Eavesjogging: Half the fun of running is listening in to other people's conversations

Running isn't only about fitness and beating stress, says Philip Norman

Others may gripe about this past non-summer with its rare dividends of sunshine far outweighed by rain squalls, mini-tornadoes and skies like dirty dishcloths. But for me, those were perfect dog days – or, rather, jog-days.

I've been jogging (or, as I prefer to say, running) for something like 30 years, a couple of miles two or three times each week. Medical science has lately begun to question the benefits, especially as one gets older, but I couldn't be without it. Running, for me, long ago ceased to be a form of exertion or even conscious effort. Once I get out there, my legs take over and my mind gives a deep sigh of relief; indeed, there's only one other pastime that relaxes me more.

It has also been an incalculable help to my writing career. Often when I set off, around midday, I'll be grey and despondent after a morning futilely grappling with some problem at my desk. In the fresh air, with blood pumping all round my body instead of just short-circuiting to clog my brain, I usually resolve the difficulty within minutes.

I'm lucky to live near one of those tracts of public land with which earlier generations provided this country so bountifully, and which no one has yet managed to steal. Plodding along at a steady 5 mph, I feel as close to nature as David Attenborough, listening to the lullabye coo of f pigeons, wishing every magpie a polite "Good afternoon, Mr Magpie" (why does one have to do that?), watching a hawk hang motionless on an updraught or catching the strangely mechanical rattle of a woodpecker.

Mainly, however, it's not birds that I watch. Most runners play music to keep themselves going, but my fellow humans entertain me every step of the way. At this empty hour, they're mainly people walking dogs, in every size and colour, from chihuahua to Harlequin Great Dane (patterned like a Dalmatian but built on the lines of a Shetland pony).

It's true what they say: dog-owners do end up looking like their pets. I always wish they could feel like them, too, for nothing matches the bounding. curveting, foraging joy of a dog during these precious moments of freedom, while the owners seem sunk in gloom. Possibly that has something to do with the scoops and small plastic bags they're usually carrying

Then there are also the professional dog-walkers, somehow holding on to 10 or more straining leads. How do they keep track of all their charges, the Jaspers, Aslans, Roxies and Mordreds? Occasionally, two dog-walkers will stop for a chat, creating a yapping, squabbling canine traffic-jam as they discuss Milo's recent tumour-operation, Jordan's ingrowing toenail or Zeus's incurable habit of chasing children's balls and chewing them.

Now and again I meet another runner or, more likely, one will come up behind, competitively intent on passing me, then often annoyingly slowing right down to a snail's pace. There's little cameraderie among runners; in fact, I detest the whole species with their comic-sloganed T-shirts, revolting Lycra shorts like President Sarkozy's and iPods fizzing faintly with music I know I'd hate. It's why, in all these years, I've never been tempted to enter a marathon. The thought of being among thousands of runners, some of them dressed up as teapots or Ronald McDonald, is too horrible.

An increasingly common sight are long lines of young mothers power-walking with baby-buggies like a wagon-train, escorted by a female team-leader in a tracksuit barking out directions and encouragement: "Now ladies, get ready for a 90-degree turn straight up the hill... step out nice and lively now ... keep the rhythm going there, Helen ... Oh, nice arm-movements, Sophie!"

Best of all are the scraps of conversation from walkers I overtake as they talk to companions or into mobiles. For no one seems to notice runners or feel the need to lapse into discreet silence as we flap-flop past. Alan Bennett has said how many of the funniest lines in his plays come straight from real-life exchanges he's overheard on buses. I have my own collection, gathered in the course of my runs and waiting to go into their own Bennett-esque drama. An eavesdropping jogger: does that make me an eavesjogger?

Mobile phone soliloquies tend to produce little of interest beyond "I'm out for a walk" or "Could you e-mail the new business plan to me by Monday?" But the interactive dialogue – usually a duologue – can be riveting, all the more so for lacking any resolution or punch-line. For a couple of seconds, I peer deep into the lives of others, then leave them and their problems and preoccupations in my wake.

There are, for instance, the people discussing some troublesome spouse or child or friend or work colleague with what HG Wells called 'gloomy relish': "I've had it up to here... You know what I've had to put up with. But that's it. No more..."

Then there are the pairs of young lovers at that magical early stage where she listens to everything he says with wide-eyed fascination. The eavesjogger has seen that enchanted look bestowed on a swain as he was saying "I've just set up a consultancy for a rubber-derivatives company." And on another one while he explained in exhaustive detail the fermentation process of cider.

Then there are the mothers with toddlers, valiantly trying to keep up a conversation of interest to a three- or four-year-old while secretly wondering whatever happened to their lives:

"No, Ethan, I don't know why superglue doesn't go hard while it's in the tube."

"I promise you, Atlanta, the next dandelion we see has got your name on it..."

"Yes, Dylan ... more dog-poo".

And one that made my blood run cold:

"I'm sorry, Jasmine... you've missed your window for a hug."

Or how about this, from two teenage boys, striding along in the pelting rain – without jackets, naturally?

"Your Grandad flies all around the world, doesn't he?"

"My Dad, yes."

"And he was the President, right?"

"Prime Minister actually."

"That is so cool."

One thing eavesjogging has taught me is never to judge by appearances. The other week I passed two down-and-outs, as I thought, talking about nothing more elevated than their next bottle of cider.

"I've just seen my favourite member of Cream," said one.

"Ginger Baker?" his companion asked.

"No, Eric ... Eric..."

The most memorable of these alfresco soundbites came one day as I passed a tough-looking young woman loudly holding forth to a female friend. However, the subject wasn't pop music, boyfriends or trash TV, as I expected in my prejudice, but classical mythology.

"Leviathan," she was saying. "Colossus... whatever..."

Memo to Alan Bennett: buy yourself some trainers and a headband. You could save a fortune in bus fares.