Gillmer fought through heatstroke to finish the course in a time of 11 hours, 37 minutes and 15 seconds, after needing several extended rests at stations throughout his bike and run legs.

It was a long way off the time of 9:42.44 that the Bathurst triathlete had produced over the 3.9 kilometre swim, 179.5km cycle and 42.2km run at Cairns Ironman to finish third in the men's 40-44 years division.

But simply reaching the finish at the recent World Championships was a top effort from Gillmer after the heat got to him in a big way.

"It was just too hot for me. It hit 38 degrees halfway through the bike leg and that's where my body just shut down," Gillmer said.

"It felt like I was trying to fall asleep out on the ride. It started to get dangerous. There was no wind out there, which everyone thinks is good for Ironman, but I needed that wind to cool me down. I really suffered.

"I ended up finishing in 11 and a half hours, which is a little over and hour and a half longer than what it usually takes me to do."

Gillmer had ventured to Hawaii hoping to get near the time of 9:51.18 that he ran in his previous World Championships appearance back in 2016, and after emerging from the swim leg in a time of 58:17 he was progressing well towards that.

He had emerged from the ocean sitting 51^st in his age division and inside the overall top 250, but as heatstroke got to Gillmer on the bike he was passed by nearly 1,400 competitors.

The heat continued to eat away at Gillmer over the run, where he had to again stop at points along the course.

However, Gillmer had cheered on fellow Bathurst entrants Hollee Simons, Peta Cutler and Fran Grady in their race two days earlier and used their efforts as inspiration to push through to the end.

"What gave me a lot of strength was seeing Fran Grady out there on the bike for eight hours two days earlier. I was never not going to finish. You're in Hawaii at a World Championship event, and I was always mentally in it," he said.

"I never wished it away. I'm more proud of that than anything, because it's never been that hard.

"It hit me roughly 90kms into the bike. I was on track to hit all my targets, my fitness was good, and then in a short period of time my body just shut down.

"I pulled over the aid station about 110km into the bike, sat down, had a coke and was there for 10 minutes. I had to repeat that two more times to get home.

"The same thing happened on the run as well. I was either running strongly or just not functioning at all. It was really a mental battle the whole day. I've never shut down that bad."

Gillmer said the support from both friends and strangers on course is a wonderful mental boost when the going gets tough.

"Nick [North] and Hollee appeared out on the course with about 10km to go and that lifted my spirits, and I got running again for a little while," he said.

"Then with 5km to go there's people playing music and cheering a lot, and that drove me home. I also knew my little guy Andy and my partner Jenelle was waiting at the finish line."

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