And for all of this, Barfoot blames his son. "I was always keen on exercise and did a lot of recreational tramping, but I was pretty much hopeless at all sports. In any sort of race you would find me last," he said.
"When I was in my mid-50s our son got interested in the Ironman from a teacher at his school. From there my wife Judy took it up and I had to follow suit. In fact, when Henry started volunteering at the Ironman when it was in Auckland, I had never heard of it. Now I've travelled around the world taking part.
"When I did my first one I remember the office knew nothing of the sport and posted that I had achieved an Ironman in 13hr 51min. I sort of achieved credibility by the length of time I was out there."
Triathlon in particular has struck a chord with Barfoot. "The fact it is three disciplines is great. Mostly it is easy on the body but if you get the odd injury that restricts you in, say, running, you can still swim and bike."
He loved competing in the inaugural Ironman 70.3 over the Auckland Harbour Bridge last month. "The course was just magnificent and great to compete at home. There were more than 1000 there for a first year so I think it will become very popular.
"I got second in my age group but I beat Mike Ramsay [who will tackle his 29th IMNZ finish in Taupo today] for the first time ever. I am sure to remind him of that. It's given me another good reason for living," he joked.
Barfoot is one of 1430 participants in Taupo today, and nearly all have a story to tell. Like Tony Herring from Christchurch - he broke his neck in 2010 and spent three months in traction at the Burwood Spinal Unit.
"I should have died or been a tetraplegic and dependent on a ventilator for the rest of my life, but I survived," he said. Herring not only recovered but is now attempting his dream to become an Ironman.
Angela Past is an art appraiser from Los Angeles. She is part of Team Type 1 from the United States who are keen to show that those who suffer from type 1 diabetes can do anything with proper care, diet and exercise.
Jonathan Smith is a demolition supervisor in Auckland. He has lost 60kg to prepare for his first Ironman, changing his diet and attitude at his workplace, trading meat pies for salads and nutritious meals.
Nick Bailey is an amputee from Palmerston North. He had his arm amputated after a forklift accident in Antarctica when he was 24. Now he owns and manages Action Indoor Sports Arena in Palmerston North, and is active in the Manawatu sports scene and promoting disabled sport in particular. This is a major tick on the bucket list for the 52-year-old.
Kathy Eggers, a nurse from Napier, suffers from chronic inflammatory demyelinating polyneuropathy (CIDP), a rare neurological disorder, and has experienced life as a quadriplegic. She receives regular blood transfusions and medications to keep stable. Her path began with IronMaori in Hawkes Bay, and now she is aiming for the ultimate dream.
The 29th Ironman New Zealand begins at 6.45am for professionals and 7am for age-groupers, with the winner expected by 3.15pm and a final cut-off at midnight.