(CNN) – Lucy Gossage is an expert in suffering.
A cancer doctor by qualification, she has also become a specialist in the brutal discipline of Ironman, which consists of a 3.86-kilometer swim (2.4 miles), a 180.25km bike ride (112 miles) and a marathon to finish.
On Saturday, she will line up against the best in the world in Hawaii for the World Championships.
But she makes it clear that the pain barriers in the medical and sporting fields are worlds apart.
“I think the thing I find helpful when I’m hurting in competition is that I’m choosing to suffer,” she tells CNN via a telephone interview from Kona just 48 hours before the race.
“There are a lot of people, including cancer patients, that go through pain but don’t have a choice.
“I have a choice, I can make it stop. I’m doing it because I want to do it. The pain is simply proof that I’m doing it to the best of my ability.”
That Gossage will be on the start line at all is a testament to her propensity to withstand pain, competing in the most punishing of events just two months after breaking her right collarbone after a bike accident in training.
While waiting for surgery, she tried to continue training to test the extent of the injury.
“I remember there were builders outside on the pavement and I already looked a sight in a bikini with my arm strapped to my side,” she recalls. “I set off for 50 meters, the pain was so bad I was nearly physically sick. I must have been quite a sight.”
She slowly built up the exercise, swimming lap after lap of her local pool with her arm strapped to her side, riding her bike and then pounding the streets when the pain subsided sufficiently. For a time, she even tweeted with the hashtag #downbutnotout
She has toiled hard just to make it to the start on Saturday but if it wasn’t for the injury she might have been climbing up the rankings.
A year ago, in brutally hot conditions she finished in the top 10 overall against the best Ironman triathletes in the world. Now, she has no idea how she might fare.
“It’s like having a box and having no idea what’s inside it,” she says. “I’m quite nervous about the pain as I’ve shown in the last few years I hurt myself a lot in races.”
Gossage likes to recall her early teenage years to show how far she has come. She remembers running in a cross-country race and coming in dead last, hardly a beacon of the sporting prowess that lay ahead.
“I think that put me off sport … I didn’t do anything competitively for a while.”
And the triathlon only became an event for her 11 years ago when, with the relationship with her then boyfriend splintering, she thought why not.
A chance encounter with a medical student, who had done an Ironman, led to a conversation on the subject. She decided that if she was still single by New Year’s Eve that year she would tackle an Ironman.
She found that she both enjoyed and excelled at the most punishing of sporting disciplines.
She is a two-time Ironman UK winner and has a string of victories at events at home and abroad though she admits to struggling to belong among the world’s elite.
Even though she has been a professional athlete for two years she returns to medicine in November with a part-time job as an oncologist.
“I’m excited but I’m terrified,” she admits. “Will I still be a good doctor?”
She has missed the clinical side of her work and being with patients. But she insists that the experience of seeing others suffering is not as daunting as one might imagine.
“A lot of people think it’s impossibly depressing but it’s not,” she says. “I love it. It’s sad obviously at times but it’s not depressing. I enjoy building up a relationship with people experiencing very tough times in their lives. You get an opportunity to build up a very special relationship.”
She believes that after battling injury and returning to her medical work, she will appreciate the Hawaii competition even more.
“I’m doing something in my life I never thought I’d do,” she says. “It dominates your life and it takes so much out of you. There’s mental and physical pain, and the mental pain is as tough as the physical pain. But for all that, I love it for that feeling at the finish … and if you’re not hurting you’re not pushing yourself.”