Sleeping on your side appears to cut the risk of neurological disorders
New research suggests that sleeping on your sidecould help cut the chances of developing some neurological disorders, includingAlzheimer's and Parkinson's. Compared to sleeping on one's back or stomach,sleeping on one's side appears to allow the brain to more efficiently removewaste chemicals that may contribute to the development of such conditions.
Theresearch team, led by Helene Benveniste, MD, PHD, a Professor in the Departments of Anesthesiology and Radiology at Stony Brook University School of Medicine, used dynamic contrastmagnetic resonance imaging (MRI) to view the glymphatic pathway in rodentbrains. This is the system in mammals responsible for clearing wastes and otherharmful chemical solutes from the brain by way of cerebrospinal fluid (CSF)filtering through the brain and exchanging with interstitial fluid (ISF).
Itis during sleep that the glymphatic pathway is most efficient at removing brainwaste, including amyloid β and tau proteins, whose build up in the brainis associated with Alzheimer's and Parkinson's. The researchers ascertained theefficiency of this system in the brains of anesthetized rodents in the side,down and up sleeping positions by viewing the CSF-ISF exchange rates via MRI.
"The analysis showed us consistently thatglymphatic transport was most efficient in the lateral (side) position whencompared to the supine (up) or prone (down) positions," said Dr.Benveniste. "Because of this finding, we propose that the body posture andsleep quality should be considered when standardizing future diagnostic imagingprocedures to assess CSF-ISF transport in humans and therefore the assessmentof the clearance of damaging brain proteins that may contribute to or causebrain diseases."
Colleagues at the University of Rochester validatedthe MRI data and assessed the influence of body posture in clearing amyloidfrom the brains using fluorescence microscopy and radioactive tracers.
"It is interesting that the lateral sleepposition is already the most popular in human and most animals – even in thewild – and it appears that we have adapted the lateral sleep position to mostefficiently clear our brain of the metabolic waste products that built up whilewe are awake," says Dr. Nedergaard, PHD, from the University of Rochester."The study therefore adds further support to the concept that sleepsubserves a distinct biological function of sleep and that is to 'clean up' themess that accumulates while we are awake. Our finding brings new insight into this topic by showingit is also important what position you sleep in."
Although the researchers expect the human glymphaticpathway will also clear brain waste most efficiently when a person sleeps ontheir side, tests on humans are still required to confirm this.
The team's paper appears in the Journal ofNeuroscience.
Source: Stony Brook University