Ironman in his blood from day one

Aucklander David Knowles is competing in the 30th Ironman anniversary event on March 1 after taking part in the inaugural event in 1985

David Knowles couldn't help himself. The 50-year-old from Auckland, who took part in the first Ironman NZ in 1985, wasn't going to miss the 30th anniversary of the Kellogg's Nutri-Grain Ironman NZ for the world.

He will be one of a record 1760 competitors taking part in the gruelling three-discipline event - involving a 3.8km swim, 180km bike ride and 42.2km run - in Taupo on March 1.

After Knowles competed in the inaugural event three decades ago, he went on to qualify for the World Championship in Hawaii in 1989 and 2008.

He is familiar with the milestone years of the world's signature endurance event after completing the first, 10th and 20th Ironman NZ events before taking a break from the sport after 2008.

"It's been six years since my last one, I just wanted some time out," said Knowles. "It's the challenge and knocking out the milestone years that brings me back."

Knowles says running around the scenic Taupo course is the part he always looks forward to. "Running is my favourite. It comes a bit more easily to me. The swimming's always a bit daunting."

As for training, he says he covers all bases. "I do just the usual swim, bike, run, and long sessions on the weekend."

The seasoned competitor has no plans for retiring from triathlon anytime soon.

He is already lining up to be on the start line for the 50th anniversary - when he will be 70.

Knowles encourages people of all ages to take part in Ironman events, after personally making gains over time and improving his personal best in the sport. "My fastest time actually came 24 years after my first effort at Ironman."

Ironman New Zealand event director Janette Blyth said that David and his wife Alison typified how Ironman could become a lifestyle for regular competitors.

"David has been involved in the sport from day one. He and his wife enjoy a healthy and active lifestyle, and he has been able to enjoy Ironman in and around his business life," she said.

"He has also played a strong role and been a strong supporter of our organisation over the years in other events, and I am sure will be on the start line for the 50th."