'The Toughest Footrace on Earth' starts this weekend — here's what it's like

31st edition of the race, the longest yet at 159 miles. As one of 973 who crossed the finish line, I can attest that the race is not for the faint-hearted.

The route took in towering sand dunes, airless oueds (dried-up riverbeds), and scrambled jebel (rocky hill) ascents.

The distance typically comes in at almost a marathon a day, with the longest stage a punishing double marathon.

Competitors run or walk through 104-degree plus temperatures, carrying their food for the week. Water is rationed. Salt tablets are essential.

Competitors sleep in bivouac tents, which do little to retain warmth when the temperature drops overnight and offer limited resistance to sandstorms.

It is no surprise then that a lot of competitors don't make it to the finish. There were 18 participants who didn't make it past day one in 2016, according to the provisional results, and nearly 60 more dropped out on day two.

In all, around 130 were forced to drop out, often through no fault of their own. The desert is relentless, and there is a large slice of luck involved in surviving what it has to throw at you.

This is what "The Toughest Footrace on Earth" is like:

The event requires quite a bit of kit. We had to carry at least 2,000 calories a day for seven days, with the bulk of this made up by caloric freeze-dried meals. We also had to pack survival kit with items ranging from a venom pump to a signaling mirror.

We flew in to Ouarzazate in Morocco on Friday, April 8, before boarding coaches for the six-hour drive to the first bivoauc.

The bivouac camp has around 170 tents, each sleeping a maximum of eight competitors. The tents are organized by nationality, with large British and French contingents dominating camp. I stayed with three friends and a British runner named Dave who we met on the bus.

The Friday night in the desert gave us a chance to gauge the overnight temperature, and adjust our packs accordingly. It was colder than I was expecting, and so I packed an extra-lightweight gilet.

There was a kit check on Saturday, April 9, where we received our race numbers and tracking device. Our bags were also weighed. The minimum weight is 6.5kg, or a little over 14 pounds, and the aim is to get as close to that limit as possible. We realized after weighing our bags that we had to throw some nonessential stuff out.

The race started at 8.30 a.m. on Sunday, April 10, to the tune of "Highway to Hell" by ACDC.

The first stage was relatively short, at a little over 21 miles, but it included about 10 miles of energy-sapping sand dunes.

I struggled to get my water and salt intake right. I hadn't accounted for being so tired so early.

I decided to take day two easy in a bid to refine my hydration strategy and conserve energy levels for later in the week. I covered the majority of the 25-mile distance with a friend. I felt strong at the end of the day, but my feet had started to deteriorate.

I spent day three, a 23-mile stage across relatively flat terrain, with my friend again. I felt fine from the ankles up, but my feet were swelling more than I had expected, making my shoes pinch. I was developing blisters at a rate.

The stages would usually start around 8 a.m. each day, and the camp was a hive of activity from daybreak to the start of each of stage.

The long day, a 52-mile slog over several jebels, took place on April 13. We knew this was the big test.

The toughest climb of the race came about 6 miles into the long stage. The El Otfal Jebel had an average slope of 12%, and a 30% incline over the last 550 yards.

I stopped to eat some rehydrated biscuits and gravy and a Clif bar at Checkpoint Three (CP3), around 21 miles into the stage. The sun was going down, so we put our head torches on and set off in the dark before stopping at Checkpoint Four (28 miles) for three hours of sleep. Then, at 2.30 a.m., we were off again.

My friend and I stopped for some granola and a cup of Earl Grey tea at CP5, 34.5 miles in to the stage. We were able to sit down and watch the sun go up over the dunes in the distance.

Friends and family were able to track our movements on the MdS website, which used the tracking devices attached to our bags to pinpoint our location.

I finished the long stage, took on some food and got a bit of rest. Later that day, the whole camp got up to see in the last person to finish the stage, and celebrate.

Medical support was provided by Doc Trotters, who were really quite incredible. I arrived in camp each night in pain, and they somehow patched me back together ready to go again the next morning.

We weren't finished there though. We still had a marathon to do on the Friday. The terrain was relatively easy compared to what we had been through earlier in the week, but the heat and cumulative fatigue still made it challenging.

The event finished with a short 11-mile UNICEF charity stage. Everyone was handed a clean T-shirt in the morning to wear, and we shuffled slowly to the finish line.

I made it.

We boarded a bus and headed back to a hotel in Ouarzazate, where we had chance to rest by the pool.