‘It’s not unlike that scene from “Rocky” except that I still can’t lift anything heavier than a can of baked beans’

Things I am allergic to: people who believe in star signs and think nothing of starting a conversation with: “Hi, my name’s Lucy. I’m a Sagittarius”; rodents (apart from miniature hamsters, which are not in fact rodents but small, breathing, brown balls of cotton wool); and people who go to the gym.

All my life, I have avoided any sort of exercise. I don’t enjoy sweating and I think people who show off about having just done 20 press-ups are pretty weird.

I’ve always been amazed by the eerie pull of a large white room housing rows of ugly, grinding machines and the prospect of running absolutely nowhere. And if that isn’t appalling enough, the very idea that you have to pay someone a grand a year for the privilege?

I don’t like moving, full stop (if the remote control hadn’t been invented I’d still be watching the same channel – CBeebies, if you’re asking), although I sort of get that walking in a cornfield might not be unpleasant. I suppose a swim isn’t a totally useless way to spend an hour, and people who love skiing (although I don’t talk to these individuals either; they’re like the star sign believers, only in fleece jackets) say that zooming down a mountain is brilliant fun and that their thighs and bottoms are firmer for it.

But here’s the thing – it all feels like too much effort for very little upside. So you set an alarm for six in the morning so that you can sprint to the gym, pretend to kayak for an hour, shower, dry your hair and then get to the office in time for a low-fat muffin. For what, exactly? For a slightly more sightly calf or maybe half an inch off your upper arm? Jesus, who notices these things? And if it’s a lover you’re after, and they do care about the size of your arse, then just tell them to stick something long and pointy up theirs.

These were my beliefs a fortnight ago. Then, a girlfriend and I fell out because she decided to run round Primrose Hill instead of eating breakfast with me. I was stunned by this action. We love each other, we’ve known each other for ever, we’ve spent the past 15 years eating the same snacks (pancakes for her, waffles for me) in the same little cafe – and then the world stopped spinning on its axis and she decided she needed to “work out”. We met up after she had finished her run and she sat there, all glowy and smiley, and she ate wholemeal toast. I know. Shocking.

Anyway, I did something ridiculous. I signed up for a six-week gym course with a man they call the Body Doctor. Of course, I turned up livid. One: I assumed he would tell me that I’d have to perspire (he did and I did). Two: I predicted that tall, thin gym-savvy people would grunt on nearby machines while I fell off a running machine (they did and I did).

So it wasn’t looking good. The Body Doctor (I simply have to use capital letters – you would understand if you met him) is the meanest man on earth. He yells at me: “If you’re eating a pint of Ben and Jerry’s every night just because you’ve given up the fags, you’re doing you and me no favours, so go home!” And: “I don’t care if you don’t like pretending you’re walking up the stairs. Just do it or stop wasting my time!” He has minions, body nurses if you like – Rob (spiky hair, sounds exactly like Johnny Vaughan), Becky (blonde, goes out with a plumber) and Wala (uses the word “quality” a lot) – and I hate all of them.

They make me get out of breath (this makes my head itchy) and then I have to lift stuff. Twenty-five times in a row. They use words I don’t understand. “Come on, it’s time for abs!” does not in fact mean that an ex-member of the boy band Five has arrived to perform a mini-concert for us. It means I have to lie down on the floor and do actual sit-ups. It’s not unlike that scene from Rocky except I still can’t lift anything heavier than a can of baked beans and I want to make a meringue whenever I see a raw egg.

Still (and this is the really weird bit) even though I loathe myself for admitting this, I feel better. Much better.

I can now run for a bus (if I were to take one, obviously), and I don’t mind putting my hand on my stomach (only lying down, mind; sitting up, it’s still in all kinds of trouble). I’m even looking forward to seeing Rob and Becky and Wala, and I’ve told my friend Sara that I’ll run round the park with her next Saturday, before we share a fruit plate.

My husband is horrified, of course. He’s never been big on change and he thinks that if I can decide that lifting weights is a perfectly reasonable thing to do at 9am on a Tuesday, then I might have sex with the postman (he’s devilishly handsome, by the way) and run off to Dorset with him.

I have tried to quell his fears. Of course I won’t run off with another man. That’s just not me. What does he think I am? A Scorpio?