Jessica Hepburn at Everest Base Camp

THIS is a story of how castaways washed up on a deserted beach helped a woman with no interest in sport run the London Marathon, swim the English Channel and conquer Mount Everest.

Jessica Hepburn is the only woman in the world to complete those three challenges ­and she has another record to add to her roll of honour: she is possibly the only person in the world to have completed all three physical challenges while listening to every episode of Radio Four’s Desert Island Discs.

The results can be found between the pages of Jessica’s latest book, Save Me From the Waves, which explains how more than 3,000 episodes of an individual choosing eight songs and a luxury item not only helped Jessica take on extraordinary physical demands, but also helped her come to terms with a personal situation: the failure of 11 rounds of IVF to become pregnant, and the break-up of a relationship with the man she had hoped to become a parent with.

Jessica, who grew up in South End Green, says music and memory makes DID: “That is why it has and will always endure,” she explains.

“At its heart it’s about family and friends. The ones we have and find, but also the ones we’ve lost or will never have; all of whom make us who we are.”

Soothed by the choices made by guests, Jessica found an outlet for pain and worry.

“I made the decision to take on the challenge of listening to every episode of Desert Island Discs while walking up 8,848 metres,” she recalls.

This is her third book, her previous two dealing with IVF and motherhood.

“They have all been personal, but this is more literary, more oblique and more intellectually challenging because of the music,” she says.

“I write alternative adventure stories but this isn’t your usual Everest summit story. This is about mountains and music – and much more about music than mountains.

“Music brings me joy – more than running, climbing and swimming. Of course those exercises are important – but they are, in a way, like self-harm.”

We learn of long strides up Parliament Hill, Lauren Laverne in her headphones, as training gets under way.

But as the reader discovers, this is no straightforward, personal development yarn.

“I wanted to write it in a friendly way and then punch the reader in the gut,” she says.

Preparing to take on the English Channel

The narrative arc explains her background, the trials of IVF, and her motivation for setting out on three hardcore tasks.

And taking on Everest was not just about a physically demanding feat: as she explains, she was hit by two awful experiences. She broke her leg badly on her descent, which put her life at risk – and was also assaulted, a situation that she briefly mentions but doesn’t expand on, due to the pain.

“I broke my leg in the death zone and if the weather had not been clement I would have died there,” she says.

“And then there was additional trauma, that I will not go into here. The words felt dangerous to me.”

Despite the trauma, climbing the world’s highest peak leaves a long-term sense of achievement.

“The adventure has changed my life for the better,” she says. “When I started training for it, there was a darkness in my life from the 11 rounds of IVF, losing the love of my life in difficult circumstances, the trauma on the mountain. It can feel really dark but I wouldn’t change it for anything. I can use it as my superpower.”

Facing up to a challenge is an important learning experience, she says. “There is a real mistake in life,” she says.

“When something difficult happens, there can a be a linear path out of it, but my view is that we have challenges we have to face. Disruptions in life, and the effort to overcome them, is what it simply means to be human. Our job is how we use situations to train ourselves  to create one thing good.”

Being honest about her experience with IVF, about splitting up with her partner, moving back into her mother’s house, and facing a personal crisis, means Jessica has an open approach to sharing.

“My three books have been personal,” she says, “I am used to that aspect. I went through this long IVF journey in secret. I was running the Lyric Theatre for 10 years, and all the time I had this secret life, chasing motherhood. I wrote about it – and that was a big decision. I was brutally honest and I realised the depths and despair. When you tell your darkest secrets, people recognise authenticity, honesty – and they say, that’s me, too.”

Her latest work is what she calls an adventure story. “It was about how I solved a problem,” she says.

Writing it all down has helped her work out in her open mind what she has been through, she adds.

Jessica is now a trustee of the national charity Fertility Network UK where she brings to bear her experience.

“You have to become your own doctor,” she says. “You have to take responsibility. IVF seems to work differently for everyone – there is a lot about reproductive science that is unknown. It means you end up becoming an expert – you trust your instincts and the research you have done.

“It is a disease of the body and of the mind. It isn’t just about your body not getting pregnant. The worst part is what it does to your head. It throws up so many awful feelings – that you are not somehow a ‘proper’ woman – there are a lot of emotions to handle.”

She adds that her achievements have shown her that it is important not to let others tell you what your limits are.

“I hated exercise as a child. I still hate exercise. It taught me that the labels we are given are unhelpful and can hold you back. I discovered that I am cut out for big physical and mental challenges. Mentally I am stronger. I am the first woman to have completed these three big challenges, and on the mental side, I am as tough as it goes. I got through 11 rounds of IVF – that is a big endurance feat, as is writing a book about it.”

She urges goal-setting as a tool to get you up and out. “We have a stereotypical idea but an adventure could be listening to every episode of a radio show,” she says.

“When you are starting your quest for an adventure, choose something just beyond your grasp – so you can reach it, but with effort. Exercise can be hard to do, but you always have to remember life feels better after you have done it.

“Above all, I am an advocate of the idea that you have one life, you are just a tiny speck in this universe – so live the most exciting life you can and do some good with it.”

She has one ambition, post-Everest, marathons and channel swimming.

“I would love to go on the Desert Island Discs,” she admits. “I am a superfan. I still haven’t chosen my songs, but I am closer – after all, I have done the research.”

• Save Me From The Waves. By Jessica Hepburn, Aurum, £17.99