IT’S stuff most people would run a mile to get away from. They are advertised as brutal, agonising, the hardest; through jellyfish-infested sea and icy rivers, across wind-scoured mountains and splintered scree.

But rather than putting people off, adventure races ranging from merely gruelling to almost incredible feats of endurance are attracting tens of thousands of entrants. They’re paying up to £350 for the pleasure and they are helping fuel Scotland’s booming outdoor tourism business.

While events such as well-known international brand Tough Mudder race over man-made obstacles, the contests taking off in Scotland use the natural obstacles of landscape, water and our sometimes awful weather.

These adventure races can include multiple disciplines such as running, swimming and cycling, or just one. They can carry brands such as The Starman, be part of a series such as the Nordic-inspired swim-runs, or stand alone. The key is they are organised races in some of the most challenging environments in Scotland.

At the “accessible” end – aimed at the reasonably fit everyday adventurer – are races such as the Mighty Deerstalker, a night mountain run of up to 10 miles (16k) around Innerleithen in the Borders. Some raise cash for charities, such as Perthshire’s Rob Roy challenge, a 14-mile (22k) run and 56-mile (90k) bike ride.

At the extreme end are City To Summit – a total of 41 miles (66k) of running and 115 (185k) miles cycling from Edinburgh to Fort William via the summit of Ben Nevis; and possibly toughest of all, the Celtman!, an Ironman-style triathlon involving more than two miles of open-sea swimming, 125 miles (202k) of cycling, then a full 26.2-mile (42k) marathon over two 3,000ft-plus (914m) mountains.

It’s not clear how many such events exist in Scotland, but there are many dozens, ranging from small-scale ones such as Inch By Inch, a swim-run around the isles of Loch Lomond attracting 90 people, to big events such as the Coast To Coast, where 1,750 people run, cycle and kayak 105 miles (169k).

So what’s behind the boom, who’s making it happen, and who’s cashing in on it?

Jim Mee started his Rat Race event firm with a multi-discipline race in Edinburgh, and now runs five Scottish events – including the Deerstalker and Coast To Coast – which attract 20,000 people a year. They often come with friends and family, so the events will bring 30,000 people to mainly rural locations.

At the Deerstalker it’s mainly locals and other Scots. The Coast To Coast draws largely from England and Europe, with 150 from the Netherlands and Belgium. Racers gather in Nairn, paying more than £200 each to enter. It generates £400,000 in turnover, much of it spent with local suppliers. Events are often outside the main summer season, increasing their value to tourist operators.

“When an event rolls into town in the shoulder season, spring and autumn, the beds are filled for miles around when they would normally be empty,” says Mee. “We can be hiring every coach on offer in the area and we also have to book accommodation for our crew.”

There is a knock-on effect too. “People fly up from London, and are amazed how easy it is to get here. The legacy is they then come back with families on holiday.”

As well as bringing in money, people take a pride in hosting tough competitions. Locals delight in the Deerstalker, with sports clubs entering en masse.

Celtman is based in Torridon. Cathryn Field runs the Tigh an Eilean hotel in Shieldaig there, and says: “Sheildaig villagers think it’s great. They finish their swim in the village and lots of people go out to see them coming out the water and cheer them on. Locals have a go at the event too.

“Of course it is great for local businesses – if you want to stay anywhere closer than Inverness on the weekend Celtman happens, you have to book your accommodation the day the draw is done.

“And a big thing is they come back with friends or with their wives or families for longer stays, once they realise how amazing it is up here.”

A downside is the athletes’ odd diets and tendency not to drink: restaurant and bar takings are lower. It would be better too if Celtman was in the village’s quiet spell in early July instead of June. But, she says: “You can’t quibble with something that brings 1,000 people here.”

Frazer Coupland is a director of Lochaber Chamber of Commerce and has his own company, No Fuss Events, which runs mountain bike and adventure running races for about 5,000 competitors. One combines skiing and cycling.

He says the weakness of the pound and the “staycation” trend is helping to fuel business, but adventure races took off after the Mountain Bike World Cup came to Lochaber’s Nevis Range ski centre in 2002 and the Adventure Racing World Championship came to Scotland in 2007.

