On their latest adventure, Ben Fogle and James Cracknell raced to the South Pole. But their journey of discovery revealed as much about them and their friendship as the Antarctic

I have to confess, I'm not sure I understand why anyone would want to row across a 4000-mile wide ocean or ski across 800km of frozen wilderness with only cubes of cheddar cheese, salami and chocolate for comfort. Obviously, I didn't say this to Ben Fogle or James Cracknell.

At least not immediately. There's the practical difficulty obviously, but more than that, I've always harboured the suspicion that these Boy's Own adventures are, at some level, about avoiding being a grown-up.

If that was the intention behind TV presenter Ben Fogle and Olympic rower James Cracknell's latest adventure, the Amundsen Omega 3 South Pole Race in which they retraced the steps of Captain Scott in temperatures as low as minus 40 to reach the South Pole, then it certainly didn't work out that way.

As it turned out, their journey to the bottom of the world, as one of six three-man teams, was no escape. To say that their expedition was fraught with emotional trauma would be an understatement.

There were practical problems: they lost their first team-mate, the actor Jonny Lee Miller, when being on camera (a documentary of the journey has been made, with the first part showing tomorrow] proved too much for him. They found his replacement, Ed Coats, by advertising on BBC Breakfast and in the Telegraph, doffing their caps to Ernest Shackleton by cribbing a line from the ad he used to recruit men for his first Antarctic expedition: "Men wanted for hazardous journey…".

Then there were the physical obstacles. Their training regime collapsed when Fogle discovered he had leishmaniasis, a tropical disease he'd picked up while filming in Peru. The infection had to be treated with chemotherapy that made him feel sick and weak and bagged him a three-week hospital stay, putting his participation in the trip in real jeopardy.

"I'd put 18 months into preparing and the thought that it might not have happened really would've ruined my life," he says. "That's how it felt."

Emotionally too things were far from straightforward. While he prepared for his adventure, Fogle and his wife, Marina, found out that she was pregnant. Sadly at the three-month scan, just before Fogle was set to leave, no heartbeat was found. They'd lost their baby.

"It was terrible," he says. "I'd got through the whole leishmaniasis thing, everything was planned. The three-month scan was going to be just before I left and it was going to be brilliantly exciting. Marina and Bev (Cracknell's wife] were going to be pregnant together and we'd get back from the Antarctic and they'd both have their big bumps – you plan it, of course you do, you run away with your dreams.

"It was incredibly sad, one of the saddest moments of my life. And it suddenly threw everything into disarray – what was I supposed to do? Was I supposed to go? Was I supposed to stay? Even if my wife said she wanted me to go, which she did, was I still supposed to go?"

Marina did want Fogle to go. Her thinking was that the situation they were in was dreadful, and by Ben missing the event for which he'd been training for months, it would only feel worse.

"Saying goodbye to Marina this time was one of the worst, most miserable experiences I've ever had. Both of us were hysterical, in tears. I did ask myself if we're this upset and miserable why are we doing this?"

It's a good question.

"I still don't really have an answer," he says. "My only way of explaining or rationalising why I go off and do these extraordinary trips is because I don't think you can fully appreciate what you have in life unless you take risks and take yourself out of that comfort zone you live in."

For Cracknell, preparing for the South Pole trip was a breeze in comparison to the process leading up to rowing across the Atlantic as he and Fogle did in 2006. But still there were issues.

His well-documented panic before the Atlantic trip, partly about his own life – retiring from his sport, coping with being a father – caused real problems in his marriage. "Post-Atlantic was all pretty tough," is how he describes that period, but according to press reports, it was a tad worse than that. Cracknell's wife gave an interview in which she said she didn't know if their marriage would survive.

This time it was different. Instead of making the decision to go on his own, Cracknell and his wife discussed his plan and decided that it could work for them. Cracknell himself was in a better place: "properly retired", enjoying being with his son, Croyde, who'll be six in September, and looking forward to a new baby due a month after his return (Kiki, who's now three months old]. There was still a sadness, though. Cracknell's sister lost her baby late in her pregnancy. It gave him not only a real taste of grief, still palpable as he speaks, but it refocused his mind on his own life.

