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Want to rid your brain of toxic build-up and perhaps stave off Alzheimer’s Disease? Don’t sleep sitting up.

by Carolyn Lacey , 24 Aug 2015.

Planning on taking a power nap at your desk today? You might want to think twice about your sleeping position. The research article I’m about to summarize makes me think of all those times I have actually managed to get some sleep on a long-haul flight… only to wake up still feeling terrible (even after drinking litres of water) and all the elderly people I know who often like to take cat-naps sitting in their favorite armchairs.


Here’s the problem with sleeping in an upright position like sitting: your brain may not properly clean up all of the toxic waste it builds up from working hard.

Sleeping upright


The study published in The Journal of Neuroscience from New York labs (Helene Benveniste; Stony Brook University and Maiken Nedergaard; University of Rochester) looked at different sleeping positions in rodents and examined the efficiency of brain self-cleansing and clearance of toxic waste like the kind linked with neurological diseases like Alzheimer’s Disease.


Active brain cells generate toxic waste by-products. These include proteins such as Amyloid-β; the main peptide found in the plaques that develop in brains of people with Alzheimer’s Disease. These plaques are thought to result in neuronal damage. Sleep is important for clearing this waste. It has been found in previous studies that the amount of amyloid-β content in the fluid that bathes the brain (cerebrospinal fluid) is decreased in sleep when compared to awake and, also, amyloid-β build-up increases with chronic sleep deprivation (see link to Science paper below).


The New York study took rodents and put them in a brain scanning machine (MRI machine) while they were “sleeping” (using anesthetic). They positioned the rats in a variety of sleeping positions and measured, with tracers, how well the cleansing system between brain cells (called the glymphatic system, see more below) cleared toxic waste.


They found that not all sleeping positions are created equal when it comes to brain cleansing. The brain is far more effective at clearing up the toxic waste when the rats were sleeping on their side rather than back sleeping (supine) or front sleeping with head elevated (prone; also more like awake position for rodents or like sleeping with your head on the desk). The worst of all three sleeping positions for the brain ability to clear toxic waste was sleeping on the front.


The authors suggest that front and/or head upright position might reduce the brain’s capability of cleansing itself due to possible more pressure on neck nerves and blood vessels, and also position of the heart.


Since reading this article, I have certainly thought twice about what position I fall asleep in, and it also has made me wonder about elderly people, with risk of Alzheimer’s, and falling asleep in their armchairs… Of course all this still has to be tested in humans but, in case this turns out to be true also in humans, take your power naps curling up on the floor under your desk rather than with your head on your desk.


Further reading:


To view the original paper discussed in this blog “The Effect of Body Posture on Brain Glymphatic Transport” in Journal of Neuroscience please click here.

The Blog was written by Carolyn Lacey, Scientific Outreach Manager at Neurexpert. To learn more about Carolyn and Neurexpert, please click here.