The human brain flushes out waste products while we sleep and now it seems that certain sounds might enhance the process https://www.newscientist.com/article/2588451-bursts-of-pink-noise-during-sleep-seem-to-help-flush-waste-from-brain/?utm_term=Autofeed&utm_campaign=echobox&utm_medium=social&utm_source=Twitter#Echobox=1788977340