When I was 17, my rowing coach announced that taking a day off was unnecessary. That one time of the week that I left school at 4pm and watched Neighbours was now gone. I think that’s probably why, when I gave up rowing, I stopped doing any exercise at all. I’d had enough. Exercise for me equated to diehard commitment and someone shouting at me all the time. So I did nothing. Which in retrospect was a bad idea, because there were times in my life – getting RSI when I tried to write a book while holding down a full-time job or having a baby and getting swamped by anxiety – when exercise would have helped enormously.

It was when I had come out of the baby years, moved to a new area, but worked from home, that I felt the pull to be part of a team again. But I didn’t know how or in what sport – there was no way I was going back to rowing.

There are plenty of “back to…” sessions for various sports – hockey, football, lacrosse – but having never played any of these, I was daunted. Then one day a neighbour knocked looking for a sub for her netball league team. I’d been OK at netball at school, so I said I’d do it. It was during that game I realised all the latent competitiveness that had pushed me at school to become a junior world rowing champion, was still very much there. And when I got rid of it, through sport, it took the pressure off other areas of my life.

A friend of mine went back to lacrosse after her therapist told her competitive sport was excellent for building up emotional resilience (the ability to cope with stressful situations, challenges and adversity). That was exactly why, without consciously knowing it at the time, I took up rowing as a teenager. It was a counterweight to the cliquey, results-focused, all-girls school I went to – where the headmistress berated us for the “sparkling array of Bs and Cs” in our exam results. It was competitive, but in a different way. I discovered that popularity didn’t rely on the whims of the clique, but on the ability to work together to shift the boat. By the time I made it to the GB junior squad, that resilience was more important than ever, because the pressure ramped up, there were blood tests to check performance levels, our heart rate monitors were set to beep if we weren’t working hard enough, people’s blisters went down to the bone and one time I remember being too exhausted to get up off the floor to go home.

I am naturally competitive. And while this is good when it comes to sport, it has the downside of building up adrenaline in areas of life where it isn’t helpful. It’s almost impossible to relax, because I feel that everything could be done better. But as I started playing netball, I realised that each week it pulled the plug on the pockets of stress that had built up in my everyday adult life.

Being an author is a brilliant job, but working in isolation does get lonely. The main communication with the publisher or agent is around the time of book publication or handing in the first draft. For much of the year it’s tumbleweed – just you and your characters who are in essence extensions of yourself or versions of how your own brain would tackle a problem were you, say, a murderer.

Working alone and watching other people’s careers via social media can lead the best of us to paranoia. Staring at a screen all day wreaks havoc with the neck and back. And, while coming up with the ideas is great, when you’re stuck with a blank piece of paper or pages of revisions willing a solution, it’s the ultimate frustration; it’s there when you’re eating, sleeping, walking to pick up your kid from school, watching TV. There’s no escape.

But there is a break now for me that comes from picking two of my teammates up every Tuesday evening and driving to a netball game. It’s half an hour on the court where the only object of interest is the ball. And, as a defence player, stopping the other people from getting it. It sounds ridiculous, but I can go to sleep replaying the feeling of a good interception (but equally lie there wide-awake lamenting a terrible pass or game-losing penalty). We play against people who are much better than us and a few who are much worse. There are girls straight out of uni, top of their squad, who moan about being as old as 25. Women in their 40s and 50s who have to bring their children with them, setting them up on iPads because their partner is out or there’s no babysitter – and that weekly game is as important to them, for whatever reason, as it is to me.

This is where friendships differ from the norm. In our league, we don’t know each other’s backstories. In some of the opposing teams, who I’ve played against for years, I don’t even know the names of the players. But we say hello. We congratulate each other. I know how they run, catch, pass. I know their tricks; I know if they get angry when marked too closely or happily barge me out the way with the whole force of their body. On my team, we don’t have jobs in common or kids the same age, as one might usually with friendships, nor have we met each other’s families. But we are bonded by a shared desire to play and to win (which often we don’t). We train together. We celebrate our wins or moan about losing or bitch about how we were wronged on court together. And over the years this bunch of strangers have become my friends. The journey there in the car is 10 minutes of life-problem moaning, but on the way home, after the game, everything feels a little bit better.

It made me remember the things I loved about being a rower at 17; that your team were the people you trusted to want something as much as you. You didn’t have to even like each other, but you had to respect their talent, their commitment and their effort. The sporting friendship is one based on knowing that in the pouring rain, freezing cold, or ferocious, sweating heat, you all show up, because it makes life better. And then you go home to your normal life.

Where the Junior Worlds was my ultimate goal as a teenager, what’s so great about my weekly netball game now is that it doesn’t matter. It’s competition for competition’s sake. It goes round in an endless loop of the same teams and the same players – you can beat a team one week and lose against them the next. You can walk away if someone shouts at you.

This is not the cliché of school sporting types – these adult teams are made up of strong, determined women of varying ages, shapes, sizes and fitness who are there simply to compete in a game they love with people they respect. It’s something I thought I would never do again and in the grand scheme of things it’s a very small change – less than an hour a week – but it has categorically improved my life, perhaps even built up my inner strength.

OK, so I still cried (in the John Lewis underwear department) when I got an email to say I needed to rewrite the book I had spent a year working on. But that evening I went to play netball. I started the game in a really bad mood – apologies to whoever I was marking – but, as it went on, I actually felt my emotional state change. Netball is so fast and strategic that there’s no time to think of anything other than where the ball or your opposing player is. In essence, the game gave my brain a half-hour holiday to focus on something other than the rubbish work news, while behind the scenes processing it and decatastrophising.

On top of that, there was the actual physical release of the exercise, burning through the adrenaline of the shock and dispelling the cortisol from the stress. By the end of the game, I was still gutted, but I had some perspective. I can’t say whether I was more resilient than if I hadn’t taken up netball. But what I can say is that the game itself, and the act of playing in that team, allowed me to escape the realities of life for enough time that I could calm down and rationalise, so what felt devastating before was less so after. Which I suppose is exactly what emotional resilience means.

The Fifth Guest by Jenny Knight is published by HQ at £8.99. Buy it for £8.36 from guardianbookshop.com