When Northland man John Clarke hits the pavement to train for the ASB Marathon and his muscles begin to burn he feels grateful.
The pain means he's still here to feel it - thanks to a fortunate chain of events that saved his heart from stopping forever during an ocean swim just over a year ago.
"When I'm running, feeling pain, I just feel so lucky that I can actually feel the pain and it sort of spurs me on."
Clarke was only 52, when he participated in a mid-winter ocean swim at Paihia in June last year and had the heart attack - 100m from the shore.
"Basically as I was swimming around the bit where you turn around, my wife went past and asked; 'what's the matter?'
"Apparently I said I was tired, a few moments later I was floating on my back, then the next thing you know I was face down in the water."
Wife Ann Clarke was also swimming in the race and said for her the first few moments were all about keeping him afloat and getting him to safety.
An off-duty firefighter who happened to be nearby in a boat hauled her husband onboard and began CPR and took him to shore. An off-duty paramedic who'd stopped with his wife at a café for a cuppa saw the emergency and ran to his car to get a defibrillator which he used to re-start Clarke's heart.
"Once he was on the beach and they were working on him, you can imagine, I thought I'd lost my husband," Ann Clarke said.
"It was very, very traumatic."
The couple credited the quick actions of those who jumped to his aid for the fact he's not just here - but fit enough to run a full marathon.
"It was just pure chance, if they hadn't done that I wouldn't be here," said John Clarke.
He remembered little about the day that could have been his last.
"I remember driving there," he said.
"Next thing I remember was waking up in the ICU and the nurse asking me if I knew where I was."
A few weeks in the ICU, one quadruple bypass surgery later, followed by a few months of rehabilitation which gradually turned into more serious training for the marathon and Clarke is in good form, with little, if any residual effect from his heart attack.
"I never took it easy, they'd say: 'oh walk 200m', but I was walking about 3km.
"It is pretty amazing really. I don't know how I'm here as I am now; I feel better than I did before."
He's running for the Heart Foundation with a goal of raising $3000 for the charity.
Clarke hoped it would help raise awareness about cardiac disease, how to administer CPR and where to get a defibrillator.
He said what happened to him, could have happened to anyone.
"I was 52 at the time and was fit and healthy. I had no obvious signs of any heart problems. My blood pressure had always been good and I had low cholesterol."
Support John and the Heart Foundation through here.
ASB Marathon 2016
October 30 2016
6am start time at King Edward Parade, Devonport
• Heart disease accounts for 30 per cent of deaths annually
• Every 90 minutes a New Zealander dies from heart disease
• Almost one in 20 adults have been diagnosed with heart disease