The Marathon des Sables is this strange mid-life rite of passage that holds the most extraordinary allure for people who need some pep in their lives.
I know - I was one of them. Got the T-shirt (horrible yellow colour); even written the book.
The Marathon des Sables, or MdS as it is known, is a week-long 150-mile trek through the heat of the Sahara. The French Commissaires provide you with water and flapping leaky tents, but as for the rest, you're on your own.
You'll have to carry well over 12 kilos of food and kit.
The blisters are absolutely eye-watering.
And the heat regularly tops 54 degrees.
How hot is 54 degrees? It is drinking 11 litres of water - and never once needing to stop for a pee.
The MdS is a rare antidote to the oh-so congenial lives that we tend to lead in the West. It is an extreme version of "I'm a Celebrity, Get Me Out of Here" - though with more pain, more heat, more thirst and just that little bit more deprivation.
But don't forget the views and the whole experience of wandering through the Sahara in the middle of the night. Everything, from joy to the most complete desolation, is enhanced when you're on foot in the desert.
So - not saying that you ought to set your sights on the MdS. It's only the toughest footrace on earth. But just in case you do, here are my ten Do's and Don'ts.
1. Blisters
Unless you are extremely lucky, you're going to get blisters on the MdS. On the first day, it'll usually be just two or three, but after a few days in the heat, the soles of your feet will be pock-marked with blisters. If things are going badly, your feet might even be "delaminated" - you'll have lost all the skin from your soles. I was nearly sick the first time I saw it.
Wearing gaiters will prevent the worst of the sand from getting into your shoes. Gaiters should ideally be sewn by a cobbler into the soles of your shoes. Without decent gaiters, the sand will quickly combine with the sweat in your socks. Before you know it, you will be running on sandpaper.
Every hour or so, knock out your shoes. Even the very best gaiters will still let through some sand and this will then somehow worm its way through to your toes.
For footwear, you generally want to run in the same shoes that you've been training in, though a size or two larger than normal. Feet sometimes expand by as much as two sizes in the heat - and sometimes they don't. You won't know until you're in the desert. If the swelling gets really bad, take out the insoles.
The shoes need to be fairly robust. You'll be going over a lot of rocks. On the first day, I remember seeing a Japanese guy wearing some very lightweight barefoot running shoes. By the end of the race, his shoes looked like they'd been chewed a dog. His feet were chopped liver.
For socks, go for the Injinji toe-socks. They may look faintly reptilian, but they are your best chance of keeping your toes blister free. (And even then, you can still develop blisters under your toe-nails, which have to be lanced with a syringe. Welcome to the MdS.)
The main thing to remember is that if, after the first 20 miles, you've got a bunch of blisters on your feet, then by day three, you're going to have a whole lot more. So you've got to do something different. Strap up your feet. Change your socks. If it's your shoes that are the problem then... you've got a problem.
2. And how to deal with blisters
There are several ways to deal with blisters, some more painful than others, and all fairly yuk. Some people, particularly the French, swear by piercing the blister with needle and thread, and then leaving the thread in situ so that the blister can drain. Others believe in chopping the blisters clean off.
On the MdS, the general technique used by the doctors at Doc Trotters is to first sterilize the blister, then open it with a crescent-shaped cut, and then to very lightly bandage it so that it can dry out overnight. The next morning, the drained blister is strapped up much more solidly. This procedure is then repeated the next day - and the next - and the day after that too. Blisters never go away on the MdS. They only get bigger.
Be aware that blister-remedies in the temperate West may not work so well in the desert. One runner, an ex-Para, insisted on using Compeeds. He cut the blisters off and then slapped warm Compeeds on to the raw flesh. They quickly formed a second skin, complete with their own little plastic bubble. These can be very effective in the UK. But after three hours of sweat and heat on the MdS, all his Compeeds had been turned into sticky little balls of sand.
