Bond University’s Dr Kevin Kemp-Smith on what he has learned about cold-water immersion

Feeling the cold as winter rolls in? That’s nothing compared to what you’ll experience taking ice baths. But people still swear by them, and there’s mounting research to show they’re right.

As winter rolls in and the ocean gets colder, many surfers and swimmers are trading beach days for beanies – or at least squeezing into wetsuits.

At the same time, there’s a growing number of people doing something that, on the surface, seems completely irrational: deliberately dunking themselves in freezing water.

And they’re not just doing it once – they’re coming back for more.

From celebrities and athletes to everyday people on social media, cold-water immersion (CWI) has exploded in popularity.

As an academic and someone who still has to psych himself up before climbing into 12°C water, I’ve been fascinated by this trend, so I decided to dig deeper.

Together with my colleague Dr Mathew Ono, I led a team at Bond University to investigate what’s really going on beneath the icy surface.

We reviewed the results of 13 international studies, making it, to our knowledge, the first research focused solely on the psychological and physical benefits of CWI in healthy adults.

While our study is new, cold therapy has been around for thousands of years.

Ancient Egyptians used cooling poultices for inflammation, and Hippocrates recommended cold baths for fever.

In the 1920s, Aussies formed winter swimming clubs like the Bondi Icebergs to embrace, not escape, the chill.

It’s about resilience, wellbeing, and – in some cases – identity.

Dr Kevin Kemp-Smith, an Assistant Professor in the School of Physiotherapy at Bond University, pictured using an ice bath.

The athletes get it. CWI has long been a staple of post-training recovery.

Science tells us that cold water reduces muscle soreness, lowers perceived exertion, and triggers a powerful neurochemical cascade.

Adrenaline and noradrenaline surge – those fight-or-flight chemicals that scream “don’t do this” – followed by dopamine, which boosts alertness, focus, and an elevated sense of wellbeing.

Eventually serotonin joins in, helping to relax and stabilise mood.

It’s not just recovery. It’s a rush. And like the runner’s high, it can become addictive in the best possible way.

Celebrities like Lady Gaga, Mark Wahlberg, and Harry Styles have jumped on the ice bath bandwagon, praising CWI for both mental clarity and physical recovery.

But what’s in it for everyday people?

That’s where our research focused. We found four key themes across the studies: physical and psychological benefits, a sense of connectedness, personal growth, and a deepened relationship with nature.

Participants reported improvements in mood, reductions in stress, and a greater awareness of their bodies.

Many talked about how cold water helped them feel more present and more grounded.

Interestingly, cold water immersion is often a shared experience.

Group swims, early-morning plunges with friends, or bonding with strangers in icy water created a strong sense of community.

This social connection, paired with the natural setting – the ocean, lakes, rivers – made the experience even more powerful.

An undated photo of members of the Bondi Icebergs swimming with blocks of ice. Picture: Supplied

The discomfort, it turns out, isn’t a deterrent. It’s part of the appeal.

Facing something that’s physically challenging builds resilience. You override your brain’s panic, you stay calm in the chaos, and you come out the other side stronger.

That’s personal growth. And it’s a skill that carries over into the rest of life.

Of course, cold water immersion isn’t for everyone and there are risks.

The initial shock can cause hyperventilation, elevated heart rate and loss of breath control.

For people with underlying health conditions, the risks can be serious. It’s not something to try on a whim or as part of an online challenge.

That’s why I highly recommend speaking with a medical doctor first.

Conditions like Raynaud’s Syndrome, cardiovascular issues, older age, asthma, being physically exhausted or pregnancy all require extra caution.

For beginners, I suggest starting slow. Two to three sessions a week, one to five minutes at a time.

You don’t need to aim for 4°C. Studies show similar benefits from longer sessions in slightly warmer water – around 15°C. It’s about what’s safe and tolerable for you.

Aside from the mental benefits, there’s evidence that CWI can activate brown and to a lesser extent beige adipose (fat) tissue, which burn calories at a high rate to generate heat. Eliciting the ‘Shivering response’ due to CWI causes involuntary muscle contractions and, similar to the activation of brown fat cells shivering requires energy to generate heat, about 3-4 times above resting levels.

That has exciting implications for metabolism, weight management and even diabetes prevention.

Other research areas findings include reduction in systemic inflammation, improved immune function, and potential benefits for people with arthritis.

My wife and I are now regular ice bath users. We’ve opted for an inflatable tub and a commercial ice machine which isn’t glamorous, but it works.

The cold still gets me every time. I hesitate. But then I take a breath, get in, and find that moment of stillness in the shock.

Across the world, people are trading comfort for clarity, and warmth for resilience.

This winter, lean into the chill – because sometimes cold is the cure.

Dr Kevin Kemp-Smith is an Assistant Professor in the School of Physiotherapy at Bond University.

Originally published as Bond University’s Dr Kevin Kemp-Smith on what he has learned about cold-water immersion