If you managed to do that 20 times without a single stop, you would have climbed the equivalent of Mount Everest - all 8848 metres of elevation worth.

Alani Cockshutt and Monty Moore became two of only 9000 people in the world to scale Everest on bike app Zwift on Sunday.

In doing so, they became the youngest-ever duo to do so after successfully riding 245 kilometres on Zwift - a virtual training application used for cycling and running.

Throw in more than 10,000 metres of elevation in a little over 12 hours and the funds raised as a result for the Starlight Foundation will be the most satisfying part.

That's after their legs recover.

Alani's mother Mel - who has done numerous Ironman events - called it quits after 220 kilometres, allowing the teenagers to push on for another lap and three-quarters.

"It was harder than Ironman; just the elevation ... you were climbing and climbing and climbing so you even started to dread having to go back up the mountain on the way down," she said.

"It was a really crazy thing; but the kids did 10,000 metres so they had to do one and a bit more climbs."

Moore's longest elevated climb before Sunday was no more than 1000 metres.

"It was so crazy, but we rode every lap side by side and within 10 seconds of each other," he said.

The trio broke their 12-hour day up by celebrating milestones along the way.

Mount Kosciuszko was the first at 2200 metres, then came Mount Fuji (3776 metres), followed by Mount Kilimanjaro (5895 metres) and then Everest Base Camp (5500 metres).

And then it was time to tackle the summit.

"I was in a really good head space, but we only really had one bad lap each and that came down to technical issues," Alani said.

"I think over 100 people on the day joined online and climbed with us or visited and said g'day."

Their goal was to raise $10,000 and as of July 14 they had raised $12,500 with mum Melinda and Bennett Powell also raising a further $5000 for their Tour de Cure efforts.

"We wouldn't have been able to do it without everyone's support because the donations just blow you away," Cockshutt said.

"It's a lonely time for people going through cancer during COVID at the moment so having people like Captain Starlight being able to still see these people is great.

"The ride was definitely one of my craziest ideas."

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