Running is the perfect tribute to a lost friend for 30-year-old physio Mark Hughes.

When my best friend Ralph Murwill did the Robin Hood Half last year, he was fit and healthy.  Ralph crossed the finish line in 1.51 - and died immediately afterwards. 

Sudden Arrhythmic Death Syndrome (SADS) is a disorder of the electrical system of the heart; it can kill apparently healthy people without warning.  Ralph was 28.  So when I run the Robin Hood Half this September, along with Ralph's brothers Phil and John, it won't just be for myself. 

I hadn't done any serious competitive running before, despite being a trained physio.  But Ralph, a fellow physio, had always encouraged me. 

We met at Brunel University.  the course was very female-dominated; there were four guys there, mostly just looking terrified - until Ralph bowled up and introduced himself. 

We were friends from then on.  We even went off to Africa together to volunteer in a hospital.  Running was our way of staying in shape, so we'd power through hot mountain runs.  When we came home, we got jobs in hospitals in the same area. 

Though we had done a few 10ks together by that point, it was still more Ralph's thing than mine.  He'd always wanted to do a marathon but I wasn't the slightest bit interested. 

On the day of the Robin Hood Half, I was meant to run too, but with a sore Achilles, I though, 'there's no point pushing it.'  So I said, "Good luck, mate, see you after," and the first I knew of a problem was when I got a phone call later that day.  It was surreal. 

I wasn't someone who would necessarily have handled this situation very positively.  Yet after the funeral, Ralph's family tried to make it all into a positive, to remind us that we were lucky to have known such a good bloke.  Friends and family were all doing things to remember him and running became my way of dealing with it.  It gave me a focus; something good to do rather than going out drinking. 

And of course, once I got into it, I loved it; becoming fitter, making friends and raising cash for Cardiac Risk in the Young (CRY), a SADS charity. 

I've had terrific hamstring problems; they're a nightmare.  But they didn't stop me raising nearly £6,000 at the London Marathon this year.  I ran with Ralph's brothers and uni friends, about five or six of us, all brought together for the day. 

I'd never been down to the marathon before, so I was blown away by the amount of people there.  The festive atmosphere made all our effort worthwhile.  At about mile 21, the hamstring tightness kicked in but we all ran our guts out - my time was 4:38. 

Now I'm looking forward to the Robin Hood Half. 

It was always going to be sad to go back to the event where Ralph died last year.  but I'll be joined again by a group of Ralph's close friends and family.  I hope to make it in under two hours, or even 1:50. 

My next goal is to complete all five marathon majors, starting with Paris next April. 

My passion and drive for all this comes from raising the profile of CRY.  It's the best way to prevent this kind of tragedy.  If one person reads this and decides to learn more, then we've achieved something. 

Ralph's parents have set up a memorial fund in his name.  Part of the money has gone to a guy we met in Africa, so that he can study for a physiotherapy degree of his own.

To donate, go to justgiving.com/inmemoryofralph.  For more info about CRY visit www.c-r-y.org.uk