He is up by 4am every day, walks for two hours on the sprawling grounds of his Gurusaday Road home, and leaves for work by 9am. Five days of the week he is in office from 9.30am to 4pm, helming a not-so-small family business.

B.K. Birla followed this schedule on January 12 as well, which happened to be his 90th birthday.

“My belief in god and a disciplined life keep me going,” B.K. Birla told Metro on his birthday. “After I’m back home, I meet relatives or friends and watch some TV,” adds the big daddy of big business in Calcutta.

For BK-babu, and many more like him, age is just a number. And being 90 years young is a way of life.

Joseph Chiramal does one better. The doorbell rings faintly in his two-bedroom house near the Park Circus connector. The other family members have missed the bell, but Chiramal’s ears are sharp enough to catch it. He shuts the Biblical book he is reading and shuffles to the door.

Chiramal turns 101 on January 25.

“At 88, he would go to the Park Circus market and do the daily bazaar. At 98, he was still walking to Sunday church on his own. And now at 100, he makes it to the community hall to count the church collections on Monday mornings,” says his 69-year-old daughter Grace.

Chiramal is still living it up. “I enjoy a good game of bridge… If you’re young at heart, you’re young in body,” he says with a toothless smile.

Not far from the 100-year-old’s home lives 94-year-old Tolaram Agarwal. The resident of Gorachand Road, off Park Circus, begins his day at 5am with yoga. After breakfast (milk and apple), he reads the newspaper and a few religious publications. Lunch is a full one, with salad and palak musts on the menu. “I stay healthy by not eating anything fried or cooked outside home,” he lets on.

At 5pm, he is ready for his evening walk at Victoria Memorial. “He walks so fast, I have to run to catch up,” complains Dubey, his man Friday.

Agarwal is not as fit as he once was but he still does not suffer from the Calcutta chromosomes of “cholesterol, sugar and pressure”. The greatest joy of longevity? Getting to be with his many great grandchildren. “My eldest great-grandchild is 20 years old and the youngest was born a few days ago.”

So what keeps these golden oldies going? P.K. Pooviah, a consultant geriatrician who is on the medical board treating Jyoti Basu at AMRI, puts it down to “healthy living in younger years”.

“It’s not rocket science that simple things like control of body weight, avoidance of smoking, balanced diet and regular exercise keep the body fit for longer,” says Pooviah, adding that “as long as a person feels that his mind and body are adequate for functional purposes, he is fine”.

No wonder Debabrata Ghosh Dastidar feels fine. The man with three great-grandchildren is still alert and alive to the world around him.

“Jyotibabu is two months younger to me,” declares the nonagenarian who worked for the ministry of defence (arms and ammunition) for 32 years.

“At 82, I went to Canada alone. And at 83, I used to board a bus to play bridge at the Calcutta Union Bridge Club,” he says proudly, his hands reaching out for a cup of tea. And no, his fingers don’t tremble.

Ghosh Dastidar’s diet is restricted and frugal, but with one indulgence. “A rosogolla or sandesh after dinner,” he says with a toothy grin. And no, the teeth aren’t false.

His theme song at 95? He promptly breaks out into the Uttam Kumar-Suchitra Sen road romance, “Ei path jodi na shesh hoye, tobey kemon hoto tumi bolo to…”

Do you know of an active nonagenarian? Tell ttmetro@abpmail.com