Sports stars around the globe battle ailments in their occupation. Their infirmities are extensive and often hidden from the public gaze. Athletes such as John Kirwan have raised the public awareness of depression and others have revealed fights with anxiety, asthma or pain addiction.
Very few have suffered from the respiratory problem of cystic fibrosis and made it to the highest levels in their sport. Exceptions have been Canadian triathlete Lisa Bentley, professional wrestler Andrew Simmons and NCAA basketballer Nathan Gottlieb.
And then there's Nathan Charles. The Force hooker made his Wallabies debut this year against France and is set to start the opening Bledisloe Cup test in Sydney next week.
Charles' condition was diagnosed when he was just three months old and he pays tribute to his family who felt the best way to keep the disease at bay was sport.
"I'm very fortunate I have a mild case," he said. "For me, exercise is the best medicine."
It meant Charles substituted sport for the chest therapy most sufferers endure.
"I have to look after myself, otherwise you can deteriorate quite quickly, so it's about being on top of things, being proactive and doing everything you can to stay healthy."
Whichever way you dice it, Charles' ability to cope with cystic fibrosis, a genetic disorder that mostly affects the lungs, and rise to the top in such a physically demanding sport as rugby is remarkable. His journey to get there has been full of twists and turns.
A potted history shows he signed to play rugby league for the Bulldogs as a schoolboy with a clause that allowed him to get out of the deal if he made the national rugby side.
He stayed with union after making the Australian schoolboys in 2006, went to the Brumbies in 2008-09, from where he was picked for the national under-20 team, then signed for the Force in 2010.
With new captain Stephen Moore out for the year and his deputy Tatafu Polota-Nau sidelined by injury for next week's test against the All Blacks, Charles will wear the No 2 jersey for Australia.
Wallabies coach Ewen McKenzie has enormous respect for Charles.
"If you look at the symptoms, and classic symptoms of cystic fibrosis, it's not a great scenario from a sporting point of view, but he seems to have defied science and defied logic," McKenzie told Sydney media. "One of the issues might be putting on weight but he seems to have no problem. He looks like a hooker and he's got the right proportions."
Charles, who stands 1.83m and weighs 104kg, is not alone. His girlfriend Verity Simmons plays netball for the Queensland Firebirds while she juggles daily insulin injections for type 1 diabetes.
The 25-year-old must also take medication daily to sustain energy levels for not only sport but also his duties as a national ambassador and fundraiser for his affliction.
"If I can be an inspiration and role model to some people, I'm extremely humbled by that."
In June, Charles made his debut against France and gets his chance for more against the All Blacks.
"It's a goal I've had since I was a kid. To have that opportunity and take it with both hands was an exciting prospect and I just want more. It's quite addictive."