Three months into my gym membership and I’ve dropped out again, ignoring the urgent messages left on my mobile to get in touch with the personal trainer.

If I had a pound weight for every gym membership I’ve let lapse, I could build my own mirrored room with intimidating equipment and smelly rubber mats and a spacehopper-sized ball that everybody describes as “amazingly effective” and then promptly falls off.

But still, I have a problem. If I don’t take exercise – that loathsome, punishing activity that makes my body feel like a cumbersome, heavy suitcase that I have to drag behind me – I will, according to informed medical opinion, regret it for the rest of my short life.

My bones will crumble, if my heart doesn’t pack in first.

In a decade or so, I will not be able to tackle the front door step, let alone a flight of stairs. Run for a bus? More like sit around waiting for an ambulance.

I have no quarrel with this argument. Use it or lose it makes sense. It’s just that, for some people, and I’m one of them, using it to do much more than pop down the garden or maybe up the shop to get a paper is not a particularly pleasant experience.

Advocates of exercise talk about the buzzes and highs. That doesn’t happen to me.

While I can feel euphoric after a couple of glasses of wine or a bar of chocolate or even post-operative diamorphine, when it comes to producing endorphins following a run up a hill, nothing happens.

Well, nothing except pain in my thighs and calves, and an uncomfortable sensation as my lungs try to adjust to full expansion and contraction, instead of their normal default state of flapping about.

But still, exercise I must. Which is why I’ve come up with the car-free plan. From last week, if I want to go anywhere within a three mile radius, I walk. Need some groceries? It’s only an hour’s walk to Sainsbury’s.

I stride off quite comfortably, and get there well within the 60 minutes, for it is downhill all the way. I buy a few bits – joining the fast-track basket queue because I can’t carry much without the car – and, feeling quite pleased with my progress, start to walk back.

The stride turns into a plod as the gradient increases (and as the weight of the bags increases too, or so it seems), and after an hour I am unaccountably still half a mile from home, telling my legs to just keep on putting themselves in front of each other and making huge efforts to breathe normally so passing motorists don’t feel obliged to pull over and check if I want a lift to A & E.

And so it continues. If I can’t come up with a reason for having to walk for an hour and a half every day, I get my husband to drive me a couple of miles from the house, turn me out of the car to walk home without any loose change so I’m not able to catch a bus back.

I feel like Hansel or Gretel at times, especially when the route is unfamiliar, but in order to stave off the boredom – another unsavoury feature of exercise. I also need to find my way back home.

One night I’ve taken a bit longer than usual to return, and my husband’s looking a bit concerned when I get in.

It’s dark now, as I foolishly took a public footpath that I thought would cut 20 minutes off my trip but actually led me astray and into a large wood which was tricky to negotiate without sat-nav or Google Earth.

“Sit down and have a cup of tea,” he says, opening the fridge. I can see that there’s a big empty space where the milk should be.

He looks at me. My thighs are almost crying. My T shirt is wet with sweat. My head says I should go over to the shop. But my heart speaks.

“I’ll have it black, thanks,” I say.