Powell, a registered nurse, began having health issues in May last year when he became breathless while walking up the hill on Hospital Rd.
He ended up having a quadruple heart bypass last June after tests at Auckland Hospital revealed his arteries were 90 per cent blocked and he was told he had just hours to live.
He was admitted to the cardiac ward and his bypass surgery was fast-tracked. Immediately after the surgery, Powell found it difficult to move at all but he was determined to recover his fitness.
"It took me seven minutes to get out of the bed and into the chair. Then I looked out on Park Rd at all the runners and I thought, 'Hmm, maybe I'll join them'."
Powell's recovery was fast, and he was soon back to a normal routine - quicker than most patients.
"I was back to work after eight weeks - full-time," Powell said.
"The cardiologist said 'You're the kind of guy we write in medical journals about'."
Powell wanted to acknowledge the help of the cardiac rehab team in his speedy recovery and return to fitness. He has done no specific training for the Dargaville event, but was always walking.
"I'm doing exercise all the time and whenever I walk, I walk fast."
The scar on his chest was now virtually invisible, and he has walked up Mount Maunganui and built a fence in the year since.
Powell was hoping to complete the event in about an hour and a half, based on his walking time of about 7km/h.
He used to be a long-distance runner, and his wife, Janice, is "one of the fastest women in Whangārei".
She has previously won the women's section of the Kaitāia Walk/Run event in 2012, was third in Kaitāia 2015 and third in the Beach to Basin in March this year.
She would also be entering the Dargaville event on Sunday, Powell said.
The 62-year-old said he would probably not return to running - it's too hard on the knees - but planned to enter more walking events. He is determined to stay fit and eat healthily to avoid a relapse.
"I really feel very lucky to be alive ... that never goes from my mind that I nearly died."
The Dargaville event is part of the Sport Northland Run/Walk Series, and has 10.5km and 5km options.