An Irish ultra runner has successfully completed seven marathons on seven continents in less than five days.

Galway man Richard Donovan broke his own record by completing his final run in Sydney after seven marathons in four days, 22 hours and three minutes.

The 45-year-old admitted sleep deprivation, running, and travelling through different time zones and temperatures took its toll on his body.

"I was absolutely wrecked. I wasn't even able to keep down water," he said.

"We came to desperate measures in Sydney and I chanced a beer.''

He said he had a bottle of beer during the race for some carbs and one at the end of it.

"It was the first time something stayed down in days."

The father-of-one began his epic quest in the extremes of Antarctica last Wednesday, running the first 26-mile leg in -20C at the Russian Novo science base.

He has since ran 183 miles and flown 27,055 miles.

His round-the-world marathon took him from Antarctica to Cape Town, to Sao Paulo, Orlando, London, Hong Kong and finally Sydney.

He did the endurance challenge on a shoestring budget out of his own pocket to raise awareness of the humanitarian crisis in the Horn of Africa.

Mr Donovan, who was inspired to attempt the challenge in 2009 after the failed bid by British explorer Ranulph Fiennes, said he was not on any special diet, was flying economy on his own and was bringing whatever he could fit in one bag.

Before setting off, he said sleep deprivation and massive temperature fluctuations would be his biggest challenge.

Money raised through online donations will go to Irish aid agency Goal, one of the few charities working in the Horn of Africa.