‘Wild swimming’: Healthful activity or high-risk recreation?

October 4, 2022

If you happen to know an outdoor or wild swimmer—a swimmer who prefers rivers and lakes to heated pools—you are part of a growing subculture, reports The Guardian.

 The Outdoor Swimming Society (OSS) had 300 members when it was launched in 2006; now it has 175,000 across its social media sites and one million visitors annually to its website. The society recently polled its members on why they swim outdoors: 94% responded that the main reason was “joy” — reporting that they feel happier and less stressed after a dip.

And this, apparently, is te perfect time of year to make the leap: “Have you heard of the Pareto principle?” asks Dr. Mark Harper, an anesthesiologist, researcher, and author of “Chill: The Cold Water Swim Cure.

He explains, “It’s where 20% of the effort produces 80% of the results. So we’re in that beautiful time now where, if the temperature is between 15 and 20C, you’re probably getting 80% of the benefits of the cold water for just 20% of the effort.”

Such testimonies are anecdotal, of course, and even the OSS acknowledges the society is “a borderline cult built on enthusiasm.” And this remains a recurring question mark for wild swimming and cold-water immersion: despite all the evangelical claims made by fans, there has so far been minimal scientific evidence to confirm them. That’s not to say that the benefits do not exist; only that there have not been sufficient, rigorous clinical trials to prove them either way.

That, though, is starting to change, and in the past month academic papers have been coming thick and fast. Harper was part of a team that looked into whether sea swimming could be “a novel intervention for depression and anxiety”. The study enrolled 53 people—47 women, five men, one non-binary—in an eight-session swimming course and tracked their wellbeing by questionnaire. Harper says there was a notable upturn in many of the participants’ mental health, and he is particularly heartened by the fact that, three months later, 80% were still swimming outdoors, reporting that they found the activity helpful.

Harper also worked on a project this year with frontline NHS workers to see if outdoor swimming could improve symptoms of stress and work-related burnout. Participants swam in an outdoor pool in London or in the sea in Cornwall—and overall reported a 14.8% increase in wellbeing scores after six weeks.

Before you go and hurl yourself in the nearest lake, however, there were words of caution in the British Journal of Sports Medicine. There, Mike Tipton, professor of human and applied physiology and a global expert on extreme environments, points out there was a 52% swell in HM Coastguard callouts between 2018 and 2021 connected to open-water swimming. There’s also been a 79% increase in deaths—from 34 to 61 in the U.K.

Tipton was encouraged to publish the paper after seeing the BBC reality series, Freeze the Fear with Wim Hof, about the Dutch extreme athlete who has spent more than three hours in direct, full-body contact with ice. “Although there was a safety message at the start, if you watch those programs you would be inclined to go and put yourself into cold water,” says Tipton. “So we thought there was some need for just saying: ‘Look, we are a tropical animal and this is one of the largest stresses you can place upon the body.’ We’re not trying to stop people doing things; we’re not the Fun Police. But there are ways of maximizing the potential benefits and minimizing the risks.”

Here, Tipton and Harper are in full agreement. If you are contemplating dipping a toe into outdoor swimming, especially this winter, you should have a medical assessment first. Start in a spot with lifeguards and enter the water gradually: Resist the urge to jump, dive, cannonball. Spend less than ten minutes in the water, even if you don’t feel cold. From personal experience of outdoor swimming, this is a key point: I’ve had dips where I’ve timed it right and felt giddy all day, and others where I’ve spent too long in the water and my teeth are still chattering two hours later.

Tipton and Harper are also both clear that more research needs to be done before we assign transformative powers to outdoor swimming. “I can recognize the anecdotal responses—what we don’t know about going open-water swimming, though, is what the active ingredient is,” says Tipton. “So when you go open-water swimming you meet up with friends, you go into a beautiful environment, you’re floating, you’re supported by the water, you do some exercise, you do get cold, you come out and you have cake.

“There are so many other factors,” Tipton goes on, “but we don’t know which one is actually responsible for any claimed beneficial effects.”

Research contact: @guardian