I read this article recently:
http://articles.mercola.com/sites/articles/archive/2014/04/03/sleep-loss-alzheimers-disease.aspx
The big take-away for me was this:
Previous research, published in the journal Science,8 has also revealed your brain removes toxic waste during sleep through what has been dubbed "the glymphatic system."9, 10, 11, 12, 13 This system ramps up its activity during sleep,…