I’ve long been hooked on pushing my own personal boundaries, excited and strangely curious at how I can use my mind to will my body through extraordinary physical barriers. It started nine years ago, when I entered a horse race at Goodwood for charity. My fitness reached a level I’d never attained before, thanks to twice-weekly sessions with a sports scientist and honing my skills on the racecourse several times a week.

I then turned my attention to sailing. I began offshore yacht racing in 2011 and a year later raced across the North Atlantic, a storm-ridden, hellish journey that took 15 days and during which I feared for my life on more than one occasion. There followed ski mountaineering races, cycling challenges and training for an ironman that I sadly never managed to start due to injury.

“My cold and tired hip flexors, quads and calves screamed with every step to the point I could barely pick up my feet…”

And so here I was on the start line of a marathon, three days into my first multi-day endurance event, which was far tougher than anything I’d ever experienced before. After yet another night of sleep broken by piercing chill, we’d risen at 5am: excitement in our voices as the camp stirred into life in semi-darkness. There was sadness that the adventure was nearly over, but excitement that a warm bed and hot shower would be waiting for us at the end, rather than another wet wipe wash.

I’d prepared my race pack the night before, having learnt on day one that trying to fill water containers and mix in hydration powder, measure out my home-made trail mix and count out energy gels is hard when delirious with sleep deprivation, fatigue and cold. I shuffled around camp mixing warm water with my expedition ration breakfast of porridge and hot chocolate, my cold and tired hip flexors, quads and calves screamed with every step to the point I could barely pick up my feet.

The sun, by now high in the sky, warmed the air though it was also fast melting the ice causing it to give way perilously. Every few metres I fell through the snow crust, up to my knee or sometimes thigh, and I’d have to waste even more precious energy picking myself back up.

I stopped at the highest point, 1,200m, to take a selfie in the endless white desert, causing my iPhone to die in the cold. Irritated to be without stimulating music I battled on in eerie but beautiful silence. How was I feeling? Utterly euphoric: I felt I could run forever.

By now, I knew how to break barriers and turn adversity to my favour. After day one’s 1000m ascent in a 14km ski touring race, I’d slept not a jot, shivering uncontrollably, fully clothed in my four-season sleeping bag, when the camp fire went out. We slept in traditional Norwegian Lavuu tents (much like a tipi) but the wood provided for the fires inside was kiln-dried, so logs burned out within 30 minutes. The subsequent nights I set an hourly alarm to remind me to fuel the fire.

“How was I feeling? Utterly euphoric: I felt I could run forever.”

Day two was fat biking, and a stage that nearly broke every single one of us. With two transatlantic rowers, one regular marathon runner, one keen cyclist, a former professional squash player and a polo player in our midst, as well as entrepreneurs, venture capitalists, risk managers and a top orthodontist, we were all accomplished sports men and women and driven characters. But five hours spent alternately pushing up, and sliding down, 35km of warm, slushy mountains, was hell on earth. Brake at the wrong time and you are catapulted over the handlebars, swiftly followed by a 15kg lump of metal hammering you, quite literally, into the ground.

Pre-race, N60 route planner Rune Abrahamsen had described the terrain as “undulating” but it felt more like mountain after mountain, with each corner exposing not the welcome sight of lavuu tents and wisps of smoke from a camp fire but yet another vast swathe of white wilderness punctuated by peaks to climb.

The cross-country ski race on day three was shortened to 30km on account of our extreme fatigue and lack of technique: most competitors (including me) had done little more cross-country skiing than an hour’s practice the day before the N60 Challenge began. It was here that I sustained serious tears in my hip flexors, but again my time in the mountains proved an advantage, as did my love of Falke socks, while everyone compared blisters each night in camp, my feet were remarkably unscathed.

As I hit the road 5km from the final finish line in Geilo, I glanced at my watch, suddenly aware that if I kept up the pace I could finish my first ever marathon, over snowy mountains after three previous days of marathon-distance events, in less than five hours. Cursing the fact I’d stopped to take pictures I pounded on, spurred on by an encouraging text from a friend at home watching my progress on the race tracker.

“It was here that I sustained serious tears in my hip flexors…”

Thirty minutes later I climbed over the finish line, arms aloft, euphoric to the extreme. I could barely walk, but I’d made it, maintaining my sixth place overall and landing me first place in the women’s division by nearly two hours. Every competitor finished bar one poor chap who was withdrawn by doctors for a serious issue on with his hip. To say he was disappointed would be an understatement.

Abi’s Kit Tips

Helmet — Rather than take separate ski and bike helmets, I used the super-lightweight, breathable Salomon MTN Lab Helmet (salomon.com)

Merrell Capra boots — waterproof walking boots that fit like a trainer, these are designed for scrambling, and saw me through a marathon in the mountains as well as keeping my feet warm and dry around camp (merrell.com)

Backpack — the Salomon Agile 12L was the perfect size as a day-pack, with an in-built water reservoir (crucially, with insulation) and a stretch fit specifically for running (salomon.com)

Compression clothing — I never exercise without this now, and found it an absolute essential for a multi-day endurance event in the cold, to support tired muscles, joints and minimise injury. I used Skins A400 for running and cycling (under padded shorts!), Skins DNAmic Thermals for ski touring and cross-country skiing and Skins Recovery tights every night (skins.net)

Expedition-weight gloves — North Face Nuptse Mitts keep out serious cold, (thenorthface.co.uk)

Sports-specific socks, two pairs for each day — my feet stayed blister-free throughout the entire race and I credit Falke’s quick-wicking and ergonomic cushioning ski touring, cycling, running and cross-country ski socks (falke.com)

The warmest coat you can find — my Canada Goose parka doubled up as a spare blanket at night and kept me warm pre and post-race. (canadagoose.com)

Lightweight, windproof shell — North Face’s new Fuseform Cesium Anorak was the ideal layer, scrunching into nothing at the bottom of my pack (thenorthface.co.uk)

Nutrition — I can’t stomach any artificial goos and gels, which makes taking on 4,000 calories a day while racing hard. I couldn’t do any of my races without the all-natural Shake33 Chia Energy Gels (33shake.com) or Skratch Labs exercise hydration mix (wiggle.co.uk)