John Kelly breaks record for scaling all 214 Wainwright fells in the Lake District

A former World of Warcraft fanatic who was “good but not great” at running at school has broken the record for scaling all 214 Wainwright fells in the Lake District.

Many walkers set themselves a lifetime challenge of summiting every peak in Alfred Wainwright’s seven-volume Pictorial Guide to the Lakeland Fells. John Kelly, a 37-year-old data scientist from Tennessee in the US, completed them all in five days, 12 hours and 14 minutes.

He slept between one and 2.5 hours a night, taking micro-naps in a camper van at 25 meeting points along the way. “I’m told I napped between bites of pizza at one point,” he told the Guardian.

He attempted to eat 300 calories every hour, but said it was impossible to replace the energy he burned each day.

The father of four smashed the record set last year by Sabrina Verjee – who supported him in this attempt – by about 11 hours. He was also assisted by Nicky Spinks, a breast cancer survivor who has broken numerous fell running records; evidence, he says “of just how supportive and strong the ultrarunning community is”.

The 320-mile (515km) challenge, which includes England’s highest mountain, Scafell Pike, involves a total ascent of 36,000m (118,000ft).

Kelly had to abort his first attempt at the challenge last July after suffering with heat and foot problems.

His children – five-year-old twins, an 8-year-old and a 19-month-old – joined him for the last leg of the run on Saturday. “It was kind of funny because I had to ask my eight-year-old to slow down because he ran off so fast,” said Kelly.

He insisted he was never a brilliant athlete growing up. “I ran cross-country and did athletics at school, but I wasn’t the top person on the team. I was good, but not great; I could do 5km in around 17 minutes.”

His training for ultrarunning mostly takes place on his daily commute, running 10km to and from his office in Bristol, where he is the tech co-founder at Envelop Risk Analytics.

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On his website, where he calls himself the Random Forest Runner, Kelly describes his previous passions, saying he “used to be a pretty serious water-skier. And World of Warcraft player. But now just family, work, and running.”

Asked by the Guardian why he runs, Kelly said: “Facing these types of challenges that put us at our absolute limits really strips us down to who we are: what our strengths are, what our weaknesses are. We learn how to leverage those, how to mitigate them. And I get to do this while doing an activity I love, which is being out in the mountains and exploring as many of them as possible in the time I have.”

Kelly is a winner of the Barkley Marathons, often described as the world’s toughest endurance race, which sees competitors try to run 100 miles within 60 hours in the Tennessee wilderness.

He also holds the record for completing all 258 miles of the Pennine Way, finishing in 58 hours and 4 minutes last May. In addition, he has completed the Grand Round (the Paddy Buckley Round in Wales, the Bob Graham Round in the Lake District, and the Ramsay Round in the Highlands) continuously, linking them by bike.

He and his family are returning to the US at the end of the month, and his next challenge is the 100-mile Hardrock race in Colorado.