During the course of the night, our body is busy restoring, repairing, and replenishing its many systems. As we sleep, cell, organ, and muscle repair is well underway, immunity is boosted, and our brain is ridding itself of waste (via WebMD). Most of this work takes place during the deepest stages of sleep, and while younger people spend about 20% of the night in deep sleep, this percentage rapidly decreases as we age, sometimes dropping to 0% by age 65. Because this clearing of brain waste is essential, adequate sleep is critical in reducing the risk of Alzheimer’s disease in older adults, per Express.
The forgetfulness, disorientation, mood changes, and progressive memory loss symptoms that characterize Alzheimer’s disease are the result of protein buildup within the brain. Often beginning along the sides of the brain, this progressive buildup surrounds the brain cells and interferes with the neural messaging of information within the brain, according to Express.
As of 2024, roughly 6.2 million Americans over the age of 65 are reportedly diagnosed with Alzheimer’s dementia — a number that is projected to increase to nearly 14 million by 2060 (via Alzheimer’s and Dementia). As it turns out, however, sleeping on your side at night may help in the prevention of the disease.
Side-sleepers may be at a lower risk for Alzheimer’s
In a 2024 study published in the Journal of Neuroscience, researchers conducted animal studies on mice to examine the relationship between sleep position and function of the glymphatic pathway — the waste-clearing center of the brain. Using MRI technology, researchers concluded that the “lateral sleeping position” proved most effective at clearing waste chemicals from the brain, including those responsible for the onset of Alzheimer’s.
This news bodes well for the 74% of the population who are already preferred side-sleepers (via Casper). Principal investigator of the study and a professor in the Departments of Anesthesiology and Radiology at Stony Brook University School of Medicine Dr. Helene Benveniste explains that side sleeping consistently won out against back or stomach sleeping, writing in the scientific paper, “The analysis showed that glymphatic transport was most efficient in the lateral position compared with the supine or prone positions.”
While research on human subjects is still needed, fellow researcher on the study Dr. Maiken Nedergaard shares how these findings have the potential to influence means of managing symptoms related to Alzheimer’s and other brain diseases, stating, “Many types of dementia are linked to sleep disturbances, including difficulties in falling asleep. It is increasing[ly] acknowledged that these sleep disturbances may accelerate memory loss in Alzheimer’s disease. Our [finding] brings new insight into this topic by showing it is also important what position you sleep in” (per Science Daily).
