Fight for Sight researcher Matteo Carandini reflects upon the lessons learnt during his first marathon

It's been three months since the London Marathon, my waistline is growing back to normal, and I am pondering when I will run my next one. Though I had run a few half-marathons before, this was my first full marathon. It turned out to be one of the most challenging and rewarding things I have ever done in my life, and I was extremely proud of running it for Fight for Sight, a charity that I support in every possible way.

As most people know (but I didn't), a full marathon is completely different from a half-marathon. At 21 km (13 miles), a half-marathon is just a long run; you train for it, pace yourself appropriately, and that's it. A marathon, instead, can enter a bizarre scenario, called "hitting the wall". This happens when your body runs out of carbohydrates. If you hit this wall (and I did, in the last few km), you feel completely spent and you beg your legs to please make one more step. It is unpleasant in such a strange way that it is actually interesting (and I would do it again, because now I know I can survive it!).

So, as a colleague explained to me after the marathon (why didn't I ask him beforehand?), the point of a marathon is to pace the first 35 km in such a way that you can actually run the next 7 km. I had little idea of this: my longest training run was about 30 km, and it gave me only a faint idea of what a real marathon is.

So, when I decide to train for my next marathon, I will do a couple of things differently: put in longer runs, and be less obsessed with heart rate. I trained for this one right after buying a running watch, and with the watch came a training program entirely based on heart rate zones. By keeping your heart rate low, these programs hope to turn you into one of those athletes who blaze through a marathon with barely an extra heart beat. But I am a middle aged scientist, not an athlete, and at that low heart rates I can only run very slowly. This is good for preventing injury but it does not build up enough mileage.

Anyway, why does one enjoy all this training, to culminate in this ridiculously long run? I am not sure, but I sure did enjoy it. I was proud to wear Fight for Sight's green shirt (as ever: I wear it in all my runs). I ran all the way. I enjoyed most of it during the event, and even though I hit the wall, I am so happy I did this. My time was very slow (4:55) but I ran all the way. I think I am ready for the next one.

Click here to find out how you can run a marathon for Fight for Sight.