I'll leave a more rigorous answer to your question to a doctor, but there is evidence that Alzheimers disease is caused by a buildup of "plaques" (beta-amyloid,

I'll leave a more rigorous answer to your question to a doctor, but there is evidence that Alzheimers disease is caused by a buildup of "plaques" (beta-amyloid, a toxic protein) in the brain tissue. This buildup is removed during R.E.M sleep in those without the disease. https://www.nih.gov/news-events/nih-research-matters/how-sleep-clears-brain https://www.nih.gov/news-events/nih-research-matters/how-sle... I've heard claims about sleep triggering a general "cleansing" of the brain, but I'm not a neurologist, so I can't say for certain there's evidence for the general case.