During his visit with Winfrey that appeared on her television network over two nights, Armstrong admitted to using performance enhancing drugs during his record run of seven consecutive Tour de France titles beginning in 1999.
In the second portion of the interview shown Friday, Armstrong said he thought the punishment he received from the International Cycling Union was too severe.
He has been banned from virtually all types of competitions, some of which he said he might like to attempt as he grows older.
"Not the Tour de France," he said, "but there's a lot of other things that I could do but I can't.
"With this penalty and with this punishment, which again I made my bed. But would I like to run the Chicago Marathon when I'm 50? I would love to do that. And I can't. I can't lie to you, I'd love the opportunity to be able to compete.
"I deserve to be punished. I'm not sure that I deserve a death penalty."
Armstrong said the worst thing about his fall from grace was when he was advised to leave his position as chairman of his Livestrong foundation -- a cancer awareness charity.
"The foundation is like my sixth child," he said. "And to make that decision and to step aside was -- that was big. That was the lowest."
Armstrong has been stripped of his Tour de France victories and has been handed a lifetime ban by the governing body of cycling.