Nick White, from Loughborough, has already raised £1,900 in sponsorship ahead of the event, on April 23 – so now all that's left to do is run it!

It will be the first time that Nick, 45, has ever run a marathon.

"I chose the Joe Humphries Trust because I am a keen amateur swimmer and swim for Loughborough Town Swimming Club, where Joe was a member, making his trust particularly important to me," Nick said.

"The work they do could save the life of one of the young sportspeople I train with on a regular basis.

"I've been running for about two years now, and I've been training hard, four to five days a week for the past three months. It's been hard to keep up with my swimming and fit in the long runs as well.

"I'd be really happy to finish in under four hours, but I'm more interested in enjoying the experience and the atmosphere on the day. My partner, Karen, and son Alfie will be cheering me on.

"I am very proud and honored to be running for this wonderful charity, and would like to thank everyone at the Trust for giving me the opportunity. I would also like to thank everyone at Charnwood Athletics Club and coach Stuart Walker for all the help and advice they have given me."

The Joe Humphries Memorial Trust (JHMT) was set up in memory of Leicestershire teenager Joe Humphries, who collapsed and died while out jogging. Joe was a victim of sudden arrhythmic death syndrome (SADS) – a group of lethal heart conditions and diseases which can cause sudden cardiac death in seemingly fit and healthy young people.

Since Joe's death in 2012, JHMT has campaigned tirelessly for greater understanding and awareness of SADS, as well as providing vital life-saving CPR training for schools and sports clubs.

The Trust also runs an awards scheme called Inspire aimed at helping young people to fulfill their potential by providing small grants for sporting, arts and community endeavours.

Steve Humphries, chair of JHMT, said: "Nick's efforts on behalf of our charity are simply fantastic. Not only is he completing a significant personal challenge, but with every step he takes along that 26.2mile route he'll be helping us to raise awareness of the dangers of undiagnosed heart conditions and diseases like SADS.

"These conditions claim the lives of 12 seemingly fit and healthy young people, aged 12-35 years old, every week in the UK, but these deaths are not inevitable. They're preventable.

"If more people – including young people of school age – knew how to start CPR and get a defibrillator to someone within a few minutes, we could really make a difference to those figures."

To find out more about the Joe Humphries Memorial Trust, please visit http://jhmt.org.uk/

To sponsor Nick, go to http://uk.virginmoneygiving.com/fundraiser-web/fundraiser/showFundraiserProfilePage.action?userUrl=NickWhite16.