How Sleeping Position May Fight Alzheimer's
The prayer that begins “Now I lay me down to sleep” may acquire a whole new meaning if the findings of a recent study from Stony Brook University School of Medicine can be applied to humans. A research team reported that “the lateral position during sleep has advantage with regard to the removal of waste products including Aβ [amyloid-beta],” the accumulation of which is associated with Alzheimer’s disease.
Previous clinical research has shown that sleep supports the clearance of amyloid-beta from the brain, according to the authors. The system that is involved in the removal of such waste products is called the glymphatic system (aka, glymphatic clearance pathway).
In fact, one of the co-authors of this new study, Maiken Nedergaard, PhD, at the University of Rochester, had previously shown that the glymphatic pathway is more efficient during sleep or under anesthesia when compared with being awake.
The glymphatic system is a functional pathway for waste for the central nervous system. It involves the cerebrospinal fluid, which filters through the brain and interacts with interstitial fluid. This activity removes waste materials, such as proteins (e.g., amyloid-beta and tau) associated with the development of Alzheimer’s disease and other neurological diseases.
Part of the network also includes brain cells called astroglial cells. These cells have endfeet that ensheath the vessels in the brain. According to Helene Benveniste, MD, PhD, the study’s lead investigator and professor in the department of Anesthesiology and Radiology at Stony Brook, the astroglial endfeet have water channels that are necessary for helping the glymphatic system flush waste products out of the brain.
Sleeping position findings
In this newest research, Benveniste’s team used magnetic resonance imaging to view the glymphatic pathway in rodents in three different positions: side (lateral), down (prone), and up (supine). They repeatedly observed that the glymphatic network was most efficient when the rodents were in a lateral position. Why is this so?
The authors explained that when the body is in a prone position, more of the cerebrospinal fluid goes to areas other than to the brain glymphatic pathway, such as toward the spine and the blood vessels in the neck. This results in a reduction in the amount of waste that is flushed out.
Based on their findings, the authors propose “that the most popular sleep posture (lateral) has evolved to optimize waste removal during sleep” and that sleeping position “must be considered in diagnostic imaging procedures developed in the future” when evaluating the transport of cerebrospinal fluid and interstitial fluid in humans.
So could a side sleeping position help fight Alzheimer’s? Benveniste told Bioscience Technology that “any life-long habits that can promote optimal waste removal via the glymphatic pathway might help prevent or postpone onset of neurodegenerative diseases such as Alzheimer’s.”