Journalist Peter Seewald recalled in an article for German weekly Focus published Saturday asking Benedict during a meeting last August at the pontiff's summer residence, Castel Gandolfo, what more could be expected of him and his papacy.
Seewald said Benedict replied: "From me? From me, not much more. I am an old man and my strength is running out. And I think what I have done is enough."
Asked whether he was considering resignation, Seewald said that Benedict responded: "That depends to what extent my physical strength will compel me to."
Benedict has announced that he would resign Feb. 28, making him the first pope to step down in nearly 600 years.
The announcement stunned the world, but the pope had laid the groundwork for a possible resignation when Seewald interviewed him for his 2010 book, "Light of the World."
"If a pope clearly realizes that he is no longer physically, psychologically and spiritually capable of handling the duties of his office, then he has a right, and under some circumstances, also an obligation to resign," the book quoted Benedict as saying.
He stressed, however, that resignation was not an option to escape a particular burden, such as the scandal over sexual abuse by clerics.
In Saturday's article, Seewald recalled asking the pope in August how badly the scandal over leaks of papal documents, in which the pope's ex-butler was convicted of aggravated theft, had affected him.
It "is not as though I were somehow falling into a kind of desperation or world-weariness — it is simply incomprehensible to me," Benedict said, according to Seewald.
Benedict said the affair had not thrown him off his stride or made him tired of his office, "because I think this can always happen," Seewald added.