Sleeping only six hours a night for a week in a row will make you feel on that eighth day as if you'd gotten no sleep at all. Seven and a half to eight hours remains the sweet spot.
I think tension between the intimate and the vast is at the heart of every poem by any poet, though of course the terms with which it is explored vary. Perhaps it is something we seek out in order to affirm that our small lives are tethered to something large and ongoing.