right-side sleeping, by contrast, can worsen heartburn [3].
Pregnancy
Medical providers routinely recommend side sleeping during the later stages of pregnancy, particularly the third trimester [1][2]. The left side is usually preferred because it keeps pressure off the inferior vena cava, a large vein that returns blood from the lower body to the heart [2][16]. Compressing this vein can reduce blood flow to both the mother and the fetus.
Back and neck pain
Side sleeping can help alleviate back pain, especially when you place a pillow between your knees [2][11]. This keeps your hips and pelvis aligned and prevents your top leg from pulling your spine out of neutral. A pillow height of 7 to 11 centimeters is shown to best maintain the cervical curve when side sleeping [6].
Brain health
Preliminary research with animals suggests that side sleeping may support the brain’s waste clearance system, known as the glymphatic system [7][16]. Compared to back or stomach sleeping, the lateral position was shown to be more effective at removing toxins from the brain, which may reduce the risk of neurodegenerative conditions like Alzheimer’s disease [16]. This research is early, but it is one of the more intriguing findings in sleep science.
Drawbacks
Side sleeping is not perfect. It can increase pressure on the shoulder, which may be problematic for people with shoulder pain [15]. Without proper pillow support, the top leg can fall forward and twist the pelvis, pulling on the lower back [6]. Rotating sides during the night can help prevent overuse of one shoulder or hip [19].
Back sleeping: good for the spine, bad for breathing
Sleeping on your back, also called the supine position, is often described as the “gold standard” for spinal neutrality [6]. It allows for the most even distribution of body weight and minimizes spinal deviation [6].
Who benefits most
Back sleeping can be helpful for people with certain types of back pain. Placing a small pillow under your knees reduces lumbar lordosis (the arch in your lower back) and takes pressure off your lumbar discs and facet joints [6][11]. It is also a good option for people with hip or knee pain [10].
For people concerned about facial wrinkles, back sleeping is the best choice because your face is not compressed against a pillow [3]. Over time, side and stomach sleeping can create sleep lines and chronic skin changes [3][8].
Who should avoid it
Back sleeping is generally the worst position for people who snore or have sleep apnea [2][13]. When you lie on your back, gravity causes the tongue and soft tissues to collapse backward and narrow the airway [1][2]. Studies show that breathing disruptions in both obstructive and central sleep apnea occur more frequently when sleeping on the back [13].
If you have acid reflux, sleeping flat on your back can also worsen symptoms [1]. Elevating your head with a wedge pillow or adjustable bed can mitigate this, but side sleeping is usually a better choice [13].
Note on sleep paralysis: Research has found that sleep paralysis episodes are more common when people sleep on their backs [18]. The supine position was reported three to four times more frequently during sleep paralysis than when normally falling asleep [18]. If you experience recurrent sleep paralysis, switching to side sleeping may reduce episodes [9].
Stomach sleeping: generally discouraged
Sleeping on your stomach, or the prone position, is the least recommended position by healthcare providers [6][8][17]. While it can help keep the airway open and reduce snoring, the musculoskeletal costs usually outweigh the benefits.
Spinal strain
Stomach sleeping flattens the natural curve of your spine and puts added stress on your lower back [8][17]. It also forces you to rotate your neck to one side to breathe, which strains the cervical spine and surrounding tissues [8]. Over time, this prolonged twisting can contribute to chronic neck pain and spinal misalignment [17].
Shoulder and arm problems
When you sleep on your stomach, your arms are typically raised above your head or tucked under a pillow. This positioning puts tension on the shoulder joint and can eventually lead to rotator cuff problems or other shoulder issues [8].
When stomach sleeping might help
There is one scenario where stomach sleeping may offer relief: for some people with mild sleep apnea, lying face down can help keep the airway open [13]. However, the evidence is mixed and limited, and stomach sleeping makes using a CPAP machine difficult because the mask can shift or press into your face [13]. If you have sleep apnea, side sleeping is generally a better solution.
If you cannot sleep any other way
For people who find stomach sleeping the only comfortable option, some adjustments can reduce strain. Placing a pillow under your pelvis and lower stomach can prevent your lower back from sagging into a painful arch [6][11]. Using a very thin pillow under your head, or none at all, reduces the angle of neck rotation [6].
