She launched her latest record attempt at 6am today and aims to complete 500 gruelling kilometres by Sunday afternoon - the equivalent of about 12 marathons.
The former jockey won't sleep during that time and expects to lose more than 3 per cent of her body weight.
She is aiming to cover 332 laps of the Domain in about 85 hours in order to beat US runner Pam Reed's record, who ran 486km in 2005 in just over 80 hours.
So what's the attraction? Not running apparently.
"There's ultra runners who go out and train huge miles - that's not me.
"I like the mental aspect to it. I'm not a fast runner, I'm never going to be a fast runner. It's the beating my own mind that I like. Thinking you can't do something then you go out and do it.''
Ms Allan spoke to APNZ about 1.30pm, after running for just over seven hours and completing 63km.
She vowed this would be her last attempt - the previous year's effort ending in "failure'' after 85 hours without sleep and 376 painful kilometres completed.
She had suffered severe blisters and was haunted by "scary'' hallucinations on the final day between midnight and 5am.
But she is motivated by the pain she endured recovering from her compound fracture.
"I swore then, `I'm never going to take for granted the ability to get out of bed and walk'.''
Ms Allan is urging Auckland runners to join her at the Domain for a few laps, to help buoy her spirits during the punishing record attempt.
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