He believes traditional tourist businesses can cash in, despite some adventure events leaving other tourist attractions underwhelmed as all local beds get booked by racers and spectators.

He says: “There is clear evidence that sports tourism and sports-event tourism is much better than blue-rinse tourism – someone who comes to an event is much more likely to spend money in the local economy than someone coming on a bus tour.”

He too sees the events as a great way of persuading people to have other holidays in Scotland.

“This is because as well as the event itself we are trading on the landscape, the natural capital as we refer to it, and that part of the experience is repeatable.”

VisitScotland has supported some adventure races and Paul Bush, the national tourism organisation’s director of events, agrees with Coupland that scenery is key. “We’ve got some of the best landscapes in the world, and we are building expertise within the market, getting really good companies that deliver great events,” he says. “For Scotland it could become a real niche market and it opens up some destinations that are quite remote, doing a really good job for rural and local economies.”

Events companies constantly think up new challenges, and expect the sector to continue to grow. Last year saw the UK’s first night triathlon, the Starman near Aviemore, consisting of 1.2 miles (2k) swimming in Loch Morlich, a 56-mile (90k) cycle, and a half-marathon over one of the UK’s highest mountains,the 4,084ft (1245m) Cairngorm.

Safety in challenging environments is a key issue for organisers, and they believe it’s one of the reasons people take part in events rather than just doing it for themselves: it’s an opportunity to take on wildly difficult stuff with a safety net.

Celtman competitors must have their own support team, and organisers check on racers to ensure they can complete the course, but no experience of wilderness is necessary: “What we’re doing is allowing people to have an adventure but safely,” says race director McGreal. “We do organisation and safety assessment, the boring back room stuff, so people who have not got big mountain experience can do it. We are the safety net.”

2015 saw the first Glen Coe Skyline run, taking in the highest mountains in one of Scotland’s most serious Alpine landscapes, covering two ridges regarded as real mountaineering.

On Curved Ridge on Buachaille Etive Mor, and the neighbouring Aonach Eagach ridge, a slip could be fatal, and there is danger from stonefall. The organisers had to issue the warning often given for mountaineering activities: this could result in death.

Gary Tompsett, a 15-year veteran of events and now a race “architect”, designed that course. He says it took a leap into a “world of risk that no-one else would touch".

But he says things will soon go further, with events combining serious, hazardous ice climbs, and ski descents. “The climb people have been doing on Ben Nevis will become a race,” he says. "They will do it with short skis on their back and then ski off down a low-graded gully climb, then do another climb and ski off and so on. That will happen.”

THE ADVENTURERS

“It’s like trying to eat an elephant,” says Sean McFarlane. “You have to cut it up into manageable chunks. Because if you stand on the start-line and think ‘my God I’ve got to do 15 hours of this’, you wouldn’t do it.”

The film-maker and journalist from Dollar has tackled Celtman four times, coming second once, plus many other adventure races.

To eat the elephant, he divides Celtman in his mind into shorter sections, and is scrupulously organised: he cycles with a spreadsheet taped to his handlebars.

Another clue to the psychology needed for such events is his attitude to the gruelling climb to 3,000ft near the end of Celtman. For him it’s a rest. "You are using a different set of muscles, so you can treat that as some form of recovery,” he says with no hint of irony.

Such determination, though, can be a mixed blessing. Graphic designer Scott MacMichael, 37, from Alloa is an adventure race addict, having at one time competed in a dozen events a year around the world.

His “personal Everest” was his first crack at City To Summit last year. He trained hard, but

three days before it he came down with a stomach bug he later found was the dangerous e-Coli infection, picked up on land used for livestock at another cross-country event.

Despite that he took Imodium and lined up for the start at 4am at Edinburgh Castle.

“I made it through the 15-mile initial run, and the 115 miles on the bike to Kinlochleven,” he said. “The weather was as bad as it gets in Scotland in July, having to pedal downhill into brutal headwinds. I had stomach cramps but managed to keep going. I went to set off for Ben Nevis and got 200m into it – but that was as far as I got.”

