For most, the thought of running a marathon seems an impossible feat.

The Comet: Competitors at the start of a stage of the Atacama Crossing raceCompetitors at the start of a stage of the Atacama Crossing race (Image: Archant)

But after completing his first 26.2-mile race last month, Mark Robertson visited the driest place on earth for a challenge only a few are mad enough to sign up for – the Atacama Crossing.

The Comet: Mark Robertson during a climb.Mark Robertson during a climb. (Image: Archant)

The 30-year-old’s first marathon experience – the Marathon du Médoc – involved 23 wine stops in the south of France, a world away from the 155-mile race the former Hitchin Boys’ School student completed earlier this month in the Chilean desert.

Mark was one of 161 competitors to take to the start line on October 5, and was among the 126 who made it to the finish a week later in a time of 55 hours and 52 minutes.

The journey there involved a 24-mile first day, followed by distances of about 26.3 miles and two 24.9-mile legs before the ‘long march’ on day five – a 47.5-mile stage which took Mark just over 21 hours.

Competitors, who spent each night at a desert camp, were then given a well-earned day of rest before completing the final stage – a 6.6-mile leg to the finish.

Mark had to carry his own supplies each day and was only able to top up his water containers at six-mile checkpoints along the route.

The business development manager, who lives in Hardy Close, Hitchin, ran the race to raise money for mental health charity Turning Point, who his brother David has been supported by.

About the experience, he said: “I had my own motivations for doing this – I do like a big challenge. I started off in shorts and a T-shirt but got really bad sunburn so had to wear leggings and long sleeves in temperatures of up to 44°C. The terrain at times meant you physically couldn’t run and I had to walk almost all of it.

“8am was the earliest you could set off each day because of cold temperatures overnight but after the first couple of hours it got so hot – there were many hours of suffering.

“Towards the end of day five I had to have a medical break for about an hour and a half as I was suffering in the heat. I lay down and couldn’t move.

“Eventually I managed to get some food down me and crack on for the final four miles – you just have to get on with it.”

Mark, who returned to work in London just two days after finishing the Atacama Crossing race, has no plans to take the next year off.

So far he has raised about £1,300 for Turning Point, which has a base in Stevenage, but hopes to reach a fundraising target of £2,000.

To sponsor Mark, visit www.justgiving.com/MarkRobertsonrunning.