Double Olympic gold medallist Rebecca Adlington has revealed she could quit the 800m freestyle before London 2012.

Adlington, who on Sunday starts her bid for double gold at the World Swimming Championships in Rome, is the world record holder over the distance after smashing the previous best in Beijing last August, just five days after winning the 400m freestyle crown.

But she warned her body might not be up to the rigours of the event for an Olympic defence on home soil in 2012. "In three years' time, the chances are my body could be completely different so I have to be realistic and also the 800m freestyle might not even be at the Olympics as an event," said Adlington.

"So I might change and take up the 200m freestyle instead. But I'm not about to do anything crazy like take up a different stroke. I'm rubbish at other strokes and that would be an utter disaster."

Adlington is relishing the chance to take on the world's best for the first time since Beijing. She's in good form, having clocked the third fastest swim of all time in the 800m - an event she describes as being "like being hit by a ten-tonne brick" - at last month's National trials, edging British rival Jo Jackson to second place in the process.

And Adlington said she was relishing the opportunity of a British one-two in the Italian capital.

"It's thanks to Jo that I swum such a quick time in Glasgow," she added of her close friend. "In fact, without her I'd be a lesser athlete so a one-two in the World Championships would be fantastic."

Life since Beijing has been an "utter whirlwind" for Adlington after she became a household name overnight. Following the Games, she took five weeks out from the pool and fell from the peak of her powers to becoming "as unfit as I'd ever been".

She said: "When I landed back in the water for the first training session, it was like 'yes I'm back' but it all seemed really alien.

"Anyway, all the Olympic attention has passed now and it's not like I'm Britney or Madonna, I'm just Becky Adlington, and if I needed bringing back down to earth at all, there's nothing like waking up at 5am to train for the World Championships to do that to you."