Since you mention Nietzsche, he had the following to say on precisely this topic in "Ecce Homo":
"In my case all reading is among my recreations: consequently among those things which free me from myself, which allow me to saunter among strange sciences and souls – which I no longer take seriously. It is precisely reading which helps me to recover from my seriousness. At times when I am deeply sunk in work you will see no books around me: I would guard against letting anyone speak or even think in my vicinity. And that is what reading would mean … Has it really been noticed that in that state of profound tension... (read more)
Since you mention Nietzsche, he had the following to say on precisely this topic in "Ecce Homo":
"In my case all reading is among my recreations: consequently among those things which free me from myself, which allow me to saunter among strange sciences and souls – which I no longer take seriously. It is precisely reading which helps me to recover from my seriousness. At times when I am deeply sunk in work you will see no books around me: I would guard against letting anyone speak or even think in my vicinity. And that is what reading would mean … Has it really been noticed that in that state of profound tension... (read more)