Tennis players generally have longer careers these days with many playing well into their 30s. The 36-year-old Nadal and 35-year-old Djokovic are still the best in the business despite being on the wrong side of 30 while Federer retired at the age of 41 in September.
22-time Grand Slam champion Nadal, who turned professional in 2001, feels the advancement of medicine and professionalism are important, but also acknowledged the part that the rivalry between the Big Three has played in prolonging their careers.
Asked about his lengthy career and how he will remain on top of his game health and fitness wise, he replied: "What may happen in the future I don't know, I don't know the consequences that may happen, time will tell.
"There are several factors why we are playing longer at an advanced age. One is medicine and the professionalisation of the entire sport which means that people have a more extensive team, and there is more knowledge of the things that help to lengthen careers.
"And there is another thing: I think Roger, Novak and I have been pushing each other, and somehow it's never been enough, we've always had to make another effort.
"The competition [between us] has taken us to extreme mental and tennis levels, and this is one of the main reasons why we have continued for so long."
Nadal, who is currently on an exhibition tour of Latin America with Casper Ruud, became a first-time father in October as his wife Mary Perello gave birth to a baby boy and he appreciates that tennis has to take a backseat to family, but he will continue to be professional when it comes to his tennis career.
"Having a son is something very recent, it is something in life which you have to adapt to," the former world No 1 said.
"Beyond that, I'm happy, I'm enjoying the moment and everything else takes a backseat. But my intention is to continue doing my best to fight for the things that excite and motivate me, after that you have to be well-organised and have everything well set up to be able to develop your professional life in a way that works."