The Matt Walker Podcast

The Matt Walker Podcast is all about sleep, the brain, and the body. Matt is a Professor of Neuroscience at the University of California, Berkeley. He is the author of the book, Why We Sleep and has given a few TED talks. Matt is an awkward British nerd who adores science and the communication of science to the public.

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The Matt Walker Podcast

#128 - Sleep Position

March 16, 2026 • Dr. Matt Walker

0:00 | 21:32

Matt reviews Danish neuroscientist Maiken Nedergaard's 2013 discovery: during sleep, glial cells shrink, allowing cerebrospinal fluid to flush brain toxins like beta-amyloid and tau protein. This "private sanitation system" is significantly more efficient with side sleeping, especially compared to front or back sleeping, suggesting an evolutionary preference.

Our host reveals the broad impact that sleep position has on health, from reducing sleep apnea and acid reflux to affecting rotator cuff injuries, glaucoma, and stillbirth risk in pregnant women. Overall, he concludes that side sleeping is generally optimal, with specific considerations for heart conditions.

Please note that Matt is not a medical doctor, and none of the content in this podcast should be considered medical advice in any way, shape, or form, nor prescriptive in any way.

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As always, if you have thoughts or feedback you’d like to share, please reach out:

Matt: Instagram @drmattwalker, X @sleepdiplomat,

YouTube https://www.youtube.com/@sleepdiplomat