It’s 2012 and I’m at Wimbledon chatting with Serena Williams. We’re recording an interview for BBC radio and she’s telling me about her new wristband which measures movement, heart rate, calories, even sleep quality. The technology is staggering. I find myself wondering if I should get one, despite the fact that only last week I bought myself a Garmin running watch that cost hundreds of pounds and offered many of the same features. I’m so absorbed by this conundrum, I realise that I’ve forgotten to listen to Serena, who stopped speaking several seconds ago and is now looking at me rather oddly. An increasingly awkward silence is filling the tiny interview room. I panic and accidentally ask her the same question again.

How had I got here? To a point where I was ignoring the greatest female tennis player in the world to indulge my mania for running tech? Cycling, fishing, golf… certain sports come with a love of equipment as standard. But running is meant to be simpler, isn’t it? The purest form of exercise. Just lace up your shoes and get out there. When Pheidippides made that dash from Marathon to Athens, he probably wasn’t wearing compression tights.

I only started running because I was plumping out in my mid-30s. I failed to reach the end of the street on my first-ever run – I set off too fast, paused for a wheeze outside a friend’s house, and ended up walking back home. But then I fell for it hard. I soon realised running was doing much more for me than just keeping the weight off. It gave me space – mental, emotional and physical. If I wanted to solve a nagging problem, I’d go for a run. If I was feeling tired, anxious, lethargic, I’d go for a run. The benefits were making themselves felt in every part of my life. I was soon doing it every day, often twice.

Facebook Twitter Pinterest Keep on running: with four-time Ironman triathlon world champion Chrissie Wellington. Photograph: Stuart Holmes

Within a few years, I was cheerfully signing up for ultra marathons and triathlons (I once attempted one of each on the same weekend). I discovered I was living in a golden age of the runner. Back in the 80s, when people went out for a jog, all you needed was a tracksuit – accessorised, perhaps, with a headband and matching sweatbands. The only piece of tech you required was a Walkman to keep you moving to the beat of “Eye of the Tiger”. But now that “jogging” has transformed into the more serious pursuit of “running”, there was endless kit to be had. The tech crept into my life in increments. It started with the quest for the perfect pair of shoes. Then came the base layers – top and tights – that promised to be “injury reducing, temperature controlling and moisture managing”. Clearly these were completely vital. They were also £90 a pop, but hey – I’d get added value with each run. Next, socks. Another £40, but that’s money well spent when you consider that the ones I chose were “not only the result of tireless research work, they were also the subject of a doctoral thesis”.

You’d think the gadgetry would make my runs more enjoyable. But instead they were becoming more stressful

Most weeks I’d emerge from a running shop armed with another must-have accessory. Sure, I was setting myself tougher and tougher running goals. But did I really need a hydration backpack to help me achieve them? Or hi-vis gloves and a £400 GPS watch? My transformation from “someone who went for a run” to “runner” was accompanied by the kind of monomania that characterises both Olympic athletes and middle-aged men in Lycra. My growing collection of running-related paraphernalia was fast becoming obscene.

It’s a generally accepted truth that men love to feed our sporting hobbies with exorbitant, extravagant equipment: and we love to talk about our newest discoveries and acquisitions. As a sports reporter in regular encounters with professional athletes I suffered acutely. I think it was one of the Brownlee brothers – the world champion triathletes – who told me about sweat analysis and an isotonic drink which exactly replicates the minerals lost during exercise. I spent ages trying (and eventually failing) to find somewhere to create the same for me. But I did have my gait analysed in a lab in Oxford to check for minuscule deviations from the ideal which might lead to a niggle. As a result, my orthotics were custom made in Canada. And that Nike band Serena Williams talked about? I bought one, of course. After all, who doesn’t want to have something in common with Serena?

You’d think all this gadgetry would be making my runs more enjoyable. But instead they were becoming more stressful. Dressed in my lurid gear, I’d stand in the middle of the road waiting for my watch to find a satellite signal. Even during a supposedly easy run, I’d check it every few minutes to discover how fast I was going – and all too frequently would end up berating myself mid-run. In the end, as I wandered around outside my front door scowling at London’s pesky, signal-obstructing buildings while impatiently waving my wrist at the clouds, I would be secretly dreading the hour or so that lay ahead of me.

Facebook Twitter Pinterest On your marks: all kitted up and ready to go. Photograph: Richard Saker/The Observer

As for the races, every marathon became nothing more than a failure to achieve my ultimate goal – to finish in under three hours. Gone were the days when running 26.2 miles gave me any sense of achievement. It took me a while to work out that running stops being pleasurable – and stops being a release of tension, stops being an escape, an act of discovery and self-discovery – if you’re constantly stressing about how fast you’re travelling, what you’re wearing, what your heart rate is doing.

Proper analysis is crucial for elite athletes. But I had lost the most elemental reason for my run – the sense of pleasure and diversion. Running can be simple and child-like and brilliant. The watch and the gear were keeping me away from that. They had to go. For a while they festered in the back of a cupboard. Then came a flash of endorphin-fuelled clarity after a fell run, and I bundled them all up and gave them to a local charity shop.

Fast forward to a beautiful spring morning near Keswick, cresting the top of a fell and suddenly, unfolding into my gaze, the sublime radiance of the Lake District. All of England seemed to lie below, and I forgot about my aching thighs, sniffed the unpolluted air and enjoyed the sensation of soft earth under my feet. I realised, in that moment, there was nowhere else I’d rather be, and nothing else I’d rather be doing. I’m no expert, but isn’t that what they call mindfulness?

I once interviewed a sports psychologist with a deeply impressive client list. He quoted Leonardo da Vinci: “Simplicity,” he told me. “Simplicity is the ultimate sophistication.”

Don’t Stop Me Now: 26.2 Tales of a Runner’s Obsession by Vassos Alexander (Bloomsbury, £12.99). To order a copy for £10.39, go to bookshop.theguardian.com