Do you know which position do you sleep in? We spend one third of our day sleeping in bed. I tend to sleep on my back (Starfish!) more than on my side or stomach. There is a recent research which shows that a right sleeping position can help us avoid neurological decline. Research was conducted by researchers at Stony brook University and they found that sleeping in lateral position help to remove brain wastes faster than sleeping in other positions does.

What do our brain do when we are sleeping?

Sleeping position can help removing wastes that can ‘clog’ our brain. The removal of brain waste depends on our glymphatic system. According to previous researches, just like our lymphatic system which transport wastes out of our organs, our glymphatic system is the disposal system for our brain. It works most effectively when we are sleeping. The build up of brain waste can affect our neurologic system negatively increasing the possibility of getting neurological diseases like Alzheimer’s. According to theguardian, blood vessels carrying cerebrospinal fluid pick up wastes by exchanging with the interstitial fluid in our brain in the process of entering the intercellular space in our brain tissue.

Research on mice 

The researchers conducted an observational study by measuring the exchange rate of cerebrospinal fluid and interstitial fluid in mice’s brain when they are put to sleep on their side (lateral), back (supine), and stomach (prone). The figure below is from the research paper which shows the “retention” and “loss” of a chemical (Gd-DTPA) injected to the mice’s brain. The higher the rate of retention, the slower the exchange rate cerebrospinal fluid and interstitial fluid, meaning slower the waste cleaning process. It shows a difference in the brain’s efficiency of clearing waste in different sleeping position.

This study has rejected the null hypothesis and therefore it is either correct or a false positive. When I searched about this topic online, I only found this research paper which means that more researches should definitely be done. A meta-analysis should be used to minimize the chance of the result being a fluke. Although the mechanism seems to be clear in this research, we still cannot eliminate chance. Also, since this is not a controlled trial, we can never fully eliminate the presence of confounding variables and reverse causation. A confounding variable can be the use of a anesthetic. It can influence the sleeping pattern of the mice and lead to different result from normal sleeping, as the study mentioned.

Since this study is only conducted on rodents, there are a lot more possibility and difference in human. The study also mentioned that researchers can not yet measure the effect of change in sleeping positions on the brain. This study reminds me of Dr. Spock’s study of babies’ sleeping position which killed thousands of babies. This also tells us our sleeping position can have a huge impact on our body. I am wondering what would be the difference if our body is in supine position but head is turned to the side because this is the position I am always in. However, I believe after looking at the study, we should all try to sleep on our side.

Work Cited:

Lee, H., L. Xie, M. Yu, H. Kang, T. Feng, R. Deane, J. Logan, M. Nedergaard, and H. Benveniste. “The Effect of Body Posture on Brain Glymphatic Transport.” Journal of Neuroscience 35.31 (2015): 11034-1044. Web.

Costandi, Mo. “How to Optimise Your Brain’s Waste Disposal System.” The Guardian, 22 Aug. 2015. Web. 15 Oct. 2015.

“Could Body Posture During Sleep Affect How Your Brain Clears Waste?”Could Body Posture During Sleep Affect How Your Brain Clears Waste?Stony Brook University, 4 Aug. 2015. Web. 15 Oct. 2015.