LONDON (AFP) - Cyclists and rowers can stay in top shape in their personal gyms even during the coronavirus shutdown but Olympic swimming champion Adam Peaty has to make do with no pool.

Britain's Peaty, an eight-gold world champion, would have been preparing for the Olympic Games in Tokyo had Covid-19 not forced a postponement.

It has forced the 25-year-old to change his workout schedule and diet.

"Swimming is one of those things where you can't really train unless you're in the water and unfortunately we're not going to be in the water for probably another three weeks, minimum," he told BBC Radio.

"It's really hard for a non-swimmer to understand the connection you have with the water. They say a day out (of) the water is two days to get back so it just depends on how long the lockdown lasts and when we can get back.

"(I'm doing) gym in the house then a lot of running, a lot of cycling, but mainly just staying on top of the core."

Peaty's routine at the moment is far removed from his usual 10,000 metres in the pool on top of gym work, which means a change in his eating habits, too.

"The best thing we can do is stay on top of our diet, because when you're in isolation all you want to do is eat," he said.

"I'm doing a lot of intermittent fasting until 2pm... Just keeps the fat away and that's the biggest battle we have.

"When I'm in full training... you're probably looking at (burning) 4,500 calories, now I'm probably trying to stay around 2,500."

Peaty already has his sights set on peaking for the Olympics next year.

"I've been waiting four years for this moment and it hasn't come," he said. "But there's way bigger things in the world at the moment.

"Hopefully if we can beat this thing and come together. I think the Olympics will be a great celebration."