Kevin Paterson from Seaham was an experienced runner, who finished his first half marathon - the Great North Run - when he was ten years old. He was apparently fit and healthy when he started another half marathon, the Great Birmingham Run, on October 21st this year.
However, after he crossed the finish line, a steward noticed he looked unwell. Minutes later, he collapsed, and he died later in hospital.
"Kev was a family man, mostly, and a brilliant friend to everyone who knew him. He was competitive, loyal and generous," said his sister Laura Bartley. "An amazing brother. And everyone who knew him loved him."
After his death, his family set up a tribute page on the internet, and asked for donations to charity. In two days, they raised £2500. Now they have decided to continue fundraising, by gathering a large group of his friends to run the same race next year.
Laura said: "Something positive must come out of this. It has been such a shocking and heartbreaking time for us.
""We are going to get t-shirts with his name on and it is all going to be for Kev. We're going to raise as much money as we can and hopefully some people will benefit out of this.
"He would be over the moon if he knew. He would be really proud of us."
To contribute to the family's chosen charity, see the fundraising page set up in memory of Kevin Paterson.