3. Pain relief
Most MdS runners take along their own paracetemol and ibuprofen. As any half-decent boozer knows, you can combine the two painkillers to give you a double hit of pain relief.
If the going gets rough, Doc Trotters will give you Tramadol, an opiate, which can delightfully mask even the most savage blisters.
But take a care when you're using painkillers. They of course deaden all the pain in your feet and in your back, but your feet can become so numb that you have no idea what's going on down there. It's only at the end of the day, as you tug off your sandy socks, that you realise that you've done yourself a serious injury.
So by all means take painkillers. You're really going to need them. But if you're doped up to the eyeballs, then every so often you'll need to visually inspect your feet - just to check what sort of damage you've been inflicting on yourself. It ain't going to be pretty.
4. Food
The MdS is a self-supporting race, which means that you have to carry all of your own food, with a minimum 2,000 calories a day. How ever much food you carry, you're still going to lose weight. As diet regimes go, the MdS is right up there with trekking to the North Pole.
Most people survive on dehydrated food, usually pasta, though some of the front-runners get by on dates, rice and raisins.
Spaghetti Bolognese is thought to provide the most energy per pound. One of my tent-mates took this so much to heart that on the first day he had seven Spag Bogs in his backpack. By the end of the race, he had been put off spaghetti for life. Variety is good. You can always swap with your seven tent-mates.
Some runners take out Pot Noodles which, despite their food-for-slobs reputation, are tasty and packed with energy. Mountain Meals were also popular. Take them out of their foil packets to save yourself half-a-kilo in weight.
Breakfasts usually consist of porridge or grain bars, while for lunch, a lot of runners are eating Peronin, which both looks and tastes like lumpy luke-warm custard. If you're hungry enough in the desert, which you usually will be, you'll eat just about anything.
A lot of people take out puddings to have after supper. You will not need them. You'll have been eating sweet stuff from sun up, whether that's sports beans or Peronin powder or Rego recovery powder. The last thing you'll feel like is another sweet dainty before you go to bed.
At the end of the second day, most runners had dumped their puddings.
Oh - by the by. One more thing about food. It is my favourite food story! Last year, when I was in the MdS, it was learned that a member of the Eurosport team had been given a can of Coke. Since this was against the entire MdS ethos of being a self-supporting race, the Eurosport team was docked three hours. This was to prove fatal. They came second in the overall standings, losing to Scotta Roata Chiusani by 2 hours, 59 minutes and 20 seconds. Ouch!
5. The Golden Hour
This is far and away the most important tip for running not just the MdS but any endurance race.
The Golden Hour refers to the hour directly after you've stopped running. It is vital to a runner's recovery - and if you want to have any hope of completing the MDS in good shape, then you need to stick to this religiously.
Every single one of the elite runners - without exception - adheres to the Golden Hour. It's beautiful, it's brilliant, and even if you forget everything else, you want to remember the Golden Hour.
It's the time when you have to eat.
And it's the time when you have to have your feet up.
It's that simple!
But you'd be amazed how many runners don't bother to do it.
Food is much, much more effective at helping your body recuperate if it is eaten within an hour of you stopping. A lot of runners have Rego recovery powder - just mix it up with water and chug it down. But you have to eat it in the Golden Hour.
The other thing you have to do in that first hour is look after your feet and legs.
Just lie down and prop your feet up on your backpack so that they're about a foot off the ground. This will help the gunk (technical term) drain out of your legs and into your body. It is heavenly. Even when the wind is blowing a gale, and the sand is being whipped up at the side of the tent, there you lie with your feet on your knapsack, dirty and sweaty and feeling just utterly ecstatic. In my book, The Woman Who Was The Desert Dream, I describe it as being like an orgasm. Only it's actually better than that. This rolls on for a full hour. It may just be the endorphins, but more than likely it's the total relief of not having to walk another step and not having 16 kilos pinned to your back.
6. Little and Often
As with anything in the MdS, every runner will have their own particular way of doing things. So there will be a lot of different ways that runners are ingesting their water and all their energy food.
