It is a fact universally acknowledged that, as mums, we have the perfect excuse to avoid exercise and getting healthy. I mean, no one is busier than a mum, right? No one is more tired than a mum and anyway, don't we spend all day running around after the kids? I mean, if that's not cardio then I don't know what is. And OK, I may eat oven chips and fish fingers for dinner but it's only half a fish finger because, you know, I only ate the left overs so it doesn't count, right?  All of the above is true. Sort of. But, I've realised that exercise for me at 36 is not about keeping my ass in size 10 jeans (don't worry it was a long time since I was last in size 10 jeans ) but it's actually just about keeping going. Every morning, I'm stiff. My back is creaky, my achilles are tight and it takes me a cup of tea, a shower and stretch before I feel like my body isn't crumbling from underneath me.

I've convinced myself I'm not the only 36 year old feeling like this; that it comes to us all but actually, I'm lying to myself. The simple fact is that, until I was 26, I was active in competitive sport. Then I left competition and stuck to the gym, yoga and running. Since having babies, it's likely that I've had more smear tests than gym sessions and, honestly, I'm out of shape and frankly, a little unhealthy.

We're like grandfather clocks. We'll work perfectly forever provided we're properly looked after. We don't need much more than regular maintenance to keep the juices flowing. We don't need to be running marathons everyday but we do need to be able to race around with our kids, bend down a trillion times a day to pick up a cute but increasingly heavy baby that weighs approximately the same as two sacks of spuds and, you know, be able to get out of bed in the morning without creaking like a dodgy floorboard.

Exercise is no longer, for me, about attaining or maintaining my 26 year old body (but, sigh, wouldn't that be nice? If only I'd appreciated it when I had it...) No, it's about protecting my back, my joints, my muscles; it's about keeping my body working and fit for purpose, even if that purpose is lugging children around all day. Of course, it can't help to shed a few pounds, tone up a few wobbly bits, but essentially, the thing that motivates me the most when it comes to getting my arse of the sofa is thinking about NOT having to think about my body.

I don't want to wince and sigh as I stand up. I don't want to harrumph as heave myself out of a car. I want to look after my body enough so that I don't have to be conscious of every movement, tweak, twinge and, when you put it like that, when the goals are more possible and attainable than getting into jeans you bought at Tammy Girl, then it's easier to get motivated. If all we do is enough exercise to keep us working like a well-tuned grandfather clock, then that's pretty damn good.