Whatever you have planned for the next two weekends, the chances are it won't be a patch on what this man has got lined up.

For Oxford University lecturer Hanno Nickau will be competing in not one, but two, Ironman triathlon races.

The gruelling events involve a 2.4-mile swim, a 112-mile cycle followed by a marathon run.

Your average' Ironman triathlete would usually take part in one or two a year and allow several weeks to recover from each one, but that's too easy for Mr Nickau, of Headington, Oxford.

Instead, he has decided to push himself to his limits and squeeze a season's worth of racing into one extremely testing week.

He has already completed one Ironman this year in Lanzarote, which is widely regarded as one of the toughest courses in the world, but next Sunday he will be in action in Zurich for Ironman Switzerland.

Just a week after crossing the finish line there, when most competitors would have their feet up and be enjoying some well-earned rest, 45-year-old Mr Nickau will be on the start line in Frankfurt for Ironman Germany.

He said: "Some people might think I'm mad, but I'm confident I can do it.

"I have plenty of experience of doing Ironman events, Lanzarote was my ninth one, but doing two back to back like this will be a new experience.

"It will tell me a lot about my training and my recovery rate and, of course, about my own mental strength.

"This is one of those challenges where you really test your limits.

"A team mate has told me I don't need to go and see a psychiatrist to find out if I'm mad, the fact I'm doing this just proves it."

Mr Nickau, chairman of the city's triathlon club, Oxford Tri, said this could be a good way to get into deca-Ironman racing, which involves a 24-mile swim, a 1,120-mile bike and a 262-mile run, the equivalent of 10 Ironman races non-stop. These events typically involve at least eight days of continuous swimming, cycling and running without sleep and can take years to recover from.

In 2004, he took part in events such as the Marathon of Britain, a six-day 175-mile race, and the Grand Union Canal Race, a 145-mile run from Birmingham to London.

He said: "Although I have done ultra-distance running in the past, I haven't ventured into the triathlon equivalent, but have been thinking about it."

His aim is to complete the two races in a combined time of 24 hours. He finished the Lanzarote course in 11 hours and 52 minutes.

In the week between the two races he will do little training to ensure he recovers as best he can and will have sports massage to speed up recovery time.

A number of Mr Nickau's team mates at Oxford Tri will also be competing at Ironman Switzerland. They include Simon Johnson, James McLaughlin, Matt Davis, Phil Richards and Emma Riggs.