Well, no swanks, but... this is the best way. Tried and tested. I give you: Uncle Billy's Water-Bean Regime.
With both your food and your water, you want to be taking it little and often. You do not wait an hour and then guzzle a pint of water in one go. You do not chew down ten sports beans in a single sitting. (What's a sports bean? Exactly like a jelly-bean. Only quadruple the price.)
Every ten minutes, have a few sips of water and chew on a couple of sports beans.
You need to get into a routine. The heat and the sun can play weird tricks with your mind, so that if you're not in a rhythm then you can forget to keep drinking, and if you forget to keep drinking, well... that's bad.
Even if you think my little routine is ridiculous, then do not be tempted to drink just when you feel thirsty. If you're feeling thirsty, it's probably too late. You only start to feel thirsty long after you've started to overheat.
Every hour on the hour, take your two salt tablets. (They give you over 100 of these at the start of the race.) You need the salt tablets because you'll be sweating out nearly a gallon of water in the day. Your face and your rucksack will be covered in beautiful tide-lines of salt scum. After the first day, I realised that my sleeping-bag was completely soaked. I thought a bottle had cracked. But it was just my sweat.
You'll also need a couple of packets of electrolyte pills to replace all the electrolytes that are being sweated out of your body. Most likely you'll have two water bottles on your shoulder straps; just lean your head and sip. Though keep one bottle pure. You very quickly tire of the taste of electrolyte tablets.
Only drink your last half-pint of water when you know - for certain - that the next pit-stop is only a few minutes away. Distances in the desert can be very deceptive.
One more thing: you still need to keep drinking at night. The fourth day is a double marathon, 52 miles, and most runners will be tramping through the desert in the middle of the night. Hugely exhilarating, as you follow these winking lights in the distance, and as you realise that this is the Marathon des Sables - and that you are a part of it.
If you're moving then you'll still be sweating. So you have to keep on drinking. And chugging those sports beans.
7. A Thermarest
Since you've got to carry all your own kit, some runners try and save on weight by not taking a Thermarest. But these durable little mattresses - like a small Lilo - only weight about 300 grammes and they are essential.
Firstly, because it's damn uncomfortable sleeping on the bare ground. Each tent has a rug, and there are always going to be stones and rocks underneath the rug. Invariably, these stones will be positioned right in the small of your back.
Secondly, it can get really cold at night - really, really cold. If you're lying direct on the ground, all your body warmth will be wicked away into the earth. A Thermarest keeps you insulated, so that your body heat stays in your core, where it's meant to be.
A decent sleeping-bag is also good. You'll be spending a lot of time in it. Most runners go to sleep at around 8pm. I'm not talking luxury. But if you're buying a sleeping-bag, it might be worth spending a little bit extra.
One more tip: Best way to prepare for the searing heat of the desert.
Some people prepare for the heat by training in eight layers of clothing. Some people exercise in special heat rooms.
Forget it! The best way to prepare for the heat of the Sahara is to take several long hot baths. It's brilliant! An hour-long hot bath, feet up, with a book and a glass of wine. Now that, my friend, is the way to psyche yourself up for the delights of the MdS. (May not be quite so good, I admit, if you're a guy looking to have children any time soon. Sperm does not take well to being deep-fried in a bath for an hour.)
8. Health and hygiene
Bad hygiene is one of the surest ways to get yourself drummed out of the MdS. If you've been rolled over by a stomach bug, then it's unlikely that you'll be able to complete the next 24-mile stage in the Sahara before the cut-off time.
You have to be absolutely meticulous with everything that you put into your mouth. Ideally you need a small pot of antiseptic gel, so that your hands are always clean. It's always a real tonic to high-five the local kids who are watching this troupe of crazy runners trot past their front doors. But when you're done, you need to clean your hands.
And also - of course - after abluting in the MdS latrines.