"A trip like that does make you realise how much you miss people and what's important," he says. "You think about how you ought to be to them and how you inspire them. There are lots of things you can do to improve your family whether you're at home or not.

"People do make big decisions off the back of being out there for a long time. Some people want to go straight back. That hasn't happened." He laughs. "In a positive way, though, you make decisions about what you're going to do – spend more time with your family, spend more time outside. Then you've got to make it happen."

Meeting Ben Fogle and James Cracknell on the same day but in two separate locations is a bit like being the host of a strange version of Mr and Mrs for one day only. OK, they're not a couple (although Fogle says they bicker just like one, much to the amusement of their wives) and our soundproof booth is several miles of bustling central London, but still, they're a duo and I'm getting them solo. If I thought we'd be talking about carabinas and extreme gear, the practicalities of an Antarctic adventure, I'd have been wrong. In fact this is about emotions, the mental battle a slog across the ice entails and most interestingly of all, what makes them a team.

"The great thing about James and I is that our friendship is based entirely on honesty," says Fogle, eyes wide, earnest, leaning forward. "James is, without doubt, the most honest person I've ever met. But," he pauses, choosing the right words, "not in a nice way. He can be quite brutal." Accompanying this killer blow is a huge, dazzling,TV-presenter smile.

To bring you up to speed: Fogle and Cracknell met at a drinks party some years ago. One a TV presenter looking for a challenge and a way to break out of daytime telly, the other a double Olympic gold medalist wondering how to move on from a life spent training relentlessly for a six-minute race that came around every four years. The similarities? Two men looking for the next step in life and a homely, wholesome handsomeness – floppy hair, natural tan, nice teeth. The differences? Cracknell is ruled by an iron streak of competitiveness ("he even has to win at shopping" says Fogle) loves frat-boy humour and specialises in searing, no nonsense honesty. Fogle, on the other hand, is the eptiome of niceness with lashings of puppyish charm and an unshakeable "it's the taking part that counts" attitude. A likely team they are not.

And yet that's what they've become.

Not being much interested in half measures they got to know each by spending 49 days in a 20ft boat, much of the time naked, rowing across the Atlantic. At the start of their voyage, Fogle says they hardly knew each other and in fact he suspects they didn't much like each other, but by they time they clambered on to dry land, tanned and skinny like two castaways who'd just found their way back home, the bond was forged.

And it's only been strengthened by their experiences in Antarctica, with unforeseen consequences for both of them.

"The moment when James gave me his weight was totally unique," says Fogle of the last stretch of the gruelling race. Cracknell, suffering with pneumonia and severe blisters, his energy depleted by weight loss, off-loaded some of his gear on to Fogle's sled. It was the moment when everything changed. "I knew it at the time, it didn't pass me by. I knew it was monumental in our friendship and in James's life."

If carrying a bit of luggage doesn't sound earth shattering then allow me to explain the intricacies of the Fogle/Cracknell dynamic. Until this point, Fogle was the weakest link, the lightweight, less driven, less focused, the one trailing in Cracknell's wake. But no more. Suddenly, something shifted. It was a key moment for both of them individually, but as a pair they just got stronger.

"James is my best friend now without question," he says like a 12-year-old back from boarding school with tales of a new chum. In fact, he's just come back from a holiday in Italy where he and his wife Marina have been staying with ten friends. Some of the group have been going out for a run every day. Fogle has too, but not with everyone else. He's been going alone.

"I don't feel comfortable running with other people, but I would with James," he says. "With my friends I'd probably be a better runner and with James I'm worse, but I still feel more comfortable with him. It's very strange."

He says that he ran the London marathon to "impress James". And when he didn't, finishing an hour after Cracknell and slower than both Ronan Keating and Amanda Holden (prompting Cracknell to taunt him that they were considering taking Holden to the Antarctic rather than him) he was "gutted".

"I've always wanted to impress James. I still do."

Cracknell, true to form, is much more low key about all this. It's clear that the South Pole race has been a profound experience – not least physically given he ended the race weighing what he did when he was 13 – but when I mention Fogle's quest to impress him, he laughs and looks embarrassed. Obviously he likes Fogle, but he's less gushy, more specific in his praise. "Ben is brilliant in front of camera," he says, "He's so personable".

