The Gobi Desert, September 2018. British runner James Poole, having passed the 4,000m-high summit that marks the highest point in the Ultra Gobi, descends into a valley devoid of colour or life, with nothing but a biting wind and a dusty trail to keep him company. Two days and more than 200km into the race, this is the halfway point. The approaching night and altitude will see numerous runners succumb to hypothermic conditions.