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Sleeping on your side to prevent Alzheimer’s? Rat study conclusions applied too broadly to humans

Could Body Posture During Sleep Affect How Your Brain Clears Waste?

Our Review Summary

BrainClearsWasteLateralPosition 410x123

The illustration that accompanied this news release on a study involving rodents.

This news release from Stony Brook University in New York describes a preliminary research finding that suggests sleeping on your side rather than in a prone (lying flat, face downward) or supine (lying face upward) position aids the elimination of metabolic waste products that build up in the brain while asleep. It’s definitely an interesting finding that supports research published in 2013 from the University of Rochester. The problem with both of these studies is that, to date, none of these findings have been replicated in humans. In reality, only about one-third of findings in animals translate to successful interventions in people. The release hints at this issue by stating that the researchers’ hunch on sleeping posture and waste-clearing efficiency is just that — speculation — and that human studies are required to know for certain. But the release should have alerted readers that the study involved anesthetized rodents, and not sleeping humans, earlier in the text.


Why This Matters

Science has made it increasingly clear that sleep plays important roles in overall health — not just our mood and alertness. And this release suggests that certain sleep positions may help “flush out” potentially harmful proteins like tao and amyloid which are found in greater quantities in the brains of people with Alzheimer’s. That intriguing finding could, one day, prove relevant to efforts to prevent this dreaded disease in humans. But it’s far too soon for anyone to consider adjusting their own sleep practices based on these findings.


Does the news release adequately discuss the costs of the intervention?

Not Applicable

Cost is not an applicable criteria since there’s no cost associated with sleeping (unless one goes to a sleep clinic).

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

We identified two important problems with the way benefits are described:

  • The news release takes a huge leap when it states that sleeping on one’s side “may effectively remove brain waste and prove to be an important practice to help reduce the chances of developing Alzheimer’s, Parkinson’s and other neurological disorders.” It could, then again it may not. The study hasn’t been replicated in humans, and even if it had been, it’s not clear that better removal of “brain waste” would help prevent these types of diseases.
  • The release does not quantify the efficiency of brain waste removal in any way (i.e. of fluorescent and radioactive tracers used in rodents). The difference between prone and other positions could be minuscule or major — readers can’t be certain without such a clarification.

Does the news release adequately explain/quantify the harms of the intervention?

Not Applicable

The harm of changing one’s sleeping pattern is not addressed. While there are people with certain health conditions that can’t sleep on their side, it doesn’t seem like an applicable criteria for rating this release.

Does the news release seem to grasp the quality of the evidence?

Not Satisfactory

The news release adequately explains how they came to observe the glymphatic pathway in rodents using dynamic contrast magnetic resonance imaging (MRI). However, the notification that the study involved rodents comes a bit far down in the release for our liking — well after the release has suggested the findings could have important implications for Alzheimer’s disease prevention in humans. In addition, the release doesn’t describe any of the study parameters such as the size of the rodent sample, the key measurements, or study length.

There is one silver lining, in terms of quality of evidence, and it’s this line at the end of the release: “Dr.Benveniste cautioned that while the research team speculates that the human glymphatic pathway will clear brain waste most efficiency when sleeping in the lateral position as compared to other positions, testing with MRI or other imaging methods in humans are a necessary first step.” Although that’s a welcome caveat, we think it comes too late in a release describing such a very preliminary study.

Does the news release commit disease-mongering?


We saw no evidence of disease mongering. The release is careful to talk about efficiency in clearing brain waste and doesn’t suggest that a non-prone position could be harmful.

Does the news release identify funding sources & disclose conflicts of interest?

Not Satisfactory

The release does not tell us who funded the study. According to the study, the work was supported by “FBRI” (not clear what that stands for), the National Institutes of Health, and the Department of Anesthesiology at Stony Brook Medicine.

Does the news release compare the new approach with existing alternatives?

Not Satisfactory

The release compared the potential benefit of sleeping on one’s side and on the stomach or back. But there are many other potentially modifiable risk factors for Alzheimer’s and other neurodegenerative diseases that weren’t mentioned. Things like exercise, a healthy diet. maintaining social connections, etc have been more thoroughly studied than sleep positions.

Does the news release establish the availability of the treatment/test/product/procedure?

Not Applicable

Because everyone sleeps this criteria doesn’t apply for this particular release.

Does the news release establish the true novelty of the approach?


The release states that SBU researchers discovered that lateral sleeping is the best method for removing waste from the brain. The researchers are apparently building on the research of University of Rochester scientists who discovered and named the glymphatic system, a network that drains waste from the brain, in 2013.

Does the news release include unjustifiable, sensational language, including in the quotes of researchers?

Not Satisfactory

The Not Satisfactory rating here applies to the accompanying artwork as much as it does the text — the illustration depicts a human, but we think it would have been more appropriate to show a sleeping rodent. The release also makes statements that clearly refer to humans or refer to rodents and humans as interchangeable, and we don’t think the disclosure near the bottom that “testing with MRI or other imaging methods in humans are a necessary first step” is enough to counterbalance this.

Total Score: 2 of 7 Satisfactory


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