At 3am last Friday morning, Hastings triathlete Brendon Vesty lay writhing in his bed at home due to excruciating pains in his abdominal area.
Mercifully, what had all the telltale medical signs of appendicitis was later diagnosed as a bowel infection which still left Vesty feeling like a spent boxer after 12 gruelling rounds, thanks to a potent cocktail of antibiotics.
It was a wake-up call that had jolted him out of his comfort zone to steer him all the way from his blood-testing general practitioner to the emergency department of the Hawke's Bay Regional Hospital in Hastings the next day.
"I had some severe tummy pains and I just couldn't sleep for the rest of the night," says the 46-year-old.
He spent a night in a hospital bed and was discharged at 10pm after scans last Sunday before boarding his flight on Wednesday to his maiden Kona Ironman Championship in Hawaii on Sunday.
"I had a fever so I thought it's just a tummy bug and I'll be all right."
What had been a dream, if not flawless, build-up to the "Tour de France of triathlons" had rapidly turned into a nightmare for the co-director of Stortford Auto Sales.
Vesty, who had been preoccupied with the gritty course heading down Alii Drive, then along the Queen Kaahumanu Highway to the Energy Lab and back in Hawaii, was now threading his worry beads on what the test tubes and vials at the medical laboratory at home were trying to tell him.
"The doctor had done some blood tests and I got them at 5 o'clock and she said everything's pointing to appendicitis," he says. "All my markers were high and my white blood-cell count was up there so, obviously, my body was trying to fight off an infection."
It didn't help when a nurse suggested he should simply have his appendix taken out.
His two years of sacrifices and commitment to an ambitious campaign had flashed across his mind. He erred on the side of caution, with two weeks of recovery a given and any form of competition out of the question.
"I wouldn't have been able to travel and I would have had to spend two to three days in hospital even though it was key-hole surgery."
No matter how savvy he was as a former professional cyclist, this medical episode had pushed him right into the witness box of self-cross examination to question his constitution.
Almost instantaneously he got swept away in a wave of selflessness amid all the mounting levels of anxiety and stress.
A CT scan at 9pm and a radiologist's report another hour away, amid all the preparatory surgical work while waiting, but a smiling registrar at 10pm had put him on cloud nine.
"For me the main thing was letting the kids down, I guess, because they are pretty excited about this holiday and then having to say to them that we can't go now," says the father of four with a wry smile.
Partner Jessica Harris and children Karsen Vesty, 14, Sofia Vesty, 12, Sage Harris, 8, and 2-year-old Noah Vesty will accompany him during his campaign before a break in the United States on the way back home.
"You know, there are other races and it's not the be-all-and-end-all of things but it would have been devastating for me not to race."
Vesty says it would have taken enormous resolve to pick himself up had he missed out on Kona and let his family down.
Nevertheless, his experience, which brought him a "no training, please" notice from coach Jina Crawford, of South Island, has taught him a few life lessons.
"I'm now travelling to Kona, starting the race and I'm hoping everything will be okay."
Last Thursday night, at the regular Hawke's Bay Ramblers Cycling Club 17km time-trial race he had produced his "best wattage" (FTP, functional threshold power) in the last 12 minutes.
"It was a great indicator that I'm fit and ready to go."
While he instinctively got back into the saddle of his bike, Vesty had still felt a modicum of tightness in his muscles which meant running wasn't an option.
No doubt, he has revisited his goals at the mother of all triathlons where he is gunning for a top-10 finish in his 45-49 male age-group category, amid reports Kona is bracing for a hotter than normal time of the year.
"Because I've had a big scare and thought I wasn't going to do it I'm now just glad to be there and the result isn't important."
Instead, he is recalibrating his biological instruments to achieve some personal-best times in the three disciplines.
"I could have a great run and be on the podium but, realistically, I would happy to be in the top 10 and perhaps with another year of experience go back for another shot."