It's minus 17 degrees in Gorky Park, Moscow, and I quicken my pace along the snow-crusted paths. Since I started to run, there has been a knife attack and murder in a hotel room and the killer is preparing to make a suicidal leap from a bridge.
It's adrenaline-pumping stuff, but – though I'm in spy thriller heartland here in the Russian capital – the whole thing is taking place in my head or, perhaps more accurately, via my headphones. The Fear Index, a thoughtful thriller from former Observer journalist Robert Harris, is the latest audiobook to take my mind off the slog of training for a Siberian half-marathon in temperatures that should keep any respectable weedy Englishwoman indoors on the sofa.
Reluctantly leaving our flat to pace the embankment of the frozen Moskva river three or four times a week, I've listened gratefully to Harris's tale of hedge funds and rather too clever artificial intelligence and to much else besides: Simon Sebag Montefiore's Young Stalin; The Story of English in 100 Words by David Crystal; Gillian Tett's history of the banking crisis, Fool's Gold; favourite bits of Jane Austen.
It's all a bit surreal. Living in Moscow (my partner is working here for two years) is odd enough anyway, without David Crystal suddenly whispering "arse – an impolite word" in your ear as you jog past the Gotham-style Stalinist skyscraper of Moscow State University. But since I had the bonkers idea of signing up for a half-marathon held annually on the frozen surface of Lake Baikal, it's the calm and diverting rhythm of audiobooks that has persuaded me to train on snow and ice in temperatures dipping below 20 degrees.
Typically, iPod-toting runners opt for a musical soundtrack – running websites are full of threads recommending pumping sounds that will speed Lycra-clad sportsmen and women to new "personal best" times. But as the spring marathon and half-marathon season approaches, many of those pacing the pavements are not finely tuned super specimens, but ordinary, rather unfit people seeking a bit of free, adaptable exercise with a goal to push them on.
It is we amateur runners who are likeliest to turn to audiobooks as a training accompaniment, I suspect. Far from wanting to "listen to our breathing" to achieve an optimum split time, we'd rather drown it out with something more interesting that will distract our minds from the miles of unrun road ahead. As I found with The Fear Index, a cliffhanging chapter ending will force the most reluctant runner into his or her trainers again, not for the fun of training but simply to find out what happens next.
The trend for running to words has been noted by Audible, the UK's largest provider of downloadable books, and the company is keen to pursue the issue. "Running and exercising while listening to audiobooks is something we're aware of," says a spokeswoman. "In fact, one of the biggest spikes in people visiting the site was when Stephen Fry announced on Top Gear that his huge weight loss was due to walking around London listening to audiobooks."
Fry, much in demand as the voice of audiobooks, including the unabridged Harry Potter series, claimed to have shed six stone striding along to the unlikely beat of Trollope, Dostoevsky and Agatha Christie.
Readers of the Runner's World website have started to share audiobook tips as well as music recommendations. Thrillers and mysteries are popular – "Read Agatha Christie's And Then There Were None and count down the miles per person bumped off," advises one site member – together with "lose yourself" epics such as Memoirs of a Geisha. Some choices prove problematic: comedy can lead to sudden bursts of laughter, alarming passers-by, whileone runner's decision to read an audiobook on the history of Cadbury's was "a disaster – it just made me want to eat chocolate all the time".
Metaphor is more important than metabolism, another argues: "I have one audiobook of Richard Burton reading poetry – it's fab, but not sure it will make me run faster."
For the audiobook runner, I don't believe speed is of the essence. So much of running is in your head, and since my head is usually trying to shout: "Stop! – this is boring/knackering/cold", I'd rather fill it with something entertaining, improving, or a mixture of both, knowing that, especially on the deserted Moskva embankment, I can give the words my full attention. I still have many of Crystal's 100 words rattling in my head – fopdoodle, chattels and matrix – and was bewitched by Sebag Montefiore's account of Stalin's path from cobbler's son to revolutionary via poetry and a brutal seminary.
Last month, I donned my earphones, together with running spikes, balaclava and a daunting number of thermal layers, and ran across the snowy surface of Baikal, the world's deepest lake, where the spring ice is thick enough to support a monster truck – not to mention 130 runners from 20 countries.
Almost certainly uniquely in the lake's multimillion-year history, I trotted across it listening to John Mortimer's Rumpole of the Bailey. It is, I'll admit, a little odd to combine the Siberian wilderness with an ageing barrister's account of life at the Bar, and with She Who Must Be Obeyed but, over two hours 25 minutes and 13.1 miles of sheer white emptiness, the audiobook got me through.
Lucy Ward is a freelance journalist based in Moscow
