I can swim 1500 metres without much fuss. I didn’t used to be able to do this. Not so long ago swimming 15 metres would have been a struggle. But now I can do that 100 times over. I’m trying to remind myself this. Thinking of it as half an hour splashing up and down the pool makes 1500 metres seem less intimidating.

1500 metres is just 100 short of a mile. A mile seems quite far. A long way to swim, even further to climb. Almost a mile, straight up. How high would that be? The Shard is 308 metres high. I went up there one Christmas and it looked a long way down. I can see the top of The Shard from my front door. Five times up The Shard seems a long way to climb.

It’s just under two weeks until I take part in the Eco Trail Paris. I’ll be lining up for the 80km event. The course runs from the outskirts of Paris to finish at the Eiffel Tower. It’s made up of 95% trail. And it covers 1500m of climbing. It’s a number I’ve been a bit preoccupied with.

Last year I was fixated on another number, the 1200 metres of climb on the Ironman UK bike course. It was a course I didn’t finish. Here’s hoping I’m better at running up hills than I am cycling.

I’m a fan of race-specific training, so at the weekend I headed off on a route that best replicated the course in Paris. I set off from Finsbury Park to Hyde Park, via every bit of north London off-road terrain I could find. I ran along the Parkland Walk, through Queens Wood and Highgate Woods before running through Hampstead Heath.

At Hampstead Heath I could see the city ahead of me, including The Shard. From the top of Parliament Hill, it didn’t look so big.

I carried on to Hyde Park where I met Laura Stewart and 12 other women who’d gathered for a run to celebrate International Women’s Day. I forgot about running up hills and talked about running for the fun of it.

Last year in Bolton I learned that it’s OK not to finish a race. That you can still turn up, have a go and, if you you fall short, it’s still possible to have a good time. Who knows what will happen in Paris. As long as I have good time, it doesn’t really matter where I stop running.