I've got a new obsession. It's not a new make-up range, or even the latest spa treatment; it's more of a toy. Not since the rampant rabbit hit the shelves has a battery-powered device caused so much excitement in my life, or around the office water cooler, for that matter. The object of my affections is my pedometer, and it's driving me crazy, in a first love sort of way. I am a woman obsessed. I can't get it out of my mind. I feel as if I'm having an illicit affair - neither of us is going to leave our partners, but it's OK because it's just a bit of fun and I'm sure it won't last.

Pedometers have been an underground fitness craze for a while, but they are about to be everywhere. A couple of weeks ago, fitness guru Joanna Hall wrote about them in the Wellbeing pages of Weekend in relation to her mission to get a group of MPs to walk 10,000 steps per day, and now Kellogg's has started giving them away with Special K (along with the obligatory £3.99 plus two tokens), which means it will only be a matter of time before every other waistband has a small, red, pager-like contraption attached to it.

The basic idea is that, for optimum health, you need to clock up at least 10,000 steps per day. But what the leaflet doesn't tell you is quite how addictive it becomes. I've never been much of a walker, I favour style over comfort when it comes to footwear and, being on the petite side of things, I seldom wear flat shoes. Taxis are my financial downfall and buses are my usual mode of transport (evens things out, you see), with the occasional tube thrown in whenever I feel the urge to be groped by strangers.

But now I walk all over the place. I take the stairs instead of the lift. I even do that cliché of getting off the bus a couple of stops early and walking the rest of the way. In the process, I've lost a few pounds, my legs look trimmer and feel firmer, and all that walking really does make me feel great - though, of course, it's hard to say whether that's down to the health benefits or the fact that I will compete with anything, even if it's an inanimate object.