Why cold water swimming might be doing you more harm than good

In evolutionary terms, “We’re a tropical animal, we want to be naked in air at about 28 degrees Celsius,” says Tipton. “If you take a person and plunge them into cold water you’ll get a significant physiological response.”

Research in the aftermath of the sinking of the Titanic led to a widespread understanding of the dangers of cold-water immersion with regard to hypothermia. Now it is understood that the first minute of immersion holds the most significant danger. “That moment where you gasp and have uncontrollable ventilation, there’s a high workload put on your heart,” says Tipton.

The sudden cooling of the skin leads to a cooling of the superficial nerves and muscles, which can leave you physically incapacitated within 10 to 20 minutes. “And all of this has occurred before you become hypothermic. There’s absolutely no doubt that going into cold water is amongst the greatest stresses to which you can expose the human body.”

You can habituate to the cold-water shock response, which will make the experience safer and less likely to result in cardiac problems or drowning. But Tipton says: “Going into cold water as a precursor for drowning or cardiac problems is well established with definitive research.”

Anecdotal

The benefits, meanwhile, are mostly anecdotal. “The definitive studies are yet to be done,” he says. “There are hypotheses, speculation and anecdotes. But research just hasn’t been done. No one has isolated cold from all the other things that happen when you go into the water like exercise, socialising and being in nature.”

And yet humans have long evangelised the benefits of a chilled plunge. There’s nothing particularly new about Hof and his followers; from the Romans through to Thomas Jefferson and Charles Darwin, cold exposure has had its enthusiasts.

The best explanation for that euphoric rush one feels after cold-water immersion is that the cold shock response releases hormones that are alerting and arousing as part of the fight or flight response. “It’s no surprise that people who do it say it makes them alert and sets them up for the day,” says Tipton. “It’s the stress response.”

It is a sensation I experienced last month. On a sunny September morning, I jumped (or rather eased myself) into a swimming pond in the Wiltshire countryside. The water was a brisk but not too spine-shattering 15 degrees. I swam two lengths, and then I got out, feeling intensely, almost viscerally alert. Shortly afterwards, I did two more lengths, and posed for a photo with my friends.

Afterwards at lunch, wearing dry clothes and a fluffy jumper, I started to feel not quite myself. Withdrawn, quiet and, most of all, cold. I felt silly compared to my hardier friends who’d stayed in longer; but as soon as I spoke up, they bundled me in extra layers and plied me with hot drinks.

I wondered whether the reason was not only because I am a relative cold-water novice, but also because of my lack of body fat.

When I tell Tipton about my experience, he isn’t surprised by my reaction.

While fat doesn’t protect from the initial responses, because the cold receptors that initiate that response are just 0.18mm below the surface of the skin and lay over the top of subcutaneous fat, that subcutaneous fat does start to help with the cooling of the deeper tissues.

“It has the same thermal character as cork. So it’s quite a good insulator.”

A price not worth paying

What I experienced was a phenomenon called “afterdrop”, whereby even after you leave the water, the cold front keeps moving into the body and deep body temperature starts to fall.

“It’s why people can be at their coldest 15 minutes after they leave the water,” explains Tipton. “If you don’t institute pretty aggressive rewarming procedures, you can be cold for a long while.”

It’s not the first time I’ve failed to warm to cold-water swimming. Personally, I have found that after the initial rush comes a price not worth paying. A cold-water therapy trip two years ago left me with a two-week cold.

“The evidence shows that if you get too cold it actually diminishes your immune system,” says Tipton.

And yet – full disclosure – I have interviewed the cold water guru Wim Hof in the past and found some of what he said sensible. UK homes are kept 4 degrees warmer than in 1970. Modern, cosy lives mean that our thermoregulation, metabolism and cardiovascular systems have become sluggish. That we’ve become sedentary and thermostatic is also a point Tipton agrees with.

“I do have some sympathy with Wim Hof in that respect, but I have less sympathy with him shouting into a camera that everyone should be going into the water and anyone can do this. Because not everyone can.”

For people with pre-existing conditions and comorbidities, cold-water immersion is a dangerous thing. Guidance from the Association of Chartered Physiotherapists in Cardiac Rehabilitation suggests that water temperatures between 26 and 33 degrees are safest for people with heart conditions.

One size fits all?

In the UK, the water temperatures in natural environments are roughly between 10 and 28 degrees in the summer, falling to between 0 and 7C in the winter. So swimming in a heated pool is likely to be a safer option.

People expect Kate Rew, as the founder of the Outdoor Swimming Society, to be a cold water enthusiast. Somewhat surprisingly, she is not.

“I have never enjoyed winter swimming,” Rew admits. “I’m really rubbish with the cold, so I have full sympathy with people who’ve not got on board with this trend.”

Her worry is that cold-water immersion has been sold as a one-size-fits-all activity, when really there is a huge range of individual variation, from body mass through to pre-existing conditions.

“It’s been quite frustrating watching the dominant narrative of the last couple of years be that cold water is good for your mental health.

“There have been lots of very bold wellness statements that aren’t backed up by science. The truth is we’re not all the same in how we respond to cold. But it’s a narrative that makes people think they should be doing it and it should be good for them.”

Experience has taught her that her sweet spot is about one to two minutes – immediately followed by a sauna.

“When I do it that way, I have a lovely time. But I’ve spent too long trying to become a winter swimmer and sludging up and down wondering why I’m still suffering, hours later.”

Her main piece of advice is that people should follow what feels right to them.

“If people get a buzz from sitting in cold water, that’s great. But I do wonder why we keep turning to gurus to tell us what to do. That’s where people lose track of how it really feels for them.”

In the tragic case of Kellie Poole, her cardiac condition was undiagnosed. This is why Tipton recommends that people should undertake a health check to make sure they are medically fit and healthy before taking part in cold-water swimming.

“This is a significant challenge to human physiology. If you’re going to undertake it, you don’t undertake it lightly.”

He adds: “I’ve got no problem with people wanting to do it. But it does need to be done in a safe way with experienced people, preferably in a lifeguarded situation.”

And even if all the right precautions have been taken, Tipton thinks that staying in the water any longer than two minutes is unnecessary. “Most of the benefits people report come from the first two minutes.

“The more you overstay your welcome, the more dangerous it becomes.”

The Telegraph London