The London Marathon would have people half David Coley's age shuddering but the spritely 63-year-old is getting ready to run his fifth this weekend.
Coley, a member of Rushmere Baptist Church, aims to complete the marathon this year in four hours and 15 minutes.
It will be rewarding to make his target time, but not nearly as rewarding as knowing his efforts are raising vital funds for a new therapeutic centre to help women in the Ipswich area beat alcohol and drug addiction.
The centre is being built by the Christian charity Talitha Koum on a farm just north of Ipswich.
Coley has lived in Ipswich for more than 30 years and is a member of the Ipswich Jaffa running club, Ipswich Triathlon Club and the Felixstowe Road Runners.
He is "delighted" to be running the London Marathon this year for "one of the most deserving charities in Suffolk".
"Talitha Koum aims to help women beat their addictions and associated problems, a charity that came to prominence following the five murders in Ipswich in 2006," he said.
"As a father of daughters I know how women were affected during the murders, how they were afraid to venture out at night. It therefore gives me great joy to run to raise funds for this place of therapeutic healing."
John Cobbold, chief executive of Talitha Koum said: "We all we need to come alongside these vulnerable women with a heart of compassion to help them beat their addictive behaviour, and leads to their reintegration into the community."
The Right Reverend Nigel Stock, Bishop of the St Edmundsbury and Ipswich Diocese, and the charity's patron, said: "It has been very heartening to see the way that the Talitha Koum project has caught the imagination of so many people and the organisations they represent.
"There has been remarkable progress on making the vision become reality, even though this is all being done during a time of severe economic recession.
Preparatory building work has started on the site of the new centre and local people have being showing their support with their own fundraising efforts.
Steve Jay, pastor at the Hope Church in Ipswich and a grandfather, jumped from a plane at 15,000 feet to raise money for the charity during a tandem skydive in north Lincolnshire.
To sponsor Coley in the London Marathon visit https://mydonate.bt.com/fundraisers/davidcoleylondon