Sleep On It To Prevent Alzheimer’s?
And now for something completely different: New research from investigators at Stony Brook University, New York, concludes that your sleep position may affect your risk of developing Alzheimer’s disease and other brain-related conditions. That’s right, side sleepers. You may be at a distinct advantage when it comes to clearing “brain waste” at night, compared to back or stomach sleepers. Who knew?
Most people have a preferred sleep position. In fact, among humans and many other animals, the lateral—or side sleep—position is the most common way to sleep. But not everyone prefers to sleep on their side. Some can’t get fully comfortable unless they’re sleeping on their backs. Others prefer the stomach position. Sleeping on one’s back may help improve mucus drainage among people suffering from nasal allergies, but evidently it’s not ideal for allowing the body to remove cellular debris and other forms of waste material from the brain at night. Over time, say researchers at Stony Brook, that might affect one’s long-term risk of developing disorders such as Alzheimer’s, Parkinson’s, or other neurological conditions.
The issue is the “glymphatic pathway;” the mechanism by which cerebrospinal fluid (CSF) filters through the brain and exchanges with interstitial fluid (ISF) to clear waste. The system works much like the body's lymphatic system, which clears waste from other organs. Some of the wastes in question may include substances, such as amyloid β (amyloid) and tau proteins. Although the disease process underlying Alzheimer’s disease remains somewhat unclear, these compounds are know to affect proper brain function if they’re allowed to build up. They’re both present in abnormally large amounts in the brains of Alzheimer’s patients, for instance.
"It is interesting that the lateral sleep position is already the most popular in human and most animals -- even in the wild -- and it appears that we have adapted the lateral sleep position to most efficiently clear our brain of the metabolic waste products that built up while we are awake," says Maiken Nedergaard, PhD, one of the study’s authors, in a press release. "The study therefore adds further support to the concept that sleep subserves a distinct biological function of sleep and that is to 'clean up' the mess that accumulates while we are awake. Many types of dementia are linked to sleep disturbances, including difficulties in falling asleep. It is increasing 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," she said.
Are you a side sleeper? If not, will this information change your approach to sleep? I’d love to hear your feedback.
Hedok Lee, Lulu Xie, Mei Yu, Hongyi Kang, Tian Feng, Rashid Deane, Jean Logan, Maiken Nedergaard, and Helene Benveniste. The Effect of Body Posture on Brain Glymphatic Transport. Journal of Neuroscience, July 2015 DOI: 10.1523/JNEUROSCI.1625-15.2015