Special considerations
Pregnancy
Side sleeping is recommended for all trimesters, but it becomes especially important in the third trimester [2][17]. Sleeping on your back during late pregnancy can cause the uterus to compress the inferior vena cava, reducing blood flow to the heart and fetus [2]. The left side is usually preferred, though brief periods on the right side are acceptable to relieve pressure on the left hip [15].
Infants
The recommendation for infants is unequivocal: babies should always be placed on their backs to sleep [12][14]. This is one of the most well-established findings in pediatric sleep medicine and has been credited with significantly reducing sudden infant death syndrome (SIDS) rates. The American Academy of Pediatrics emphasizes the “ABCs” of safe sleep: Alone, on the Back, in a bare Crib [12]. Stomach sleeping for infants is dangerous and should never be done [8][14].
Sleep apnea
For adults with obstructive sleep apnea, side sleeping is the preferred position [13]. If you use a CPAP machine, side sleeping is also more compatible with the mask than stomach sleeping [13]. For people who cannot tolerate CPAP or positional therapy, sleeping with the head elevated at a 60-degree angle may be a compromise [13].
Acid reflux and GERD
Left-side sleeping is the best position for managing acid reflux [3][7]. Sleeping on the right side or on the back can worsen symptoms [1][3]. If you must sleep on your back, elevating your head can help [13].
Can you change your sleep position?
Changing a lifelong sleep habit is not easy. You may fall asleep in a new position and revert to your old one during the night. Experts say it can take several weeks of consistent effort [1].
A few strategies may help:
- Pillow support: Place a pillow between your knees for side sleeping, or under your knees for back sleeping [1][6]. A full-length body pillow can make side sleeping more comfortable and prevent rolling onto your back [9].
- The tennis ball technique: Sew a tennis ball into the back of your pajama shirt. When you roll onto your back, the discomfort prompts you to shift back to your side without fully waking [9][13].
- Positional devices: Wearable belts with foam bumps or vibrating devices that alert you when you roll onto your back are available, though research on their effectiveness is limited [13].
- Start the night correctly: Even if you do not maintain the position all night, starting in your desired position is a good first step [1].
The bottom line
For most healthy adults, side sleeping offers the best combination of benefits: it supports spinal alignment, keeps the airway open, aids digestion, and may even support brain health [1][6][7]. Back sleeping is a good alternative for people with certain types of back pain, but it should be avoided by those who snore or have sleep apnea. Stomach sleeping is generally the least recommended because of the strain it places on the neck, shoulders, and lower back [8][17].
That said, the best sleep position for you is the one that lets you sleep comfortably and wake up feeling refreshed and free of pain [4]. If you have a medical condition like sleep apnea, GERD, or chronic back pain, talk to a healthcare professional about the position that is safest and most effective for your situation.
Disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice. If you have a health condition that affects your sleep, consult a qualified healthcare provider. We welcome your feedback and corrections. Please contact us if you notice any errors.
References
- [1] How Your Sleep Position Can Impact Heart Health, Metabolism, and More
- [2] Mayo Clinic Minute: What is the best sleeping position?
- [3] Choosing the Best Sleep Position
- [4] Best Sleeping Positions
- [6] The Science of Sleep: A Physical Therapist’s Guide to the Best Sleeping Positions
- [7] Which Side Should You Sleep On?
- [8] Is Sleeping On Your Stomach Bad?
- [9] Does Sleeping on Your Back Cause Sleep Paralysis?
- [10] Healthline Wellness Wire
- [11] Sleeping positions that reduce back pain
- [12] Infant Safe Sleep
- [13] Best Sleeping Position for Sleep Apnea
- [14] FDA warns parents to never use infant sleep positioners
- [15] Best and WORST Sleeping Positions for Your Age & Body Type
- [16] Side Sleeper: Best Positions, Benefits vs. Risks, Tips
- [17] Is Sleeping on Your Stomach Bad for You?
- [18] Situational factors affecting sleep paralysis and associated hallucinations: position and timing effects
- [19] Best position to sleep: Health effects and improvement
