When Karen Williamson crosses the finish line at the London Marathon, she will have completed a monumental 17 of the races in one year.
The 41-year-old started the gruelling challenge when she ran her first ever marathon last May and has so far taken on 13 races, including three ultra marathons of 62, 75 and 31 miles.
She has now been chosen from more than 400 applicants to run in London in April in aid of Diabetes UK.
When Mrs Williamson, of Whepstead, completes her goal, she will have run 1,580 miles and burnt 168,623 calories since starting her training last January.
She said: “Originally it was going to be 12 in 12 months. It’s a bit addictive and just before Christmas I had a look in the calendar and thought I’m going to round it up to 17.”
Mrs Williamson started running in 2010 when she began working from home for her husband Dave’s business.
She said: “Sitting at a desk you don’t realise how unfit you’re getting. The first run nearly killed me. It took me four or five weeks to run a mile consistently.”
In 2012, Mrs Williamson ran the Silverstone Half Marathon before taking on anothor four the following year.
Her next races will be the Portland Coastal on February 15, Cambridge Boundary on March 1 and Brighton on April 12.
She is running in London in aid of her chosen charity as her husband is Type 1 diabetic and has to raise £1,850. So far she has got £550 and has arranged a charity fishing match the week before London at The Nunnery Fishery, in Thetford.
Asked if she thought she could have done this when she first started running, Mrs Williamson said: “No, not at all. You start running one mile and then two miles and it’s just the progression. I don’t put any pressure on myself. I do a mixture of road and trail marathons and you see some beautiful scenery. It’s a whole new world that opens upto you. I just love it.”