I have a friend who claims to have completely cured her arthritis by swimming in the sea, whatever the weather. Her pains completely disappeared, and she swore that it was because she immersed herself regularly in freezing water. I recently saw British athlete Mo Farah and Portuguese footballer Cristiano Ronaldo do something similar on TV, sitting in a bath of ice so that they could recover quickly and remain toned and fit. I have read that ice baths bring so much benefit to fitness: apparently, regular immersion in ice eases sore and aching muscles, helps the central nervous system, limits the body’s inflammatory response.

I have to confess, I like the heat more than cold: saunas, sunshine, jacuzzi baths, hot water bottles. I prefer to immerse myself in warmth, although I’m sure there are no benefits, other than that lovely feeling of sumptuous luxury and pampering, the sense of indulging in something that makes me feel good.

Like a relaxing hot stones massage, a glass of wine or two, the company and conversation of beloved friends and family stretching into the early hours of the morning, immersing oneself in something to the exclusion of everything else is really therapeutic and brings benefits, both to physical or mental health and wellbeing.

So, what if it is the same in writing? I know so many writers who claim they can’t get started on a new novel, or they can’t continue once started: they run out of impetus and enthusiasm, or they run out of time.

Then again, I know so many writers who don’t: an idea grabs them and they run with it and keep going and going. So begins the writer’s immersion technique.

I am one of those people who begins a project and, if it grabs me, I can immerse myself in it. I don’t mean doing labours of necessity like domestic chores, gardening or hoovering, things I have to do but they are, honestly, only done because if I don’t do them, we’ll starve or the house will collapse. I mean, when something really grabs the interest, it’s hard to put it down. When I write a novel, the computer is like a magnet and I can’t pull myself away. I have to immerse myself in the characters and their escapades until I’ve finished, then I go back and edit over and over.

But my last two novels have been, even more, about complete and utter immersion. I wrote one in six weeks not long ago: the three characters just wouldn’t leave me alone. It was the first time I’d worked for seven days a week, ten hours a day, since I was teaching theatre and that was complete immersion too. It was exhausting, writing non-stop, I’ll admit – 100,000 words in six weeks, or forty-two days. But the novel really grabbed me and I missed meals and TV and a social life to write it. No, it was worse that that: people would speak to me and I wouldn’t reply – I didn’t hear, I was so involved in what I was doing, nothing external had a chance. The characters woke me up in the night to debate their next move; writing their antics on the page came out faster than my fingers could type and I just couldn’t walk away from it all. My shoulders were knotted, my eyes blurred, but I had to keep going. And now it’s finished, I’m pleased with it: readers can decide for themselves if they like it when it comes out in winter.  As yet I only have a working title… three very different women, a staycation or two…

Then there’s the ghost novel I am writing, which involves lots of research. Immersion again – more missed meals, more unresponsive conversation, more typing and reading and rubbing of sore eyes from dawn to midnight. Immersion is such good fun and, like a good book, it’s unputdownable, although it’s also antisocial, and the level of absorption can’t really go on indefinitely or there would be consequences to things like marriage and friendships and cats being fed.

But, like Mo and Ronaldo’s ice-filled bath, it’s very refreshing and a wonderfully intense way to work, a therapy that has the benefits of a whole rush of ideas and enthusiasm, and leaves one feeling like a happy kid at the centre of their own birthday party.

Being involved in a project to the exclusion of everything else is great fun; it brings results in terms of output and productivity. I have a book that I’m pleased with, two, in fact, so I can give myself permission to take a breather now. Like a sprint, it is fast and full-on, then afterwards time is needed to recuperate and become fresh again, ready for the next full pelt.

But immersion can only be a temporary and sporadic thing. Writing can be a selfish occupation: I’ve even been at social events where my head has been plotting the next move when it should have been fully attentive to other people. And selfishness isn’t good, nor is obsessive devotion to just one thing. I’m all for immersive writing – it works for me and as a writer, you have to do just that, gauge what works for you and follow your own path. We shouldn’t seek to be the same as each other or influence others to tread the same road just because it works well for us. But now it’s time to let go, walk away, to do something else for a week or two, chill out a bit and get a life.

Because, as we all know, the benefit of time away, relaxation and mental stillness will bring in new ideas, new plots, new characters.

Then I can start all over again…