Dom Joly: Where exactly is the fun in a fun-run?

Weird World of Sport: Every runner or jogger that I see has the same unhappy look etched onto their face

I was getting on to a plane from Heathrow bound for Milan and it seemed to be packed with very gaunt, tired-looking Italian women in tracksuits. For a while I couldn't work it out. Was this the return leg of a particularly strenuous weekend Anglo-Italian yoga break in the Lake District? Maybe it was just an away-day flight taking members of the "very thin and ill-looking Italian club" for a trip around London. I was very curious so I did my usual and eavesdropped.

My Italian is far from fluent but I quickly overheard and understood enough to solve the mystery. All these sickly looking women were returning from the New York Marathon. Despite it having been three days since the event took place, they still looked completely knackered. Now I was hardly surprised by this – after all they'd had to run more than 26 miles while facing the unique "friendliness" of the New York populace. That would be tough work for anyone. My first thought, and it's one that I often vocalise when I see somebody running is, "What are you running from?" There is just a look of basic unhappiness etched onto the face of every runner and jogger that passes me, leaving an unpleasant slipstream of BO. These are just people taking a jog around the park.

The idea that they get on planes and fly halfway round the world to run is ludicrous. I always understood that the main point of running was to keep you healthy and fit. The specimens on my plane might very well be fit but they seemed far from healthy.

Their pale, bony faces sat staring vacantly into the middle-distance. When the stewards wheeled past them they all asked for a small bottle of water and some nuts. Then they sat, chomping vacantly and taking occasional half-hearted swigs on their water bottles. And yet we love marathons here in the UK.

Every year, more and more people decide that they're going to put themselves through one. Most of the time it's for charity – which is laudable although there must be easier ways of earning dosh. For some, simply running the distance is not enough – oh no, they want to do it while tied to someone else, or dressed as a boa constrictor, or while cooking the world's largest omelette.

I find the whole thing painful to watch, let alone take part in. There's something about sponsored "fun" runs which makes me feel like lying down and watching television. Last year, I was approached by a charity that wanted me to get in training for the London Marathon. They blackmailed me with the worthy causes that I would raise money for and flattered me as to how fit I was going to get. For a moment I wavered.

I rang a friend who had once run a marathon. I asked him tell me a little about what it was like. He wailed down the phone. He'd run the New York Marathon. He thought it would be fun – a weekend in the Big Apple, shopping, a night out then the race and back to Blighty as a conquering hero. When he put it like that it didn't sound too bad – but then he got down to details. He told me of his regret at not having put enough Vaseline on his testicles – the skin had nearly been completely worn away. He tried to express the pain of this unspeakable affliction but it brought him to tears.

Then he described the intense bout of projectile vomiting that he went through once he'd crossed the finish line. He described it as like "trying to turn your entire body inside out". He'd been given one of those spooky silver blankets after the vomiting episode and he'd staggered off down a street only to pass out halfway down. He woke up in a New York hospital with his testicles bandaged up.

He couldn't get out of bed or even use the telephone. As he relived his ordeal, I could hear the horror in his voice. He was allowed to fly back three days later and has never run since. I rang the charity back and thanked them profusely for their interest in me and for their kind offer. "Having thought long and hard about it" however, I had decided that this one was really not for me. I promised to give serious thought to their croquet tournament. Sometimes you've just got to know your limits.

Boris all rage in cage?

Haye versus Valuev – we need more of this sort of thing. How about Willie Carson cage-fighting Boris Johnson? Come on... you know you'd watch.