The book the two men have written recounting the race is a split narrative shared between the two of them. They only got to see the other's account when the first manuscript was produced. How did Fogle feel reading Cracknell's version?

"The only way to describe it is to think of when you were at school and you'd get a report," he says. "I used to hate reading even one line, 'Ben needs to try harder' or 'Ben seems to be struggling'. So imagine reading 300 pages of the stuff.

"There were bits that James wrote about me that I either just hated or I agreed with but didn't want to admit. Other bits I felt were unfair. But we both got a chance to put our side over."

By all accounts, charm when competing isn't Cracknell's strong point. When I say 'all' accounts, I mean his too. Thinking back to his collapse at the end of the race, as they drew nearer to the Pole, he marvels at how nice Fogle and their team-mate Ed Coats were. "Would I have been so nice?" he says. "I don't think so."

"James thinks we could have done it quicker if he had stayed well," Fogle says. But he isn't convinced.

"It's debatable. We probably would have saved time, but he brought lots of other things to the team, to the dynamic, that helped us in other ways.

"The one thing that is true is that had it have been me that fell apart like he did, James would've been much more annoyed. But I know that's what James is like so I'd have expected it." The grin flashes again.

The race may have pushed them to their limits physically, but Fogle reckons the real battle is psychological. He experienced what he calls "extreme thoughts" while they were on their epic journey.

"You're skiing for 16 hours a day, you've got nothing to think about so, of course, you think about everything – what you've achieved, what you want to achieve, what you've got, what you want, what you've gained and what you've lost.

"You have very intense thoughts that you're convinced are right and then when you get back they slowly start to dissipate."

For Fogle the concerns were "probably about career and television" he says. And with that we arrive at the reason that Fogle, who as a boy didn't go to cubs or scouts and wasn't even sporty, has become a marathon-running adventurer. And, of course, why he wants to adventure with Cracknell.

"I'm sure that part of it is to test myself and prove to everyone that I can do it. And the more I've done it the more I love it," he says. "I probably am a little bit insecure. I've admitted that before. Or certainly I was."

The insecurity came from the way he entered the "media consciousness", as the posh pin-up of the original reality programme, Castaway, filmed in the Outer Hebrides on Taransay.

"I am still referred to as 'reality star Ben'," he says. "I don't mind it, but I'd hate that to define me for the rest of my life."

Definitions are tricky, it turns out, for both Fogle and Cracknell. They might be more resolved now, but both men have struggled with who they are and how they're perceived. For Fogle it was the Castaway hangover and for Cracknell it was how to move on from rowing. Their adventures, it seems, have helped.

"When we were at Hay (Book Festival] we were introduced as 'dreamboat hero adventurers'," says Fogle laughing. "I don't know that I'd use any of those three words. I'd probably describe us more as 'have-a-go apprentices'."

Cracknell agrees. "Hopefully what comes across is that it's genuinely something anyone can do," he says of their trek. "We're not any good at it, we just think, 'Right let's go for it'."

Fogle says that he and Cracknell are very clear about not treading on anyone's toes – they're not pretending to be something that they're not. But, with tell-tale ambitiousness, he reveals his aspirations.

"I guess my dream title would one day be explorer but that's reserved for the likes of Sir Ranulph Fiennes and the true heroes of adventure David Hempleman-Adams, Sir Robin Knox-Johnston, Sir Chris Bonington.

"I've accepted that I am an adventurer because I do go on adventures. It sits between traveller and explorer, but that's what one day I aspire to be."

Fogle says there's "no question" that he and Cracknell will undertake another adventure together, but at the moment he doesn't know what or where.

"We'll know when it comes along," he says. "And in fact my next adventure is that my wife is expecting a baby in December. It's very exciting. It's a nice end to the story, really." sm

n Race to the Pole, by Ben Fogle and James Cracknell, is published by Macmillan, priced £18.99. On Thin Ice begins on Sunday 28 June on BBC1 at 9pm.