He was born with a hole in the heart and a missing heart valve.

At age five, doctors inserted a shunt into his body to aid blood flow. Quek Siow Kiak went through another operation at 13 to insert a mechanical heart valve.

And after a biological valve from a human donor was implanted to replace his mechanical heart valve in 2012, the 48-year-old driver will be fit enough to take part in Aug 29-30's OCBC Cycle, in the 42km event called The Sportive Ride.

Yet, for most of his life, his physical disability had frustrated him.

When he was young, he often had to sit and watch his classmates play during physical education lessons in school.

He said: "Even if I tried to join them, I could play for at most 15 minutes before I have to stop. I would be panting heavily and feeling giddy. I might even faint if I exercised too much."

Unable to accept his limitations, Quek picked up smoking in his teens, puffing at least 10 sticks a day. He recalled: "I started to not bother about my health, and so I began to smoke and drink a lot.

"I also stopped taking medicine needed to thin my blood and prevent blood clots, because I had to take leave from work just to see the doctor and buy my medicine."

Then, in a chance visit to the National Dental Centre for a toothache in 2009, the dentist found out about his bad habits, and he was immediately warded at the National Heart Centre.

Said Quek: "The doctors said that my blood pressure in my right heart chamber was three times higher than normal, and my heart could stop any moment.

"I was scolded for not taking care of my health, but they also told me of the option of going for a homograft - replacing my mechanical valve with a human valve."

In 2012, Quek, who is married with a 17-year-old son, received a homograft after a suitable match was found.

He said: "I am very happy to have my doctors who would push me to go for an operation and recover.

"I had second thoughts on receiving a transplant from a human donor because I might contract a virus, but I was reassured that it will be thoroughly checked."

He has since quit smoking and is now an active sportsman. This year, Quek completed his first full 90-minute football match.

He said: "I cycle to work in Loyang from Pasir Ris every day. I'll also do a 70km ride, at a speed of 38km per hour, at least twice a week, with my friends or alone.

"I play badminton with my colleagues every Thursday. And weekends would be spent with my family or playing football with my team, the Central Warriors Veterans."

At this year's OCBC Cycle event, he will be riding as part of the SingHealth contingent for the second time, and he hopes to inspire people to live a fulfilling life. He said: "I am able to do everything that others are able to do because someone gave his organ to me.

"My life has changed after my homograft surgery, and I hope other people can live a fulfilling life and support organ donation."