A marathon runner went as far as drinking bat blood and his urine to survive over a week while competing for the toughest foot race in the world, the Marathon des Sables, in the Sahara desert.

The former Olympic pentathlete, Mauro Prosperi, signed on an agreement telling the organizers of his preferred burial site before embarking on the six-day, 155-mile Marathon des Sables through the Sahara desert, reported The Independent.

In an interview with the BBC, Prosperi described his initial feelings upon arriving in Morocco as being "bewitched" by the landscape, however following a violent eight-hour storm he said, "the sand whipped my face - it was like a storm of needles."

After facing the storm, Prosperi was only left with a knife, a compass, a sleeping bag and some dehydrated food.

Prosperi reportedly tuned into his survival instincts that reminded him that well-hydrated urine can be a lifesaver in similar times, and so he stocked up his urine in a water bottle.

He even peed on the food to cook it without using the bottled up urine in an attempt to save up. After discovering a Muslim shrine in the desert and climbing onto its rook, Prosperi found a colony of bats.

"I decided to drink their blood. I grabbed a handful of bats, cut their heads and mushed up their insides with a knife, then sucked them out. I ate at least 20 of them, raw - I only did what they do to their prey," said Prosperi.

After two failed attempts of being spotted by planes, Prosperi tried to commit suicide, but after failing in his attempt, decided to head towards the clouds.

Prosperi soon discovered an oasis and fuelled up on water.

He finally made human contact after nine days when he stumbled upon a group of women in a tent who contacted the police for help.

Prosperi was told that he had strayed paths and was now in Algeria, 219km off course.

Doctors at a hospital in Mauritanian, Western Saharan and Moroccan borders, told Prosperi that he was 16kg less from his starting point and weighed only 45kg.

Prosperi was one of 80 participants at the marathon that now hosts up to 1,300 participants.

Following the incident, it took Prosperi two years to fully recover and for his body to accept anything other than liquids.

Four years after the gruelling marathon, Prosperi was back to Marathon des Sables where he conquered the route in another life threatening trial.