But apart from that, Wingham ‘superfish’ Allen Cornall is as healthy as you could be after a 12-hour endurance swim.

Allen, a year 12 student at Knox Grammar School in North Sydney, has raised more than $5000 for prostate cancer research after completing 614 laps of the Pymble Ladies College pool on Sunday.

The past state-level swimmer, who sat his final HSC exam last Wednesday, described the 30km swim as unlike anything he had ever done before.

“All along I knew I’d be able to do it,” the 18-year-old said.

“But there were parts where it got pretty hard.”

Allen’s achievement is the fruition of months of training, planning and drumming up support. His rigorous training regime involved two, three and four-hour non-stop swimming sessions to hone his body and his technique. Allen carbo-loaded with pasta, potatoes and meat in the week leading up to the event.

“I made sure had some baked beans before I started too,” he said.

“I had a fairly large supply of food on the day . Museli bars, bananas, sugar tablets, chicken sandwiches... there was enough there to keep me going.”

Allen hit the water at 6am on Sunday, only allowing himself to take three rest breaks of three minutes during the event. The rest of the time was spent churning up and down the pool.

“The first four hours were simple,” Allen said.

“After about six hours I started to feel the burn. By the eighth or tenth hour I was struggling big time.”

“I had a paramedic and my coach there with me the whole time. They pretty much saved me, giving me advice on my technique, rehydrating me and getting energy into me.”

A large crowd supported Allen’s efforts throughout the day. The numbers intensified as he neared the finish.

“I guess the adrenaline just kicked in towards the end,” Allen said.

“I think I was averaging a bit over one minute for each lap throughout the day, but I sped up a bit for the last 10 or so.