In 2012-2013, preliminary research demonstrated the existence of a specific brain-cleaning system that is most active during sleep. New studies have tried to determine the ideal body posture for promoting this brain waste disposal system. On your back, stomach, side… what position is best for cleaning out your brain? Does brain health depend on the position we choose to sleep in? Let’s first take a look at what happens in rats!

Back to the cleaning system… Research begun in 2012 by a team of scientists at the University of Rochester uncovered the existence of a glymphatic system, which is responsible for brain clearance. The waste produced by neurons is evacuated into the cerebrospinal fluid, and is eliminated through the venous system. This waste treatment is crucial to brain function. If it’s not efficient, waste accumulates. And it appears that this glymphatic system is more active during sleep.

Today, the results of these studies (published in the Journal of Neuroscience) indicate that body posture during sleep may affect cleaning efficacy, at least in rats. The experiment took place as follows: three groups of rats were anesthetized and forced to sleep on their backs, sides, or stomachs. Their brains were examined using MRI, particularly in four specific areas: the hippocampus (memorization), the cerebellum (control of movement), the midbrain (vision and hearing), and the orbitofrontal cortex (decision-making). The results were clear: in these areas, cleaning was most effective in the animals that slept on their side.

Caution should be taken before generalizing these results to humans. As Helene Benveniste from Stony Brook University, one of the study’s co-authors points out, anesthetized rat brains aren’t quite the same as sleeping rat brains. And the fact that we change position during the night can also affect clearance of brain waste. According to Benvesite, these are important questions to consider.