: Runners must carry all their own food and equipment for the duration of the six-day race in extreme desert temperatures.
The "Toughest Race" mentioned is the , a 251-km (approx. 156-mile) ultramarathon in the Sahara Desert. Toughest Race On Earth With James Cracknell
: Exotic endurance: Tourism, fitness and the Marathon des Sables . : Runners must carry all their own food
The reference to a "paper" in relation to refers to an academic journal article titled "Exotic endurance: Tourism, fitness and the Marathon des Sables" by Debbie Lisle. The Academic Paper Toughest Race On Earth With James Cracknell