I havn’t been keeping references, but this isn’t the first paper I’ve seen suggesting part of REM cycle is used to flush fluid build up in parts of the brain, a

I havn’t been keeping references, but this isn’t the first paper I’ve seen suggesting part of REM cycle is used to flush fluid build up in parts of the brain, and that this flushing is necessary for high cognitive utilization. Also, this flushing seems to be difficult or impossible without REM (though I suspect vigorous exercise helps). I wouldn’t be surprised if lack of sleep could help contribute to Alzheimer symptoms, if not the actual disease side effects of brain structure deterioration.