phlebotomycourses: Senior athlete Eddie Brocklesby: my first world triathlon

It was an overwhelming experience. And one thing was on my mind: would my knees stand up to the run? But disaster struck even before we began ?

What a weekend of sport: the Great North Run, the London Duathlon and the World Tri championships in Hyde Park. My first World Olympic-distance tri was an overwhelming experience ? a vast international event on the home patch of the Serpentine running club and Serpentine swimming club. Could I do their support justice? Would my knees stand up to the run?

Sunday started disastrously. We had "racked" our bikes in the fenced-off secure pen called "transition" on Saturday afternoon, on rails with allotted numbers. Time would be allowed the following morning prior to our 8am race to take shoes, helmets and essential High5 Extreme drink into transition. But I got my timings wrong, and when I was in south London at 6.30am, I got a phone call from a friend: "Transition has just closed."

Would they let me in? Panic set in as I ran towards Hyde Park ? my usual buses were diverted because of tri-linked road closures. Thankfully, the volunteers and officials on duty accepted my "senior moment" excuse, and let me deposit my gear. Then, it was on down towards the Serpentine to haul myself into a skinny wetsuit. I was in one of those endless queues for the female loos when I got the best news ever ? the swim leg was being halved, to 750m; the water was too cold. Joy!

I met some of the others in my age group ? two phenomenal British athletes, Dorothy Wagstaff and Daphne Belt. Daphne is a true legend. She is 74 and has done 18 Ironmen. She was recovering from a recent injury, and we speculated whether her recovery would have been so swift if her bone and muscle strength had not been so good.

Having padded around for an hour in bare feet on the icy grass of Hyde Park, the Serpentine actually felt warm as we women of 60 and upwards sat in a long, regimental line on the pontoon, our feet dangling in the water, nervously awaiting the instruction to "enter the water". On cue, I dropped down, grabbed the pontoon and awaited the starting hooter. Scary. How I wish I had been a swimmer as a kid and was more water-confident.

The two-lap bike leg was absolutely fantastic: clear, blue skies, around Buckingham Palace, down Whitehall, past No 10 and out to Tower bridge. I was overtaken continuously by people going at speeds I can only dream about, albeit with posher, whooshing wheels. I only overtook two people and one of those was a delightfully enthusiastic guy in the 80-plus category.

Finally to the run ? had I done enough strength building to protect the knees? It was so, so hard, but pain free. With constant cries of, "Go, Eddie! Go, Edwina! Go, GB!", my kids and grandkids cheered me on, the temptation to stop and walk was resisted, just. I kept telling myself three laps was no big deal ? "visualise: it's only the monthly Serpentine Handicap". The final lap was fun ? albeit slow ?hands outstretched for irresistible high fives.

Then, at last, down the final straight, my friend Steve Trew commentating: I was fifth in 70-74 age group. Under the gantry, a TV camera in my face. And it was brilliant to learn that Dorothy had won our age group for Britain, in a fabulous time, 18 minutes earlier.

The BBC had filmed my training the previous Tuesday ? what fun that was. Incredible elitist name-dropping as the producers and camera man swapped stories with my coach Annie Emmerson. Yet here they were spending a whole day with an old woman! I even enjoyed swimming in Hampton Pool, before going into Bushy Park for the run shots. A large herd of deer watched bemused as Annie and I ran past. And on to Herne Hill velodrome. I love it. It was one of the sites of the 1948 Olympics and the home territory of the young Bradley Wiggins.

The film went out just before I settled down to watch the Jonathan Brownlee-Javier Gomez race so I missed it. But Facebook messages started to flood in. Finally, after just a few glasses of wine, I got to see it on iPlayer ? brilliant editing.

We must encourage more physical activity, and we are keen to roll out Silverfit sessions to other parks ? giving those seeking to get a bit more active the opportunity to wear the Silverfit T-shirt, do some exercise and, crucially, meet for refreshments afterwards. Please let me know any suggestions of a group already doing some regular exercise in a park near you ? could you create a sociable "silver Tuesday" event or use the web-based "meet-up" groups facility? We must get our ageing population doing more physical activity, looking and feeling younger-for-age. Last week, I went to speak to the cardiac support group at Guys Hospital, where members already appreciated the importance of exercise and strength training ? one fit-looking man in his 80s telling me that in contrast to friends who led sedentary lifestyles and have all died, his fitness and exercise is key to his survival. I'll ask him to tell his Inspire story on our Silverfit website.

What next for me? I'll have two or three weeks' rest from running and strenuous biking before planning for 2014. I thought I might have a go at kayaking ? I watch them come from Cremorne Riverside Centre down the Thames. But 6.45am does look a bit early. Maybe there is scope for Silverfit kayaking sessions? Age is just a number when you are having fun.