"As fit as I've ever been, I just can't get my calves to race.
"You use all your energy in the first half, then in the second half you're just dead."
Edwards said he was surprised when he caught back up with Heather and told him as much when the Taranaki runner crossed the line a few minutes later.
"You gave it to me, brother," he said, shaking Heather's hand.
When they both had reached the last bridge turn the younger man's tank had hit empty and he was running on willpower alone at that point.
"I never saw him walk, I'll give him that, I would have walked," said Edwards.
"His anchor went out and I killed him."
Heather was still satisfied with his effort, which had been a learning curve.
"It was my first marathon, I'm reasonably happy with that.
"He [Edwards] went out strong and then I came back at him, then he came back in that final 5km. I could just feel the calves starting to tighten."
Heather said he will "definitely" be up for more marathons.
As well as the 91 full and three-quarter marathon runners completing three or four 10km laps from Somme Parade over the Dublin St, City and Cobham bridges, there were a multitude of other runners, young and old, in the 5km, 10km and half marathon races.
In total, the 605 entries overall was down on the record number of 709 achieved last year, although club captain Jimmy Hildreth said the makeup of which walkers and runners entered various events was different.
The 240 entries in the half marathon exceeded last year's number of around 200, with 99 people doing the 5km course and 175 completing the 10km event.
A number of competitors were possibly underestimating their abilities because as the various grades made their way to the finish line, the quickest of the 50km runners finished their dash in around 30 minutes, after starting just after 9.30am.
Around 15 minutes later the first of the 10km competitors crossed the line.
Some veteran club competitors had set off earlier than the 6.30am start for the long course walkers, allowing them to get through their event in the cooler morning conditions.