I'm running the Berlin Marathon for my parents - and for many others like them. During the past few years, both have been diagnosed with Alzheimer's disease. Whilst they still live semi-independently, this progressive disease is affecting their memory and many other aspects of their lives. As a consequence, they need more and more support.

I'm proud to be supporting the Alzheimer’s Society, who are a fantastic source of support and advice to me and my family. They are working towards a world where dementia no longer devastates lives. They do this by giving help to those living with dementia today and by providing hope for the future by campaigning to make dementia the priority it should be and funding ground-breaking research.

I've been a runner since I was a teenager in the 1980s, inspired by the battles between Steve Ovett, Sebastian Coe and Steve Cram. Mum and dad supported me: standing in the rain and shouting encouragement at school cross-country races, and taking me to track meetings. Many years later, when I had taken up marathon running, they came to watch me complete the Paris Marathon in 2013. Berlin will be my 12th marathon. I'm not as quick as I used to be, and injuries are more common - especially in the last 18 months. But this one will be particularly special because this cause is so important to our family. I'll do my best to get to the finish in one piece!

Please consider supporting me and the Alzheimer's Society. Every donation, however small, will make a difference. Thanks.