In his monthly 'Mann ki Baat' radio broadcast, he said he was overwhelmed by the response to his 'fit India' campaign.
"For me, it's heartwarming that the captain of the Indian cricket team Virat Kohli has included me in his challenge... I too have accepted his challenge. I believe this is gainful and this kind of a challenge will inspire us to be fit alongwith others, as well," he said.
But at the same time he expressed concern over "fading away" of traditional sport such as 'kho khho', 'pitthu', 'lattu' and 'gulli-danda' "to the point of extinction".
"...it will be the loss of the spirit of childhood," he said and recalled a poem which talked of end of childhood and the games and the fun associated with it.
"It is crucial that today schools, neighbourhoods and youth congregations come forward and promote these games. Through crowd sourcing we can create a very large archive of our traditional games," Modi suggested.
He said the videos of these games can be shot, outlining the way to play them along with the mandatory rules and regulations.
Animation films, he suggested, can also be made so that the young generations can see and play for themselves.
On the 'Fit India' campaign, the prime minister said, "The more we play, the more we inspire the country to come out and play."
He said people are sharing videos of 'fitness challenge' on social media and everybody is getting connected with the Fit India campaign.
"People from the film fraternity, from the world of sports, common citizens of the country, members of the armed forces, school teachers or even those toiling in fields are building up a crescendo Hum Fit toh India Fit' If we are fit, India is fit'," he said.
He said games are not just games; they teach us values for life, such as, setting targets, building up determination, developing team spirit and fostering mutual co-operation.
"And then, there is no prescribed age limit for participating in them. From tiny tots to grandfather-Grandmother, when we all play these games together then the term generation gap' disappears," he said.
The prime minister also highlighted the need to have a sense of adventure, saying adventure gives birth to development.
He referred to the all women team of Indian navy which circumnavigated the globe for more than 250 days on board the INSV Tarini.
He also complemented people, some women and a girl, who climbed the Mount Everest. He also appreciated a BSF team who cleaned up Mount Everest of garbage while returning.
PM Modi also had a word of praise for Cuttack's D Prakash Rao, a tea seller, who spends 50 per cent of his earnings to run a school.