Be wary about drinking any of the local water, particularly from nearby wells. And it's risky to swim in the ponds or the rivers. There are all manner of bugs waiting to get their claws into you.
If you're squatting by a rock, give it a kick to check for anything underneath.
Knock out your shoes in the morning, to check nothing has climbed in overnight.
If you've got the runs, then you need to knock it on the head immediately or you'll be out of the race. Imodium is the best thing for this - by far.
Eating chalk tablets will not do the job nearly quick enough. They take hours to take effect and by then it'll be too late.
9. Relish your time without a mobile
One of the best MdS rules is that mobile phones are banned. It is beautiful. You can go the entire day without hearing a single ring tone.
Some scamps do, of course, bring their phones. More fool them. The MdS is this golden week of just you and your tent-mates and the desert, and with very little contact from the outside world.
Email print-outs are delivered in the evening, and you can also send one short email from the communications tent (accompanied by the sound of birdsong and Gregorian chant. Surreal but lovely.)
But for the rest, you've got nothing else to do but cook and read and talk and gaze out at this infinity of sand, which was there millions of years before you arrived, and which will still be there long, long after you're gone. It all rather puts things into perspective. Especially when you realise that you'll be trekking through this wilderness the next day.
A week in the desert is as good a way as any of taking stock of your life. Of weighing up what matters - and what doesn't.
Some morons complain on the MdS of being "bored". They're missing their Facebook and their constant news updates.
Better by far to embrace your week without a phone, and your week of not being hectored by your family, your work-mates and your friends. It's just you and your new best friend, the Sahara.
Incidentally: all the world's great monotheisms - Judaism, Islam, Christianity - originated in the desert. Just a thought.
10. And finally: remember to take the next step
At some stage in the MdS, it is pretty likely that you will feel like you are in a living hell. You'll be hot and parched, and your blisters will be screaming, and the straps of your rucksack will feel like two pieces of cheese-wire sawing through your shoulders.
And after a bit, you will realise the blindingly obvious: what on earth is the point in me continuing with this fantastically stupid race? Why on earth am I putting myself through this hell of sand and heat? It's all so painfully ridiculous - 150 miles through the Sahara, with this great weight strapped to your back. Why not make it 300 miles through the Sahara - and dragging all your own water along with it? Will it really make you more of a human being if you ever do complete this farrago and get that little medal at the end? Will it ever really compare to what your grandparents went through in World War II?
All these points can basically be boiled down into one incontrovertible nub: What's the point? What's the point of completing this next ghastly stage, when you've got another stage the next day; and then after that you've got the monster, the double-marathon... And...
What. Is. The. Point?
Well - if you're doing the MdS, or any other endurance event, then at some stage many of these thoughts will occur to you.
And then, if you carry on walking for a few more minutes, you'll start to think about something else. You might start to admire the shadows on the ground, or the hill up ahead, or the dung-beetle who is doughtily climbing up a dune.
You may even, on occasion, experience the most complete euphoria. (Do not worry - this feeling will soon pass.)
The point is that when you're alone in the desert, you'll be thinking a lot of things, some of them positive, and a lot of them negative. That doesn't matter. That's fine.
But you still have to take the next step. You can definitely think about quitting. It would be strange if you didn't think about quitting.
But you still have to take the next step. And then the next step. And then the step after it.
When the going gets tough, keep things small. Just concentrate on taking the next step.
If the going gets really rough, and if your morale has hit rock bottom, then stop for a break. Cook yourself up a hot meal. Hot food is the very best pick-me-up there is. (Maybe up there with sex. Not quite sure. There wasn't that much sex going on in the MdS. At least amongst the runners. But as for the Commissaires in their white-tented city... It was said that they were all at it like sea-otters.)
Oh - and one more thing. As you take the next step, and as you dwell on the misery of your blisters and your sun-burned neck, don't forget to stop and smell the flowers. There are not many flowers in the Sahara, but there are a few, worming their way up through the sand.
Somehow, they just seem to thrive on adversity.