A lot happens under the cover of night; offices are cleaned, roads are maintained, and the power grid rests. It is all quite nicely analogous to what happen in your brain; rest, maintenance and cleaning. Now a new study has shown that the cleaning part of this equation in your brain is altered according to what position you sleep in.
During the day the metabolic activity in your brain generates waste that needs to be removed and a lot of that removal happens at night via system known as the glymphatic pathway. Essentially, the glymphatic pathway involves cerebrospinal fluid filtering through the brain and exchanging with interstitial fluid (the fluid between brain cells) to clear waste in much the same way as lymphatic fluid clears waste from body tissues. During sleep is when the glymphatic pathway is most efficient and it removes waste such as beta-amyloid and tau proteins which impair brain function if they build up.
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In this study researchers wanted to see whether sleeping position impacts the efficiency of the glymphatic system. So they anaesthetised rats and had them lie in one of three positions; lateral (on the side), prone (on the stomach), and supine (on the back).
The researchers used MRI to image the glymphatic pathway and found that it is most efficient when the rats lay on their side. This was reinforced by using tracing data that showed that lyng on the side increased the removal of amyloid from the brain.
Since sleeping on the side is the naturally most popular position for sleeping in both humans and animals, the researchers think that may be because this is the position that allows for the most efficient clearance of waste from the brain.
Many types of dementia are linked to sleep disturbances and it seems now that sleep position may be part of that. At least it reinforces that whatever you may be up to during the day, you really do need to get some sleep on the side.
