May 27 was a beautiful day for a run in Lindon, Utah. The temperature reached 77 degrees, and the snow-capped Rockies, framed against a cloudless sky, formed a scenic backdrop.

But you could hardly blame James Lawrence, a 45-year-old Canadian American who lives in Lindon with his wife and five children, for not basking in it. He was in the middle of his 87th marathon in 87 days. And those marathons were all the final segments of full-distance triathlons, each made up of a 2.4-mile swim, a 112-mile bike ride and a 26.2-mile run. His shins had started hurting around Day 4, then that shin pain moved up to his knee, up to his hip and down into the other shin. His toenails had fallen off, regrown and fallen off again.

To say nothing of the blisters.

Billing himself as the “Iron Cowboy,” Lawrence aims to conquer 100 full-distance triathlons in 100 days. Set to finish Tuesday, he has said he wants to push the limits of human endurance while raising funds for an organization that claims to fight human trafficking.

His plan is simple, if maniacal: He hits the local pool at 5:30 a.m. and swims for about 90 minutes. Then he hops on his bike for a loop around Lindon that takes five or six hours. Then, after a break, he starts his daily marathon, which normally takes around seven hours. It all adds up to about 15 hours of daily exercise, which supporters can, and do, follow online or even in person.

But controversy has trailed him, too. Ironman, the corporation that owns the majority of triathlon events worldwide, has urged Lawrence not to use its brand name. Some triathletes have criticized his use of IV injections to stay hydrated, because a dose of more than 100 milliliters in a 12-hour period would be prohibited in a World Anti-Doping Agency signatory event. (WADA, which has no jurisdiction over Lawrence’s event, declined to comment.)

The beneficiary of his fundraising is controversial, too: Operation Underground Railroad is a nonprofit supported by former president Donald Trump that claims to fight human trafficking. It is under investigation by Utah prosecutors after reports surfaced of it falsely claiming credit for the results of operations. (In a statement, the organization said it followed the law and would cooperate with any investigation.)

Last month, on Day 87, Lawrence answered a video call wearing a red T-shirt, camouflage shorts, electric blue shades and a baseball hat. He was in the middle of that day’s marathon; some supporters flanked him as he walked. He quickly switched off the video and answered questions with the economy of a man in conservation mode.

He felt “fantastic,” he said, but wanted to “only focus on the positive things,” such as “good times with family.”

Those have been harder to come by lately. In an interview, his wife, Sunny, said Lawrence is “perfectly miserable and ready for this thing to be done.” He is “always in pain,” she said, “and there’s always something that bothers him. He didn’t even start taking any pain relievers until two weeks ago.” He’s been walking the marathon since Day 3 or 4.

He knows well how to endure pain and carry on. He’s a former wrestler turned golfer who tried, unsuccessfully, to go pro. He started his endurance sports career with a four-mile run in 2004, followed by a marathon, then triathlons. In 2010, he set the world record by completing 22 half-distance triathlons in 33 weeks. Two years later, he completed 30 long-distance events in one year.

Sunny says his mental resilience has roots in wrestling and golf, but she adds that she never saw anything in her husband that showed such toughness until they lost their mortgage business — and their house and their car — in 2010.

“I hadn’t seen anything in our marriage to show any sign of mental grit until we hit the recession,” she said. “That’s when we had to pull together and, when he went into triathlon, saying he wanted to do some crazy stuff.”

In 2015, he took on a seemingly impossible challenge: 50 full triathlons in 50 days in 50 states, which he said he did to increase awareness of childhood obesity and raise money for the now-defunct Jamie Oliver Foundation. Lawrence, who now makes a living as a professional speaker, came under fire because the link for donations on his website didn’t work, though the foundation later confirmed it received the funds. The physical and logistical nightmare was portrayed in the documentary “Iron Cowboy: The Story of the 50:50:50.”

The 50:50:50 feat drew admirers and critics from across the triathlon community. Because of severe weather and injuries, Lawrence was forced indoors, completing some of the distances on stationary bikes, treadmills and ellipticals. That didn’t please hardcore triathletes, who thought doing a marathon on an elliptical shouldn’t count. Guinness World Records wouldn’t ratify his feat for reasons that are unclear. His use of IVs drew critics, too.

After 50:50:50, he competed in more endurance events, including running 235 miles across Greece, cycling atop Mount Kilimanjaro and competing in the Xtri World Championship in Norway.

For the Conquer 100, as he calls his newest challenge, he knew he couldn’t train in the traditional sense. So he tailored his preparation: a consistent volume of swimming (three or four times per week), a high volume on the bike and a lower volume of running (one or two times weekly) topped with strength training. He planned for his first 10 days to be the training base for the second 10, the second 10 the training base for the third 10, and so on.

Equally important are his recovering protocols: supplements, anti-inflammatories, massages, hyperbaric chambers, compression boots, red-light therapy. And the fuel: On an average day, he consumes around 6,000 calories, in small portions every one to two hours, though Sunny said they no longer keep close track.

Lawrence decided to stick with IVs for Conquer 100. Once per week, two if it’s hot, he pumps into his body a mix of “amino blend, magnesium chloride and vitamins C, B12 and B complex with double doses of L-carnitine and vitamins B5 and B6,” as the company providing the concoction says on its website.

Some athletes don’t begrudge his use of them. “I mean, he’s trying to survive this thing, and he’s not going against any other competitor,” said Dave Scott, a six-time Ironman world champion between 1980 and 1987. “But he kind of turned himself into a sort of manufactured robot, and he’s not really doing it out of his human physiology. And that could jeopardize the whole project.”

Scott, who suffered from a heart arrhythmia a few years ago, added: “When you’re doing 10, 50 or 100 Ironman, it’s survival. It’s very destructive for his body.”

Triathlon coach and YouTuber Taren Gesell called it “silly that vitamin and hydration IVs are disallowed for endurance athletes,” explaining that during training as much as 80 percent of the stomach’s blood supply is shunted away into the limbs, causing digestive problems. “He’s spending most of the day in a state where his stomach isn’t functioning well,” Gesell said. “His use of IVs is a smart safety precaution.”

But there are reasons WADA bans them in competition, said Kristen Dieffenbach, associate professor at West Virginia University’s College of Physical Activity and Sport Sciences. “There are always risks and concerns with infections and problems with any use of an IV,” she said. “But more so, it is such a concern to push health limits to need an IV.”

Iñigo San Millán, coach of 2020 Tour de France winner Tadej Pogacar and assistant professor at the University of Colorado School of Medicine, agreed. Conquer 100 is “an aggression and a torture to the body that may have lifetime consequences,” he said. But from a performance standpoint, he doesn’t believe IVs make a difference. “The amount of calories and a good digestive system would,” he noted.

Lawrence said he wouldn’t discuss the IVs or other controversial topics with a reporter — at least not during the event. Sunny said she wasn’t worried about what they signaled about her husband’s health.

“He is walking around all day with a lower heart rate than somebody with high pressure,” completing his efforts at very low intensity, she said. And she added that the “IV is not necessary; it is a bonus … an ‘insurance policy’ to cover the gaps.”

Despite uncertainty about future events, Sunny and James know something for sure: The window for extreme events is probably closing for the 45-year-old. Yet for endurance athletes, there is often something else around the corner. “At any time there is a surprise idea,” she says. “So I just go with the flow and adapt.”

That sunny day last month, James said he was looking forward to resting. Also? “Turning the phone off and not talking to people,” he said. He hung up not long after that and kept walking.