The life cycle of an athlete is usually shorter than that of any other person in any other type of work. However, there are some exceptions: Cristiano Ronaldo, LeBron James, and Tom Brady are three of the world's most-renowned athletes that continue to perform at an age where most of their colleagues are already retired.

12 years after he left Old Trafford to join Real Madrid, the Portuguese megastar made a shocking return to Manchester United last summer and made it look like he never felt.  It's been more than a decade, but the Red Devils have seen the same Ronaldo this season - only that he's 36 years old now. 

But for him, age seems to be just a number. His inspiring work ethic has helped him make the best of his unparalleled talent to continue playing until now and it doesn't seem that he wants to stop anytime soon.

Man United star Cristiano Ronaldo wants to continue playing until he's 42

In an interview with ESPN Brasil, Ronaldo has addressed his longevity and opened up on retirement plans. "Genetically I feel like I'm 30 years old. I take great care of my body and my mind. Something I've learned recently is that after 33, I believe the body can deliver if you need it, but the real battle is mental.

"Going through many things with the focus on the end goal of staying at a high level is the hardest thing, and that's what I've been doing for the last few years," he continued. "I've been working and focusing more on working on my mind. I know my body will handle me because I have a lot of respect for it and I listen to it a lot. I want to find out if I'm going to play until I'm 40, 41, or 42, but the most important thing is that my daily goal is to enjoy the moment."

Cristiano Ronaldo on longevity and LeBron James, Tom Brady's cases

Cristiano Ronaldo has also been asked about other veteran superstars in other sports like LeBron in the NBA and Tom Brady in the NFL. He didn't elaborate on it but suggested some differences between each case.

"I think a very important point is the difference between sports," Ronaldo said. "You mentioned some excellent athletes who have already been active for many years. In my opinion, there is no other sport that has as much workload as soccer. The NBA, for example, has long rest periods, but I don't want to expand on that."