Mark Pollock (30) is celebrating after setting a new world record by finishing the Tenzig-Hillary Everest Marathon in 16 hours, 27 minutes and 39 seconds on June 3.
Not only has Mark become the first visually-impaired person to complete the Everest Marathon, he did so after having a few weeks rest after coming 25th in the Dead Sea Ultra Marathon in April.
Both challenges presented Mark with different weather conditions and different extremes – for the Dead Sea Marathon he finished at 400m below sea level while for the Everest Marathon he reached a massive altitude of 5,356 metres above sea level.
It was challenge in itself for Mark to reach the starting line of the Tenzig-Hillary marathon and just reaching the starting line – there was a 15 day uphill trek to base camp before they started running on day 16.
Mark, who was accompanied by his challenge guide John O'Ragen, said; "Running the Dead Sea Ultra Marathon was pure sport; Everest was pure adventure. I knew the terrain would be challenging but I didn't realise how tough it would be.
"John and I have raced in all sorts of events and conditions - the heat of different deserts, freezing temperatures at the North Pole, over boulders in the mountains - but Everest combines it all and more.
"It is not just a sporting event, it is an adventure race, a marathon and an expedition all in one."
Speaking of the challenging conditions they faced, John commented; "Everest is different to everything I have experienced before, just getting to the start line is as much of a challenge as the race itself – it takes nearly two weeks to get there and there are no guarantees of making it all.
"We went there to race against the other competitors but ended up competing against the terrain, lack of communication, sleep deprivation, altitude, food adjustment, the cold and then finally the race itself."
Despite having lost his eyesight nearly a decade ago, Mark is no stranger to participating in extreme physical challenges. He has won a silver and bronze rowing medal in the Commonwealth Games, completed six marathons in one week in China's Gobi Desert, competed in Ironman Switzerland and kayaked non-stop across the Irish Sea.
And on the sixth anniversary of him losing his sight, he also ran a marathon at the North Pole. But his challenges began when his took his first walk alone with his guide dog, Larry. "I can tell you that nothing compares to that first walk alone with a guide dog.
"I was scared and overjoyed all at once. I can best describe it by saying that I was literally shaking with the feeling that I'd got my life back," he said.
To find out more about Mark and Larry's story visit www.guidedogs.org.uk and to discover more about Mark's speaking and research go to www.markpollock.com.