For the survivors who cross the finish line of the 35th Marathon des Sables on Saturday, the six-day, 254km slog across the sands have brought heat exhaustion, blisters, diarrhoea and joy.
"It's so hot! It's unbearable. I cry while walking. I am exhausted, my head is spinning," said Sixtine Morizot, a 30-year-old from Paris as she sank her feet into the sand as best she could.
This year, the temperatures have been particularly high in the Moroccan desert. They reached 52 degrees celsius on the second stage. A competitor died of a heart attack after overheating.
"It's special this year, because there have been a lot of retirements where the main cause was dehydration," said Frederic Compagnon, head doctor of a 45-person team.
"The temperatures are high but not extreme. It is hot and people were not prepared well enough. There are heatstrokes, which associated with high temperatures also cause hallucinations, even comas", he said, adding that he had counted nine runners who had fallen into comas.
Alix Noblat, who appeared in French TV reality show Koh Lanta, lost consciousness during the third stage.
She had literally emptied herself, like almost half of the camp, because of an epidemic of gastro which spread like wildfire.
The nightly bivouacs are animated by vomiting and diarrhoea.
"It's like Jurassic Park, you can hear the vomiting!" Noblat said.
At the race bivouac, the podiatrists are busy.
Every evening, runners lie on their backs and stretch out their legs, offering their blistered feet for treatment.
Compagnon said he saw one man whose skin on the soles of his feet had completely disappeared, leaving the flesh raw.
On Thursday's marathon 86.2km fourth stage, race leader Rachid Al Morabity finished in 8hr 46min 16 sec at an average speed of 9.23km per hour.
- 'I want to go dancing!' -
A few seconds under 22 hours later, Christine Taieb and Valerie Angot, two Frenchwomen, crossed the line holding hands to the acclaim of the other competitors.
They were followed home by Nadjib and his two camels, whose job is to bring up the rear.
"I didn't expect this welcome!" said Taieb, who is running her first Marathon des Sables at 70. She was however penalised 30 minutes for 'exceptional water assistance' during the stage.
"I'm an average woman, I'm overweight, I'm 70 years old, I've worked a lot. But even at 70, you can enjoy yourself. I have worked hard but I feel great, I want to go dancing! But I know that I will go limp when I do my laundry tonight," she says.
At the other age exteme is Anna Kroijer a 16-year-old Dane who lives in London and the youngest competitor. She is running with her father who completed the race in 2014.
"I'm still here. It hurts a lot," she said on Friday evening.
"To cross the finish line tomorrow would be so amazing," she said, looking ahead to Saturday's stage, at 7.7km a relative sprint. "When I think about it. Wow! it's going to be a very intense feeling."
Ahead of Friday's 42.2km penultimate stage, Morizot was bubbly.
It is her first Marathon des Sables.
"And it's my last," she said. "It's the hardest race of my life. Really. I have accomplished something. I came to surpass myself, to push my limits. The contract is fulfilled. I will not do it again".