Most of his toenails have disappeared, there are blisters all over the bottom of both feet and there's no skin on at least four of his toes.

With feet that ''would make most people vomit'', Fryer said it was all worthwhile, given he had returned to his Weston home with the unofficial title of 48-hour running world champion.

In an event most people would baulk at, Fryer ran 433.69km in the Surgeres 48-hour ultra-marathon in France last Sunday.

It was the first time the 47-year-old had broken the 400km barrier and when he flew back to Canberra yesterday with 40 hours of travel under his belt, his body was shutting down.

''There's at least three or four toes where the whole skin and nails have come off and they look like they're all kind of gangrene, but they're okay,'' Fryer said.

''If I showed you some pictures of [my feet], I'm sure it would make most people vomit. It's hard yakka, I'm a basket case right now, to put it mildly.

''But I exceeded my expectations and I'm over the moon so it's worth all the pain and fatigue.

''My body has gone into shut down, I've lost weight even though I'm eating like a pig so I'm not too keen to do one again any time soon.''

For more, pick up a copy of today's Canberra Times