His gut just couldn’t cope any further, but there is still pain and regret in his voice as he talks about his failure: “Lots of people think I was daft to try it ... I still felt I could have given it a go but had to make a decision for safety.”

He’ll be back at Edinburgh Castle for the start this year.

Sports physiotherapist Danny Wray treats adventure racers and says repetitive strain injuries make up almost all their problems. “People who have been doing these things for many years tend to be ok,” says Wray. “It’s the people who start a bit later in life and push it that have trouble. Instead of just concentrating on, say, running, they need to work on strength and flexibility, take a more holistic approach, and listen to what their bodies tell them.”

Paul McGreal was inspired by Torridon’s scenery to set up Celtman with a group of friends. A triathlon competitor himself, he says: “It’s a bloody hard day. The phrase we used when we set it out was that the course was probably at the limit of what can be achieved in a one day.”

To push yourself like that involves a particular type of thinking, “response modulation”, according to Stirling University sports psychologist Dr Calum Arthur, who studies endurance events.

Put simply, response modulation is using your mind to overcome the messages your body gives you – to stop hurting it so much, maybe – and carry on.

“You have to be very goal-focused,” says Arthur. “The key bit is the achievement, doing something that’s very difficult, very special and very few human beings would be able to do.”

The reward can just to be to join the rarefied group who have completed such events: “The more extreme you go, the fewer people there are who’ve done it, and there tends to be more shared camaraderie. It might not be verbal but there is recognition within a small group.”

Adventure racing has been dominated by men, but some such as the Coast To Coast now have a gender balance. Physiotherapist Caroline McKechnie from Aberfeldy worked helping contestants at the Artemis Great Kindrochit Quadrathlon around Loch Tay from 2008. That lured her into tackling the 57-mile (92k) run, swim, cycle and kayak trip three times. “Seeing other people do it, I thought it was insane,” she says

“I had done a 10k run, that’s all. But working in the environment you get curious, you think you might like to try this, so I started with the smaller Rob Roy Challenge and then trained for the quad.

“There’s definitely a different adrenaline buzz when you’re part of an event – you go faster and I really enjoyed crossing the finish line.”

When she started working at the quadrathlon it was male-dominated but the balance is changing, and she adds: “I certainly didn’t feel unusual taking part. It’s not an environment that would put you off as a woman.”

There seems to be no age cut-off either: Frazer Coupland of No Fuss Events in Lochaber is regularly asked for a 55-plus category for his mountain bike and running races.

“I’m now being asked for a 65-plus category,” he adds. “That’s the same group of people, just getting older. This is important to them, it’s how they read their lives and they don’t want to stop.”

SIX OF THE BIGGEST AND BADDEST

The Starman £125

Loch Swim 1.2 miles (2k); road cycle 56 miles (90k); run 13.1 miles (21k) over 4,084ft (1,245m) Cairngorm

True Grit Events say: “Come and have a go if you think you’re hard enough.”

Marathon de Ben Nevis £50

40 miles (64k) round the country’s highest mountain

No Fuss Events say: “We are taking the bubblewrap away ... you will need motivation and tenacity.”

The Ultra Tour of Arran £238

Run 58 miles (93k) in two days across the island

Rat Race events say: “The day two route is one tough day, made harder by already tired legs.”

The Coast To Coast

£320

Run, cycle and kayak 105 (169k) miles from Nairn to Ballachulish in one or two days.

Rat Race events say: “You’ll face all that Mother Nature has to throw at you – and she is heavily armed in the Highlands”

The Celtman! £350

2.4 mile (3.8k) open-sea swim; 125-mile (202k) road cycle; 26.2 mile (42k) run over two Munros.

The Celtman! team says: “You can bet it’s going to be pretty damn extreme.”

Glen Coe Skyline £99

Run 32 miles (52k) with 15,583ft (4,750m) ascent – think climbing Mont Blanc from sea level

Ourea Events say: “The nature of the challenge is very severe and there is a risk of serious injury or death.”

All prices are maximum for individual entry