A woman with halved lung capacity is training to run the London Marathon to help prevent future generations dying from her disease.

When she was 18 months old, doctors told Sharee McPhail's parents she would be lucky to reach her 20th birthday because she had Cystic Fibrosis - a genetic disease affecting the lungs and digestive system.

Miss McPhail, of Moser Avenue, Bradford, is now 23 and is aiming to raise £2,000 during her marathon run for the Cystic Fibrosis Trust.

She said: "This may not save my life but it may help to save the lives of future generations born with Cystic Fibrosis.

"I have a lung function of 49 per cent, so I guess you could say it's like running with one lung, so it will be a huge personal challenge for me.

"Training is a slow process, I cannot just get on a treadmill and start running, I have to work my way up. But even if I have to crawl over the finish line, I will finish it."

The disease opens the body to frequent infections, and it was one of these that Miss McPhail caught at 16 which damaged her lungs. A keen dancer, she attended Footsteps Theatre School in Bradford for nine years, but her limited lung function has reduced the amount of dancing she can do.

She said: "It took me a while to come to terms with it. I had to slow down the amount of dance classes and exercise I was doing because I just didn't have the energy.

"I attend the gym and tend to push myself as hard as I can but it's not easy as I become breathless quite easily."

She takes 20 tablets a day, including antibiotics to fend off infection.

She said: "I have grown up with this and it is just part of my life.

"I have always tried to live my life as normally as possible and not allowed my condition to get in the way of anything I do."

Miss McPhail, a receptionist at Fitness First Gym in Eccleshill, Bradford, needs to reach her £2,000 target before the 26-mile-plus marathon on Sunday, April 22.