"Go away go away GO AWAY," I yelled at the top of my voice. It was 7.30am on Saturday, a time when any self-respecting girl should be fast asleep.

"No, you've got to get up now," said Catherine sternly. "You'll miss Steptastic otherwise. Then you'll be sorry."

I severely doubted it. But I had to face facts. I was stuck in the North on a weekend euphemistically termed Fit'n'Fun in the Forest, where scores of exercise classes are laid on. In reality it was more like Masochism'n' Murder in the Mud. I cowered under the blanket. "I think I've got flu," I said.

"No you haven't."

"OK, I haven't, but I can't go to an exercise class at 8am. It's inhuman."

Protests squashed by Catherine and her sister Ann, I was whisked through not only Steptastic but also Aquamotion (in the pool), and Legs'n'Bums'n'Tums with a Pole (sadly, the poles had got lost somewhere on the M6, so we had the strange sensation of doing LBT with a pole without a pole. So to speak).

There was an hour's peace when I said I was off to find out about hiring mountain bikes (in reality skulking in the cafe bar with a much-needed bloody Mary) before the dynamic duo caught up again. "Hurry up! It's nearly time for Spinning [on an exercise bike, non-stop for an hour]. You haven't been hiding, have you?" Ann said threateningly.

"Only a little bit," I said. "I got depressed after the LBT instructor was fatter than me. If she's doing it all the time and is that size you can't really see the point."

For Fit'n'Fun was not (as I'd feared) an event peopled by women with Twiglet thighs, but it was infected with a strange aura of keenness. None of the three of us had been near a gym in months, yet there we were aiming for five to six classes a day. No sooner was I peeling myself off the ground after Spinning than I was being hustled towards Hot Hot Hot Salsa and Stretch 'n'Chi (don't ask). The gallant British spirit of having a go was everywhere, with faces set in rictus grins.

The three of us reeled back to our chalet. "I think it was wonderful," said Catherine. "I feel so alive."

"It just goes to show what a difference exercise can make," raved Ann.

"Stop hogging the Pringles, Cath," I said. "What's on the list for tomorrow?"

"Spinning again, followed by Karaoke Aerobics and Military Two Step," she said brightly.

"Great," we chorused gloomily.

"Oh God, look at the time," she said suddenly. "We'll miss our booking at the American diner if we don't scoot. Come on."