Footer 1

Nav Bar

Become a subscriber today to get unlimited access

Member-exclusive 

You've run out of free articles. Read unlimited, ad-free stories (including this one) by becoming a Member. 

Join to continue reading

BACK TO SCHOOL SALE
Save 25% on a year of Nautilus— for everyone who never stopped learning.&nbsp;&nbsp; Our lowest price of the season.

drainage

Sleep: When Brain Cells Shrink & Neuro Trash Is Flushed Away