Recent research demonstrates a good reason to sleep deeply: the slow and steady brain (and cardiopulmonary) activity associated with deep non-REM sleep are best for the function of the glymphatic system, the brain’s unique process of removing waste. That waste includes toxic proteins like beta amyloid and tau which are associated with Alzheimer’s.
Here are two media articles on the work:
Not all sleep is equal when it comes to cleaning the brain
Study: Deep Sleep Best for Brain ‘Cleaning,’ Emphasizes Link Between Sleep and Alzheimer’s
The research article is published at [paywall]: Science 22 Feb 2019: Vol. 363, Issue 6429, pp. 831-832.
The links have been added to Alzheimer’s > Neurology & Neuroplasticity.