Short answer: Possibly, yes. Research using brain imaging in animals found that sleeping in the lateral, or side, position appeared to clear metabolic waste from the brain more efficiently than sleeping on the back or stomach. This research hasn’t yet been directly confirmed in humans, but experts consider it a genuinely promising early finding.
What the Research Actually Found
The brain has its own dedicated waste-clearance system, called the glymphatic system, discovered in 2012 and most active during deep sleep. It’s responsible for clearing away metabolic waste products, including amyloid-beta and tau proteins, the same substances that accumulate abnormally in Alzheimer’s disease. Because this system does the bulk of its work while you’re asleep, researchers have become increasingly interested in whether specific sleep habits, including body position, might influence how well it functions.
The key study on this question comes from researchers at Stony Brook University, published in the Journal of Neuroscience. Using dynamic contrast MRI to image the glymphatic pathway in rodents, the research team, led by Dr. Helene Benveniste and Dr. Hedok Lee, compared waste clearance efficiency across three sleeping positions: lateral (side), prone (stomach), and supine (back). The analysis consistently showed that glymphatic transport was most efficient in the lateral position compared to the other two. Dr. Benveniste noted that this pattern held up consistently across the study.
An important caveat is baked directly into the research: this study was conducted in anesthetized rodents, not awake humans. Dr. Benveniste herself was clear that while the findings suggest the human glymphatic system may work similarly, testing in humans using MRI or other imaging methods is a necessary next step before drawing firm conclusions about people. That confirming human research is still limited, so this remains a genuinely promising but not yet fully proven finding when it comes to humans specifically.
It’s also worth keeping sleep position in perspective relative to other factors. According to reporting from The Healthy, sleep experts emphasize that how much and how well you sleep matters considerably more for glymphatic function than which position you happen to sleep in. Getting consistent, sufficient sleep and treating conditions like sleep apnea, which is itself strongly linked to disrupted waste clearance, are considered higher-priority factors. Deep, slow-wave sleep is what most directly supports the glymphatic system, regardless of body position, which is why experts generally frame sleep position as a potential bonus rather than a primary lever for brain health.
What You Can Reasonably Do With This Information
- Consider side sleeping if you’re comfortable with it. Given the current evidence, there’s little downside to favoring the lateral position, even though human confirmation is still pending.
- Prioritize sleep quantity and quality first. Consistently getting 7 to 9 hours of good-quality sleep matters more for glymphatic function than the specific position you sleep in.
- Get evaluated for sleep apnea if you suspect it. Since apnea is strongly linked to impaired waste clearance, treating it is likely to matter far more than adjusting sleep position alone.
- Don’t force an uncomfortable position. If side sleeping causes you pain or disrupts your sleep, the resulting poor sleep quality would likely outweigh any positional benefit.
In short, side sleeping has a genuinely interesting, biologically plausible research basis for supporting brain waste clearance, but it’s still an emerging finding built primarily on animal studies. It’s reasonable to view it as a small potential bonus, not yet a proven human intervention, and one that shouldn’t distract from the more firmly established basics of getting enough good-quality sleep.
