Can cold water therapy really help you chill out?

Lady Gaga, Kim Kardashian, Harry Styles and Joe Rogan have all taken the plunge. Over the past few years, social media posts featuring celebs and influencers submerged in tubs filled with ice have snowballed, giving rise to a cool new wellness trend: cold water therapy. Proponents tout benefits ranging from stress and pain relief to improved athletic performance and mental clarity.  

While cold therapy may be ever-growing in popularity right now — global sales of cold plunge pools are expected to exceed $550 million US by 2031 — the practice has been around for ages. The ancient Egyptians used cold to treat injuries as early as 2500 BC, and British physician Dr. James Arnott used cryosurgery to freeze cancerous tumours in the mid-1800s. 

Current research into the effects of cold therapy, however, is limited, as science races to catch up with the social media algorithms. For those looking to dip a toe into cold exposure therapy, safety is more important than icy selfies. Talk to your doctor if you have existing cardiovascular issues. Test the cool waters at home, then when you're ready to experience a cold plunge outdoors never go alone, especially in bodies of water you're unfamiliar with. Instead look for an experienced practitioner to guide you through the experience.

As more people embrace cold water therapy for its potential benefits, its growing popularity has piqued the interest of experts across diverse fields. We reached out to a researcher, an Olympian, and other advocates to learn more about why cold water therapy has become so popular.

It may help you chill 

Stress levels are on the rise in Canada, with 33 per cent of us reporting we feel stressed regularly (up from 17 per cent from before the pandemic). Could cold plunging help us cope? 

Vancouver-based pain coach David Gu thinks it can. "Our stress response system is the same one that we had 300,000 years ago," he said. "Our nervous system doesn't know how to differentiate between an actual imminent threat, like a sabre-toothed tiger jumping out at us, and something that we perceive as a threat nowadays — it could be a chore list, it could be a toxic relationship, it can be the person who cuts you off in traffic," he said. "We're in this constant state of stress, which is taking away from our ability to function optimally."

When our bodies are suddenly immersed in cold water, the "cold shock response" kicks in, which is a physiological reaction that stimulates the release of stress hormones (like cortisol and adrenalin) and other physical adaptations. The result is increased heart rate and blood pressure, and other changes that help us deal with the perceived danger.

At Unbounded, a Toronto retreat focused on cold exposure therapy, breathwork and other wellness experiences, staff help people work through the body's response.

"We teach people how to breathe through it," said co-founder Lisa Kricfalusi, "and to use their body and their own nervous system to down-regulate their stress to bring them in less than 90 seconds from a state of very high stress and anxiety where [their] body's responding — their heart rate, their breathing rate, everything is saying, 'Hey, you're not safe, get out from that state of high stress' — to a state of calm," she said.

Nick McNaught, also a co-founder of Unbounded, says the few minutes he devotes to stressing his body in the cold each morning help him deal with unnerving situations. "[If] I need to have a tough conversation with somebody, or there's just something that I'm putting off … if I've started my day [with a] cold plunge, I'm so much more primed to just go right into that conversation or just handle that thing," he said. 

It may help manage pain and inflammation

Many of us have already dabbled in cold therapy for pain, like when we ice a sprained ankle or prop a bag of frozen peas on our forehead to ease a headache. The jury is still out on icing injuries, however, and only a few small studies have shown that cold exposure can be helpful for recovery after intense bouts of exercise.

Denis Blondin, an assistant professor in the department of medicine at the University of Sherbrooke, has been studying the effects of cold exposure for over a decade. "If your objective is to help your recovery, and to ensure that you're able to recover quickly between training sessions … the cold will help at least reduce some of the inflammation," he said. But he also stresses that scientists are just beginning to explore the impact of cold therapy on exercise performance and recovery. 

Olympic rower Jill Moffatt, who represented Canada at the 2024 Summer Games in Paris, says cold water immersion has become an integral part of her training. "[As athletes], we're looking to do everything we can just to help ourselves recover as quickly as possible," she said. "Myself and my doubles partner were trying to [do a] cold bath almost every day." 

Moffatt's routine to relieve muscle soreness involves cooling down in water that's typically about 10 degrees Celsius for 10 to 15 minutes rather than plunging into icy water for a shorter time. "I definitely feel like it's a little bit better the next day. When you warm up, your legs don't feel so heavy," she said.

There have also been some promising studies showing that cold exposure may help with certain chronic illnesses, said Blondin, particularly where systemic inflammation is involved. "There are some people who are starting to look at [this], especially using cold exposure for certain neurological diseases, [for example] improving symptoms from MS."

It may aid in glucose regulation

Early research has shown that cold therapy can have a positive impact on glucose regulation, said Blondin. "There have been some studies that have been done in individuals with Type 2 diabetes that show that if they expose themselves to the cold every day for 10 consecutive days, on the following day of their last exposure, you'll see these significant improvements in insulin sensitivity and glucose regulation," he said. 

"The thing that is very consistent in this [and] probably the most robust thing that we see is that it definitely improves insulin sensitivity," he added. 

It may give you a mood boost

While winter's darkness and colder temperatures can trigger seasonal depression for some, cold plunge enthusiasts say an icy dip can do wonders for your mental health. 

"There's a reason why, when you see people get out of a cold tub or out of the lake, there's a big smile on their faces," said McNaught. "You feel alive. There's kind of this huge, like, celebration. And that's because you're hopped up on a whole bunch of amazing natural chemicals."

For Gu, the mental benefits of embracing cold exposure even eclipse the physical. "It's been free therapy, essentially. It's connected me to nature in a way that nothing else ever has been able to. All my adventures, all the things that I do outside now gravitate towards being in cold water, and it's just given me such more passion towards being outdoors."

It's a great icebreaker

While the thought of meeting new people or connecting with co-workers while wearing a bathing suit may seem off-putting, enthusiasts say these fears will quickly melt away once it comes time to take the plunge.

McNaught admits that our collective Canadian conservatism and reluctance to being half-naked, especially in front of strangers, has been one of the biggest rubs when it came to expanding his brand. "In Europe, there is a huge bathing culture. You know, people go to the spas naked and it's not even awkward or weird or uncomfortable," he said, adding that Unbounded prioritizes creating a supportive and safe environment, especially for new clients.

"Typically, it's usually like 30 seconds into the cold water, they no longer care what they look like, which is wonderful," McNaught said.

How to test the waters

Gu says starting with a cold shower is a great way to introduce yourself to the practice and see how your body reacts. When it comes to temperature, he also recommends easing in.

"It needs to feel uncomfortable [enough] that you want to get out, but it can't be so uncomfortable that it's teetering on the on the fence of dangerous," he said. "For a lot of people, that's just simply a cold shower. And for some people, it might be even a lukewarm shower and go from there. The key portion is that it's gradual." 

Learning how to move through what is called the "gasp reflex" is helpful, said Kricfalusi. "When you first step in, you have to step in on an exhale, because there's a gasp reflex that's non-negotiable, and happens to everyone, no matter how experienced you are. And that could send someone into a panic." After about 90 seconds of consciously slowing your breathing, she said, you'll reach a "bliss point" as you move from stress to calm. She suggests starting with a two-minute session in 10-degree Celsius water.

McNaught said he sees people getting hooked every day. "There's almost like a hero's journey with this where someone will come [to us] because they … want that Instagram photo of them sitting in an ice hole," he said. "They're a little bit trepidatious but they're down for giving it a shot. And then when they do, it sort of unlocks this whole side of things where they're surprised at how good they feel, or how well they slept, or how good the rest of their day was."