The Dunedin runner had to dig deep into his reserves to claim a world age-group title in the United States at the weekend.
Hayman, a 20-year-old university student and product of Otago Boys’ High School, won the men’s 20-24 years grade at the Xterra world trail half-marathon championships in Carrabassett Valley, Maine.
Parts of the event sound like something out of the imagination of Maine’s most famous resident.
Stephen King himself might have penned the description of Hayman’s "grim death stomp home" that was followed by vomiting and a collapse over the finish line.
Small wonder Hayman described the race as "bonkers", especially as he had battled a foot injury and illness in recent weeks that severely curtailed his preparation.
"The hardest thing about it has definitely been the buildup," he said.
"I've been trying to prepare for this event for the last six months and I've been repeatedly knocked down with injury and a couple of really nasty viruses only several weeks out.
"Even when we got over to America ... it hasn't been easy sailing with a combination of the travel and pre-race nerves that saw me eating next to nothing for the three to four days before the race.
"I'm really glad that my parents made the trip over with me because I don't think I would have been in a great state to race if they weren't here. Their support over the years has had a really massive impact."
The half-marathon, part of a festival weekend of Xterra events, took place over 22km of trail running based around picturesque Sugarloaf Mountain.
An initial 5km climb gained 750m in elevation, culminating in a summit view before a 1km descent and traverse across the mountain.
A freshly built trail then led to Burnt Mountain before descending into rolling trails and around a large pond then finishing in Sugarloaf Village.
Hayman was second to the top of the first hill but dropped a few places on the "gnarly, technical unmaintained track" that took runners back to the bottom.
It was "easily the hardest terrain I’ve ever run down — so much mud, tree roots and rocks", he said.
He was feeling good after pushing back towards the front of the field.
"Then I hit the wall and began a grim death stomp home for the final 4km.
"Not even 500m from the finish, I had to stop to be sick, but picked myself up ... and had a mad sprint for the line."
Hayman crossed in 2hr 15min 31sec, fastest in his age-group and seventh overall, but the effort took its toll.
"I spent a good 10-15 minutes collapsed on the concrete, making everyone a bit worried, and it’s taken several hours to feel OK again.
"One hell of a race."
Hayman had been targeting the world championships since winning his age category and finishing fifth overall at the Xterra European championships in Italy.
He has a bunch of university work to catch up on before he aims for the Dunedin half-marathon and joins some Leith clubmates for the national road relays in Taupo.
"Beyond that I have several half-ironmans planned for over the summer so I should probably get training for those."
