Hurtling through the sea on a cold autumn day may not sound like a healthy pastime. Indeed, in many people's minds, dipping so much as a little toe into the British sea in October is akin to asking for a fatal dose of man flu. But surfing – especially at this time of year – can give the kind of health and fitness boost that makes an average trip to the gym look about as good for you as a bag of pork scratchings.
All those Sixties snaps of chilled-out hippies gliding along waves have fuelled the perception that surfing requires only a nonchalant stance and a pair of baggy shorts. But the reality is a little more taxing.
This month, I took lessons from someone who knows just how demanding the sport can be. Russell Winter, the only Briton to make it on to the World Championship Tour of the world's top 44 surfers, is now offering his expert advice to those wanting to improve their surfing.
"When you've been surfing for a couple of hours, you're completely knackered afterwards – you use your whole body, your arms, your legs, your core muscles: everything," Winter explains. He's not joking. After the first lesson, at Newquay's Towan beach, my limbs are so useless I can barely drag myself or my board back to the hotel.
In July and August, Britain's surfing capital can be a frightening cacophony of hen nights, stag dos and drunken teenagers, but Newquay is almost tranquil at this time of year. I stayed at the Carnmarth Hotel, whose peaceful rooms have large decked balconies that look out on to Fistral beach, where the town's biggest waves roll in.
But the peace and quiet is not the only reason to surf in October and November: the sea has also been warmed by the summer sun, the crowds of learners have gone away, and reliable ocean swells bring more waves rolling in. As winter and the prospect of weekends cooped up inside looms, autumn surfing offers a great chance to ensure that your time outdoors doesn't end with the school holidays. Also, as wetsuits get lighter, warmer and more flexible, there's no reason the elements should confine trips to the summer.
Today, an estimated 250,000 people in Britain go surfing every year. These are not all teenage dropouts, either: it is as common to see people paddling out on long boards far into retirement as it is to see someone turn up straight from work and wriggle into a wet suit or a toddler being pushed along on a board in the shallows.
For those less limber, surfing is about lining up the board with the shore, scrambling on and cruising into the beach. But Winter's way of surfing is not about posing on the odd wave, but thrashing, turning and twisting along every ripple that heads his way.
The lesson is serious – for a start, he's come equipped with a clipboard, a spreadsheet and a video camera – but he's also keen to see improvement.
I've been surfing for a few years with plenty of enthusiasm but very little skill, so I signed up to one of his coaching weekends in an attempt to improve. Winter's tips are specific: I'm not kicking my legs enough to catch up with the wave; my arms need to twist so I can head for the top of the breaking water; and I need to pump my heels and toes to go faster. Trying to remember all this often resulted in spectacular wipeouts and being pinned underwater, but just occasionally, it worked, and then Winter would be the first to say – whooping from the shore and later replaying the waves on his video.
The lessons were exhausting, but they had the desired effect. In the second session, at Fistral beach, I took a fair beating as wave after wave smashed over my head as I tried to make it beyond the breakers. But when I did catch one in, with half a carve turn along it as he'd coached, I could not remove the deranged grin from my face. By the end of the two days, it is fair to say – in the parlance of surfers – that I was stoked.
Being "stoked", the phenomenon of being deliriously happy after a spell in the water, is pretty widespread. It takes someone pretty stony-hearted not to smile after catching a wave. The mood-enhancing properties of surfing are so established that it is now being trialled as a way to combat depression. Patients are offered one-to-one surfing lessons in a pilot project paid for the Cornwall Primary Care Trust by the NHS.
Catching waves also helps to reduce stress. Lee Stanbury, author of The Complete Guide to Surf Fitness, says: "Surfing is a big-time stress-reliever, which is a huge benefit. Any exercise lowers stress, but you get a huge amount of endorphins released riding a wave – that's why it's so addictive. If you manage to go regularly, you'll have good fitness and core strength on top of that feeling."
Like thousands of others who love the sea but are stuck in the city, part of my motivation for surfing is escapism. If you are standing on a wave under a cloudless sky, meetings and deadlines are quickly forgotten. By the end of a weekend of intensive coaching, even my dreams were about standing on waves – a sure sign that all the exertion had made for a mentally relaxing weekend.
Tim Kevan, the co-author of Why Lawyers Should Surf, who left his job as a barrister to become a writer (and full-time surfer) in Devon, believes there is no sport that offers a better sense of wellbeing. "When you catch a wave, any cares or worries you have leave you and for that moment, you're at one with the world. It sounds terribly hippie, but it's true."