Schoolchildren are being encouraged to run one mile a day to benefit their physical and mental well-being.
The Daily Mile is aimed at getting children active, reducing sedentary behaviour, increasing fitness and improving body composition. and all can participate.
Children can go at their own pace and the non-competitive run takes around 15 minutes.
Holly was diagnosed when she was just five weeks old but she walks to and from home school, as well as running a mile on a daily basis, which her mother believes benefits her health.
Millie, Holly's mum, told ITV London: "Running has become a real passion for her and it really finds keep her lungs clear. It's another session of physiotherapy that she's able to do outside of the home environment.
"It's also about trying to encourage a healthy lifestyle that children can take into adulthood by doing these sorts of activities which cost nothing that you can just bring into your day to day."
Holly believes the daily exercise is having a positive impact on her and her condition. She has joined a local running club and finished third in the Westminster Vitality Mile recently, out of many hundred of children.
Holly: "I like running with my friends. The difference is before I was running my chest was tight and after my chest was loose."
St Monica's, where Holly goes to school, installed a track for pupils to run round and the teachers are reaping the rewards in the classroom.
Kate Baptiste, headteacher at St Monica's, said: "We get a PE grant, all the schools in the country get a PE grant, so we had The Daily Mile track put in in February of this year and it was instantly a hit with the children.
"You could see when they come in the morning, they would be running around, the parents also joined in.
"The hard work makes them a bit sleepy or they can be a bit tired, a bit of exercise (they're) immediately invigorated, the energy levels go up and I think in terms of the mental health and well-being, that a lot of them enjoy it. It's calming activity, it's a relaxing activity, they can just let their thoughts go when they're running around."
For more information go to The Daily Mile's website.