Most of us pick a sleep position by feel and never think about it again. A 2025 news article from the American Heart Association makes the case that this small habit is worth a second look, especially if you snore, wake up unrefreshed or live with back pain.
The clearest link between how you lie down and your cardiovascular health runs through sleep apnea. In obstructive sleep apnea, the airway repeatedly collapses during sleep, and the AHA notes this is associated with irregular heartbeats, high blood pressure and stroke risk in its 2021 scientific statement on obstructive sleep apnea and cardiovascular disease.
Why back sleeping can make apnea worse
Sleeping flat on your back, called the supine position, tends to make obstructive sleep apnea more severe. When you lie face up, gravity pulls the tongue and soft tissues of the upper airway backward, narrowing the passage. American Family Physician describes positional therapies as approaches that aim to keep patients off their back and encourage side sleeping, and notes they are considered when patients have a documented lower apnea-hypopnea index in nonsupine positions, according to a review of positional therapy for OSA.
Some patients have what is sometimes called positional OSA, where apnea is much worse on the back than on the side. For those patients, the AHA piece notes, moving off the back is a low-cost lever worth discussing with a clinician, alongside standard treatments like CPAP.
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Stomach sleeping and your lower back
If you sleep face down, your back may be paying for it. A 2025 systematic review in Musculoskeletal Care by Saini and colleagues pooled six observational studies and concluded that the prone position increases low back pain risk through lumbar strain, while supine and well-supported side-lying tend to align with lower pain, according to the review published on Wiley Online Library.
The review is small and based on observational data, so it points to a pattern rather than proving cause and effect. Still, the practical takeaway is straightforward. If you wake with a stiff, aching lower back and you sleep on your stomach, a switch to side sleeping with a pillow between the knees, or to your back with a small pillow under the knees, is a reasonable experiment.
Left side, right side and the fetal curl
Side sleeping is the position most often recommended, and the choice of side can matter for specific conditions. People with heartburn often feel better on the left side, which appears to reduce acid reflux from the stomach. In heart failure, the picture flips. Many patients find left-side sleeping worsens shortness of breath and prefer the right side.
For pregnant women, left-side sleeping is generally advised to support blood flow. And for most other adults, the curled fetal position on the side remains the broadly recommended default, in line with guidance from the Sleep Foundation on evidence-based sleep posture.
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What to try tonight
Sleep position is one of the few health variables you can change in five seconds. If you snore, wake gasping, feel groggy in the morning or struggle with persistent low back pain, trying a few nights on your side is a low-risk first step. A body pillow at the back can make it easier to stay there.
If symptoms continue, or if you already carry a diagnosis of sleep apnea, heart failure or reflux, bring it up with your doctor. Position is a small tool, not a substitute for evaluation and treatment.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.