Cure or killer? The rewards – and very real risks – of the cold water plunge

Not so long ago, a cold plunge bath was used as a punishment for people considered insane. Now ice baths are feted by celebrities and social media influencers as a way to treat depression, lose weight and boost immunity. Yet immersion in cold water should be more widely recognised as a potentially lethal activity, according to academics, charities and even advocates of cold plunges.

“If this was people going for a gentle stroll, it would be fine,” said Professor Mike Tipton, who has researched cold water immersion for four decades. “Sixty per cent of deaths in cold water happen in the first minute of immersion. You’re taking a tropical animal and dropping it into 12C water – that’s not a risk-free activity.”

Last week, a coroner ruled that Kellie Poole died from an undiagnosed heart condition triggered by a cold water immersion therapy session in the River Goyt in Whaley Bridge, Derbyshire, in April 2022. The 39-year-old developed a sudden cardiac arrhythmia after entering the water, which was 10.7C .She complained of a headache then fell forward and later died.

Poole’s mother and Kevin O’Neill, who was leading the session, both said people offering cold water immersion as therapy should now be regulated. While the company running the session was not to blame for Poole’s death and could not have foreseen her adverse reaction,Peter Nieto, senior coroner for Derby and Derbyshire agreed, saying he would issue a prevention of future deaths report. The Department of Health and Social Care said it had no plans to regulate the activity.

Kellie Poole, who died after being submerged in cold water.
Kellie Poole, who died after being submerged in cold water. Photograph: Facebook

The American Heart Association has warned against cold therapy, and the British Heart Foundation (BHF) said people with heart conditions should check with medical professionals before such treatments.

Jo Whitmore, senior cardiac nurse at the BHF, said those with heart conditions are safest in water between 26C and 33C. “Entering very cold water can lead to a shock which can cause a faster heart rate, higher blood pressure and shortness of breath.” This, she added, could “lead to hypothermia and raise our stress hormone levels, increasing the risk of abnormal heart rhythms and possibly even cardiac arrest”.

From Hippocrates in Ancient Greece to Charles Darwin via Thomas Jefferson and Florence Nightingale, experts have advocated a cold plunge. “The Romans had the frigidarium alongside all the hot baths they had,” said Tipton.

Yet it has also been used as punishment. In the 19th century, it was used on those held in Ireland’s Limerick asylum, and the practice was outlawed after a man known as Danford died there in 1873 following “submersion in a cold plunge bath”.

I’ve had people describe it as like the high they used to get from clubbing, or the second hour in a marathon

Kate Rew, Outdoor Swimming Society

Wim Hof, the Dutch motivational speaker and self-styled Iceman, picked up the baton for cold water immersion, and Lewis Pugh completed an endurance swim across the north pole in 2007. Further stories of elite athletes such as Andy Murray and Jessica Ennis-Hill using ice baths added extra credibility.

The current trend emerged during the Covid lockdowns, Tipton said, adding that an open-water swimming group in Perranporth in Cornwall “went from 25 members to 1,000 over the course of the lockdown period”.

Fans tell of depression lifted, immune systems boosted, and feeling more awake and alive. With celebrities including Madonna and Holly Willoughby seen in ice baths, the trend is now so mainstream that TikTok’s lists #coldplunge as having 1.5 billion views, while consumer news websites rank the best cold plunge tubs of 2023, from £100 barrels to £13,000 plunge pools for the back garden – like a jacuzzi, but with an ice-maker.

Some organisations do highlight the risks. On Sunday, Surfers Against Sewage begins its Dip A Day in October campaign to raise money to protect the oceans, but they also publish prominent safety guidance.

The Outdoor Swimming Society, founded by journalist and author Kate Rew to promote swimming in rivers, lakes, lidos and seas, has published guides and warnings on its website. “Some people feel really high when they get into cold water,” she said. “I’ve had people describe it as like the high they used to get from clubbing, or the second hour in a marathon.

“Then the vast majority of people just find it cold, unpleasant and draining. We just don’t hear about these people very often.”

Rew, to her surprise, is a recent convert after a trip to Finland involved a quick dip in a frozen lake followed by a sauna. Now she has a cold metal bath in her back garden. “It’s the first thing I do when I wake up – skinny dipping in a tub,” said Rew, author of The Outdoor Swimmers’ Handbook.

“I check in with the sky and the weather, the wind in the trees, and I have this moment in a day which is a really focused joy. I don’t think I have the physiological thing that some people have that makes them addicted to cold. I like it just as a moment to breathe. And I do quite like being tough enough.

The Bluetits Chill Swimmers brave the cold in Southend.
The Bluetits Chill Swimmers brave the cold in Southend. Photograph: Penelope Barritt/Alamy

“There’s little scientific evidence to support the wellbeing benefits of cold water. There’s a dominant narrative that it’s very good for you to the extent that everyone should adopt it. But it’s not scientifically based. There isn’t much research except a lot of anecdotal evidence. So people should be liberated to follow their own inclinations.”

Tipton has reviewed scientific literature about cold water immersion and said there are hypotheses for some of the claimed effects – cold shock triggers the release of stress hormones, which make people feel alert. There are hypotheses that immersion might reduce inflammation, the way the body protects itself from infection, and people who do cold water therapies say they have fewer colds.

“But they’re only hypotheses – there’s been no properly randomised controlled trials,” Tipton said. Trials could isolate the effects of cold water from other things: exercise, floatation, overcoming a challenge or being outdoors. “Then you might be able to activate it in other ways.

Related: Coroner ‘concerned’ over lack of cold water immersion regulation after woman’s death

“I would not do anything that was seriously stressful without having a check-up that I was fit and healthy enough to do it,” said Tipton. “But it’s also how you go about it – the longer you spend in it, the greater the risk. It’s our estimation that if there are any benefits, they’re all accrued within a couple of minutes.”