To win the 2018 XTERRA World Championship, Lesley Paterson first had to beat Lyme disease.

It was 2010, and Lesley Paterson couldn’t figure out why she was so damn tired. She was having a breakthrough year in triathlon, building off a silver medal at the XTERRA World Championships and a win at the California International Triathlon. She was, technically, in the best shape of her life. So why did she feel so awful?

“I was so fatigued all the time,” recalls Paterson. “I had some days when getting out of bed seemed to be impossible.”

At first, she chalked it up to a byproduct of heavy training. But soon, her fatigue was joined by other unusual symptoms: a relentless eye twitch, random head tics, and what Paterson calls “incredible nausea.”

“I just knew something wasn’t right,” says Paterson. “It was different from anything I had experienced before.”

Just before visiting her physician for a check-up, Paterson mentioned her symptoms to a friend.

“Lesley,” she said urgently, “You need to ask your doctor to test you for Lyme disease.” As it turns out, this friend had experienced almost identical symptoms and struggled to receive a correct diagnosis right away. She wanted to save Paterson from that same fate.

“I didn’t even know what that disease was, but decided to ask for the test anyway,” says Paterson. “I was shocked when it came back positive.”

Lyme disease, an infection spread by tick bites, usually starts with a rash on the skin. As the infection spreads, the rash disappears and the symptoms become more generalized in the form of extreme fatigue, headache, joint pains, and neurological symptoms. Paterson was surprised—she hadn’t recalled a strange rash at any point in her life—but as her doctor explained more about Lyme, her other symptoms began to make sense.

The good news: Lyme disease was treatable. The bad: Even after the infection was treated, Paterson would likely have chronic symptoms from an autoimmune reaction to the disease.

“You never really get rid of it,” explains Paterson. “You just manage it and get it in remission.”

For example, the nausea Paterson was experiencing was the result of a coinciding infection in her digestive system known as Small Intestinal Bacterial Overgrowth—Lyme often causes symptoms similar to Irritable Bowel Syndrome (a common misdiagnosis in people with Lyme). Even after her diagnosis and initial treatment, which included four months on antibiotics, Paterson would continue to experience nausea and unpredictable bouts of extreme fatigue.

“It’s so arbitrary,” says Paterson. “Anything can trigger symptoms, and you can go crazy trying to figure out the cause of a flare-up. I could be training great while getting ready for a race, and then all of a sudden the night before, I’d have a flare-up and feel dreadful.”

This was a big reason why Paterson’s triathlon performance over the past eight years has been such a rollercoaster. When she’s on, she’s on—her 2011 and 2012 XTERRA World Championship wins are evidence of that. But when symptoms rear their ugly head, as they did for most of 2014, she can barely get out of bed, much less train or race. The inconsistency and instability of her symptoms began to cause depression and anxiety for the usually-optimistic Paterson.

“I didn’t know what this would mean for my athletic career,” says Paterson. In 2014, during a particularly long and difficult flare-up, she decided to take control. She recruited the help of specialists in Florida, California, and London, who have constructed a strict regimen designed to help Paterson return to health. She told them she was willing to try anything, and she made good on that promise.

“I’ve gone through phases of doing saunas every day for several months,” says Paterson. “I’ve been on and off herbal regimens since 2011. I do daily meditation and take focused rest periods where I put on weight and take long stretches off training.”

Though the symptoms improved somewhat, they still persisted—particularly, the inflammation in her digestive system. In 2017, on the recommendation of her doctors, Paterson underwent a Fecal Microbial Transplant.

“Basically, for two weeks, I had a donor’s poo put inside my intestine,” Paterson explains. “It allowed me to adopt their microbiome, given how bad mine had become.”

She knows the procedure sounds crazy to most people, but she was willing to do anything to feel better. It worked; as the donor’s microbiome began to take over in Paterson’s gut, her energy levels went up and symptoms were reduced significantly. Today, she has to follow a strict autoimmune protocol diet to maintain her microbiome (“If I eat anything outside of the diet, I feel like I have the flu.”) Still, it’s a small sacrifice: Paterson is feeling the best she has in years. She credits the transplant as being a major piece in her ability to consistently train at the level required to return to the top step of the XTERRA World Championship podium after six years. The journey to health has been a long and difficult one, making her win all the more rewarding.

“This experience has changed my perspective in every possible way,” says Paterson. “It’s made me incredibly grateful for what I can do. When I have a good day, I’m so excited. When I have a bad day, I find the joy, regardless of where I am or what I’m doing. I know it’s making me mentally tougher. Because of this, I genuinely am so proud of any performance I give. Any race is a success.”