The American was stripped of his seven Tour de France titles and banned for life after a US Anti-Doping Agency report described him as the ringmaster of the "most sophisticated, professionalised and successful doping program that sport has ever seen."
Armstrong ended years of vehement and often vicious denial on Thursday by confessing to US talk show host Oprah Winfrey that he cheated his way to his record seven Tour titles with systematic use of banned, performance-enhancing drugs.
Cooperation with anti-doping authorities could, in theory, make him eligible for a reduced sanction, and in the second part of the interview aired on Friday Armstrong said he was holding out hope he could one day compete in a sanctioned event.
"If you're asking me if I want to compete again, the answer is, 'Hell yeah, I'm a competitor,'" the 41-year-old said.
"It's what I've done all my life. I want to race ... There are lots of things I can't do because of the ban. If there is a window of opportunity would I like to run the Chicago marathon when I'm 50? Yes."
Armstrong acknowledged he deserved to be punished but said the penalty he was given was much harsher than the sanctions dished out to other self-confessed cheats, who were given lesser sentences for testifying against him.
Several former team mates, including Levi Leipheimer and Christian Vande Velde, received six-month bans after cooperating with anti-doping authorities.
"When you see the punishment, you are trading my story for a six-month ban, so I got a death penalty meaning I can't compete," he told Winfrey.
"I'm not saying that is unfair but it is different."
USADA are unlikely to offer any reduced sanction unless Armstrong provides answers to lingering questions such as blood tests USADA says showed he was still doping when he came out of retirement to race in 2009 and 2010.
"Armstrong's blood test results during the 2009 and 2010 Tours de France are consistent with his continued use of blood doping," the USADA report stated.
Armstrong maintains he stopped using banned substances and doping methods after his last Tour title in 2005, and reiterated that point in Friday's broadcast.
Winfrey asked Armstrong if he hoped the lifetime ban would be lifted.
"Selfishly yes," he replied. "But realistically, I don't think that's going to happen, and I've got to live with that."
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